Ultra-processed foods, protein leverage and energy intake in the USA

Association between ultra-processed food consumption, sociodemographic characteristics, malnutrition and obesity among urban school-aged children in Lilongwe, Malawi: a cross-sectional study

INTRODUCTION

The escalating consumption of ultra-processed foods (UPFs) among school-aged children in developing countries poses a significant threat to public health, contributing to the dual burden of malnutrition. In Malawi, where undernutrition coexists with a burgeoning obesity epidemic, understanding the determinants of UPF consumption and its impact on children's nutritional status is imperative. This study, conducted in Lilongwe, Malawi, aimed to investigate the association between UPF consumption, sociodemographic factors and the nutritional status of school-aged children.

MATERIALS AND METHODS

511 children aged 7-14 were recruited from 2 densely populated townships using systematic random sampling. Data on sociodemographic factors, UPF consumption and nutritional status were collected through face-to-face interviews and anthropometric measurements. UPF consumption was assessed using a validated Food Frequency Questionnaire while multinomial logistic regression was employed to analyse associations.

RESULTS

Results revealed alarmingly high UPF consumption among children, particularly those high in sugar. Multinomial logistic regression identified significant predictors of malnutrition outcomes. Notably, children consuming UPFs more than three times a week were more likely to be malnourished. Overweight status was positively associated with sausage intake (β=0.226, adjusted OR 1.254, 95% CI 1.004 to 1.566, p=0.046) and age (β=0.020, adjusted OR=0.257, 95% CI 0.156 to 0.28, p=0.003). Conversely, underweight status was linked with residential location (β=4.507, adjusted OR 0.01, 95% CI 0.000 to 0.281, p=0.006) and fizzy drinks (β=1.071, adjusted OR 2.919, 95% CI 1.413 to 6.028, p=0.004).

CONCLUSION

The high prevalence of UPF consumption among school-aged children is significantly associated with malnutrition. Moreover, sociodemographic factors influence UPF consumption, highlighting the need for targeted interventions to reduce malnutrition. These findings may inform public health policies to mitigate malnutrition among children in Malawi's urban communities.

Infants' Dietary Pattern Characterized by Ultraprocessed Foods Is Associated With Rapid Weight Gain and Overweight/Obesity Risk: National Health and Nutrition Examination Survey 2009-2018

BACKGROUND

Global trends toward childhood obesity have been associated with several factors, including suboptimal infant feeding practices, the increasing availability of ultraprocessed foods in the world's food supply, and the corresponding changes in children's dietary patterns.

OBJECTIVE

To describe infants' dietary patterns and assess their associations with weight status outcomes in a nationally representative sample of US infants.

DESIGN

Cross-sectional analyses were performed on data collected from infants participating in the 2009-2018 National Health and Nutrition Examination Survey.

PARTICIPANTS/SETTING

Participants included 744 infants aged 6 to 12 months who had data from at least 1 day of valid 24-hour dietary recall data.

MAIN OUTCOME MEASURES

Rapid weight gain and overweight/obesity risk.

STATISTICAL ANALYSES PERFORMED

Principal component analysis was used to identify dietary patterns considering the energy intake of 39 Nova food subgroups (expressed in calories per day), including breast milk. Associations were evaluated using logistic regression adjusted for potential confounders.

RESULTS

A total of 42% infants experienced rapid weight gain, and 33% were at risk of overweight/obesity. Most infants (65.5%) were started on solid foods early. Three main dietary patterns were derived. The first pattern, labeled Natural or Minimally Processed Foods, had positive loadings for a variety of natural or minimally processed foods, some processed culinary ingredients, and a few processed and ultraprocessed foods. The second pattern, labeled Infant Formula, had high negative loading for breast milk, and high positive loading for infant formula and breakfast cereal. The third pattern, labeled Ultraprocessed Foods, had negative loadings for natural or minimally processed foods and processed culinary ingredients, positive loadings for other processed foods and for a variety of ultraprocessed foods, and negative loading for infant formula. Infants who adhere to the Ultraprocessed Foods dietary pattern were more likely to present rapid weight gain (adjusted odds ratio 1.3, 95% CI 1.1 to 1.5) and overweight/obesity risk (adjusted odds ratio 1.2, 95% CI 1.0 to 1.4).

CONCLUSIONS

Higher adherence to a dietary pattern characterized by ultraprocessed foods was associated with a greater likelihood of both rapid weight gain and overweight/obesity risk early in life. Promoting breastfeeding and increasing consumption of unprocessed/minimally processed foods during early infancy while restricting ultraprocessed foods are key components to reducing the growing burden of childhood obesity.

Ultra-Processed Food Consumption, Poorer Nutritional Quality, and Lower Muscle Mass in Immediate and Late Postkidney Transplant Periods

OBJECTIVE

To assess the consumption of ultra-processed foods (UPFs) in the immediate (2 months after transplantation) and late post-transplant (14 months after transplantation) periods among kidney transplant patients and to examine its correlation with nutritional quality and body composition.

DESIGN AND METHODS

A cross-sectional analysis of 96 kidney transplant recipients divided into 2 groups: immediate post-transplant (n = 71) and late post-transplant (n = 25). Sociodemographic, anthropometric, and laboratory data were collected and grouped in a database. Food intake was evaluated by a validated food frequency questionnaire and foods were divided according to the NOVA classification system. The consumption of UPFs was calculated and statistical analyses were performed to evaluate its correlation with nutritional components and body composition.

RESULTS

The consumption of UPFs was 649.4 [420.0-1061.72] kcal/day, accounting for 33.3 ± 11.9% of the total daily energy intake. The immediate post-transplant group showed higher total daily energy and UPFs intake compared to the late post-transplant group (P = .002 and P = .046, respectively), although the energy contribution of UPFs was similar between both groups. UPFs intake was positively correlated with higher percentages of total fat, trans fat, saturated, monounsaturated fat, polyunsaturated fat, starch, and sodium (P < .05 for all analyses). An inverse correlation was observed between UPFs consumption and the percentage of protein and carbohydrates in the food intake (P = .025 and P = .008, respectively). In the immediate post-transplant group, a higher intake of UPFs was correlated with lower muscle mass (r = -0.250, P = .037).

CONCLUSIONS

The findings of this study reveal a pattern of increased consumption of UPFs among kidney transplant patients in comparison to the national average. This higher intake of UPFs was correlated with lower nutritional quality during both periods. Moreover, a significant correlation was observed between UPFs consumption and adverse body composition parameters, specifically in the immediate post-transplant period.

Ultra-Processed Foods and Mental Health: Where Do Eating Disorders Fit into the Puzzle?

Ultra-processed foods (UPFs) like pastries, packaged snacks, fast foods, and sweetened beverages have become dominant in the modern food supply and are strongly associated with numerous public health concerns. While the physical health consequences of UPF intake have been well documented (e.g., increased risks of cardiometabolic conditions), less empirical discussion has emphasized the mental health consequences of chronic UPF consumption. Notably, the unique characteristics of UPFs (e.g., artificially high levels of reinforcing ingredients) influence biological processes (e.g., dopamine signaling) in a manner that may contribute to poorer psychological functioning for some individuals. Importantly, gold-standard behavioral lifestyle interventions and treatments specifically for disordered eating do not acknowledge the direct role that UPFs may play in sensitizing reward-related neural functioning, disrupting metabolic responses, and motivating subsequent UPF cravings and intake. The lack of consideration for the influences of UPFs on mental health is particularly problematic given the growing scientific support for the addictive properties of these foods and the utility of ultra-processed food addiction (UPFA) as a novel clinical phenotype endorsed by 14-20% of individuals across international samples. The overarching aim of the present review is to summarize the science of how UPFs may affect mental health, emphasizing contributing biological mechanisms. Specifically, the authors will (1) describe how corporate-sponsored research and financial agendas have contributed to contention and debate about the role of UPFs in health; (2) define UPFs and their nutritional characteristics; (3) review observed associations between UPF intake and mental health conditions, especially with depression; (4) outline the evidence for UPFA; and (5) describe nuanced treatment considerations for comorbid UPFA and eating disorders.

Association between ultra-processed food and snacking behavior in Brazil

PURPOSE

Ultra-processed food may play a role in facilitating snacking behavior because of their convenience and low satiety potential. This study aimed to describe the association between consumption of ultra-processed foods and frequency of snacking.

METHODS

We analyzed data from 46,164 participants (≥ 10 years old) in the 2017-2018 Brazilian Household Budget Survey. Dietary data were collected by 24-h dietary recalls over one or two days for each participant. We estimated energy intake, ultra-processed food consumption, and level of snacking. We measured the association between ultra-processed food consumption and level of snacking using multinomial logistic regression, stratified by age group (adolescents, 10-19 years old; adults, 20-64 years old; elders, 65 or older).

RESULTS

We found a statistically significant tendency of increased daily energy intake and consumption of snacks and that ultra-processed food consumption was positively associated with the level of snacking for all age groups. For adolescents, adults, and elders in the highest quintile of ultra-processed food consumption as a share of their entire diet, the relative risk ratio (95% CI) of having more than two snacks per day compared to no snacks was 14.21 (9.09-22.21), 4.44 (3.54-5.57), and 4.21 (2.67-6.64), respectively, when compared to the lowest quintile.

CONCLUSION

Higher consumption of ultra-processed food was associated with snacking behavior, and the strength of this association was stronger among adolescents. Efforts to mitigate ultra-processed food attributes that facilitate snacking should be incorporated into strategies to promote healthier food choices, especially among adolescents.

Overnutrition, Hyperinsulinemia and Ectopic Fat: It Is Time for A Paradigm Shift in the Management of Type 2 Diabetes

The worldwide incidence of prediabetes/type 2 has continued to rise the last 40 years. In the same period, the mean daily energy intake has increased, and the quality of food has significantly changed. The chronic exposure of pancreatic β-cells to calorie excess (excessive energy intake) and food additives may increase pancreatic insulin secretion, decrease insulin pulses and/or reduce hepatic insulin clearance, thereby causing chronic hyperinsulinemia and peripheral insulin resistance. Chronic calorie excess and hyperinsulinemia may promote lipogenesis, inhibit lipolysis and increase lipid storage in adipocytes. In addition, calorie excess and hyperinsulinemia can induce insulin resistance and contribute to progressive and excessive ectopic fat accumulation in the liver and pancreas by the conversion of excess calories into fat. The personal fat threshold hypothesis proposes that in susceptible individuals, excessive ectopic fat accumulation may eventually lead to hepatic insulin receptor resistance, the loss of pancreatic insulin secretion, hyperglycemia and the development of frank type 2 diabetes. Thus, type 2 diabetes seems (partly) to be caused by hyperinsulinemia-induced excess ectopic fat accumulation in the liver and pancreas. Increasing evidence further shows that interventions (hypocaloric diet and/or bariatric surgery), which remove ectopic fat in the liver and pancreas by introducing a negative energy balance, can normalize insulin secretion and glucose tolerance and induce the sustained biochemical remission of type 2 diabetes. This pathophysiological insight may have major implications and may cause a paradigm shift in the management of type 2 diabetes: avoiding/reducing ectopic fat accumulation in the liver and pancreas may both be essential to prevent and cure type 2 diabetes.

Nutrients or processing? An analysis of food and drink items from the UK National Diet and Nutrition Survey based on nutrient content, the NOVA classification and front of package traffic light labelling

UK front of package labelling (FOPL) informs consumers on the nutrient content of food. However, FOPL does not consider food processing, and with the UK government being urged to act on ultra-processed food (UPF), whether UPF should be added to FOPL is unclear. This study compared food and drink in the UK National Diet and Nutrition Survey (NDNS) Intake24 database based on FOPL, nutrient content and NOVA classification, to understand whether UPF are covered by dietary recommendations for foods high in fat, salt and sugar. NDNS items were coded into minimally processed food (MPF), processed culinary ingredients, processed food and UPF according to the NOVA classification and FOPL traffic lights. UPF contained greater energy, fat, saturated fat (SF), total sugar (TS) and salt than MPF. UPF had a greater odds of containing red FOPL and an unhealthier overall FOPL score (OR:4·59 (95 % CI: 3·79, 5·57); OR:7·0 (95 % CI: 6·1, 8·2), respectively) and lower odds of containing green FOPL (OR:0·05 (95 % CI: 0·03, 0·10)), compared with MPFs. For items with no red FOPL, UPF still contained greater energy, fat, SF, TS and salt than MPF. However, several UPF have healthier FOPL scores. UPF had an unhealthier nutritional profile and FOPL score than MPF. For items with no red FOPL, UPF still had an unhealthier profile than MPF, with a higher energy density. Importantly, not all UPF were unhealthy according to FOPL. These results indicate partial overlap between FOPL, nutrient content and NOVA classification of UK food and drink products, with implications for UK food and drink labelling.

Ultra-processed foods consumption among a USA representative sample of middle-older adults: a cross-sectional analysis

The study evaluated the association between ultra-processed foods (UPF) and nutrient intake and identified the socio-demographic characteristics associated with UPF consumption among a nationally representative sample of middle-older adults. Dietary assessment was collected in 2013 using a validated FFQ. The Nova system was used to classify food and drinks into UPF. The percentage of dietary energy from UPF was calculated and used throughout the analyses, and average nutrient intake across quintiles of UPF was evaluated. The determinants associated with the dietary caloric contribution of UPF intake were investigated using linear regression models. A cross-sectional analysis of a nationally representative study of Americans over the age of 50, the Health and Retirement Study, was conducted. The analysis included 6220 participants. The mean age was 65 (se 0·28) years, with 55 % being female. UPF intake accounted for 51 % (se 0·25) of total intake. An increase in the percentage of (%UPF) consumption was correlated with an increase in calories, carbohydrates, saturated fat and sugar, and a decrease in fibre, vitamins and minerals. %UPF intake was inversely associated with being Hispanic, higher income, physical activity, vegetarian diet and Mediterranean diet but positively associated with very low food insecurity. UPF represented half of the calories consumed. A higher %UPF intake was associated with a lower nutrient profile, suggesting decreasing %UPF intake as a strategy to improve the nutritional quality of middle-older adults. A few socio-demographic factors were associated with %UPF, which would help in planning strategies to reduce UPF consumption.

Integrated Microbiome and Serum Metabolome Analysis Reveals Molecular Regulatory Mechanisms of the Average Daily Weight Gain of Yorkshire Pigs

The average daily weight gain (ADG) is considered a crucial indicator for assessing growth rates in the swine industry. Therefore, investigating the gastrointestinal microbiota and serum metabolites influencing the ADG in pigs is pivotal for swine breed selection. This study involved the inclusion of 350 purebred Yorkshire pigs (age: 90 ± 2 days; body weight: 41.20 ± 4.60 kg). Concurrently, serum and fecal samples were collected during initial measurements of blood and serum indices. The pigs were categorized based on their ADG, with 27 male pigs divided into high-ADG (HADG) and low-ADG (LADG) groups based on their phenotype values. There were 12 pigs in LADG and 15 pigs in HADG. Feces and serum samples were collected on the 90th day. Microbiome and non-targeted metabolomics analyses were conducted using 16S rRNA sequencing and liquid chromatography-mass spectrometry (LC-MS). Pearson correlation, with Benjamini-Hochberg (BH) adjustment, was employed to assess the associations between these variables. The abundance of Lactobacillus and Prevotella in LADG was significantly higher than in HADG, while Erysipelothrix, Streptomyces, Dubosiella, Parolsenella, and Adlercreutzia in LADG were significantly lower than in HADG. The concentration of glutamine, etiocholanolone glucuronide, and retinoyl beta-glucuronide in LADG was significantly higher than in HADG, while arachidonic acid, allocholic acid, oleic acid, phenylalanine, and methyltestosterone in LADG were significantly lower than in HADG. The Lactobacillus-Streptomyces networks (Lactobacillus, Streptomyces, methyltestosterone, phenylalanine, oleic acid, arachidonic acid, glutamine, 3-ketosphingosine, L-octanoylcarnitine, camylofin, 4-guanidinobutyrate 3-methylcyclopentadecanone) were identified as the most influential at regulating swine weight gain. These findings suggest that the gastrointestinal tract regulates the daily weight gain of pigs through the network of Lactobacillus and Streptomyces. However, this study was limited to fecal and serum samples from growing and fattening boars. A comprehensive consideration of factors affecting the daily weight gain in pig production, including gender, parity, season, and breed, is warranted.

Effect of milk fat globules on growth and metabolism in rats fed an unbalanced diet

We assessed the effects of supplementing milk fat globules (MFG) on the growth and development of the skeleton in rats fed a Western unbalanced diet (UBD). The UBD is high in sugar and fat, low in protein, fiber, and micronutrients, and negatively impacts health. The MFG-a complex lipid-protein assembly secreted into milk-has a unique structure and composition, which differs significantly from isolated and processed dietary ingredients. Rats consuming the UBD exhibited growth retardation and disrupted bone structural and mechanical parameters; these were improved by supplementation with small MFG. The addition of small MFG increased the efficiency of protein utilization for growth, and improved trabecular and cortical bone parameters. Furthermore, consumption of UBD led to a decreased concentration of saturated fatty acids and increased levels of polyunsaturated fatty acids (PUFA), particularly omega-6 PUFA, in the serum, liver, and adipose tissue. The addition of small MFG restored PUFA concentration and the ratio of omega-6 to omega-3 PUFA in bone marrow and adipose tissue. Finally, large but not small MFG supplementation affected the cecal microbiome in rats. Overall, our results suggest that natural structure MFG supplementation can improve metabolism and bone development in rats fed an UBD, with the effects depending on MFG size. Moreover, the benefits of small MFG to bone development and metabolism were not mediated by the microbiome, as the detrimental effects of an UBD on the microbiome were not mitigated by MFG supplementation.

Associations between protein to non-protein ratio and intakes of other dietary components in a cohort aged 65-75 years: the Nutrition for Healthy Living Study

OBJECTIVE

Diets with a low proportion of energy from protein have shown to cause overconsumption of non-protein energy, known as Protein Leverage. Older adults are susceptible to nutritional inadequacy. The aim was to investigate associations between protein to non-protein ratio (P:NP) and intakes of dietary components and assess the nutritional adequacy of individuals aged 65-75 years from the Nutrition for Healthy Living (NHL) Study.

DESIGN

Cross-sectional. Nutritional intakes from seven-day weighed food records were compared with the Nutrient Reference Values for Australia and New Zealand, Australian Guide to Healthy Eating, Australian Dietary Guidelines and World Health Organisation Free Sugar Guidelines. Associations between P:NP and intakes of dietary components were assessed through linear regression analyses.

SETTING

NHL Study.

PARTICIPANTS

113 participants.

RESULTS

Eighty-eight (59 female and 29 male) with plausible dietary data had a median (interquartile range) age of 69 years (67-71), high education level (86 %) and sources of income apart from the age pension (81 %). Substantial proportions had intakes below recommendations for dairy and alternatives (89 %), wholegrain (89 %) and simultaneously exceeded recommendations for discretionary foods (100 %) and saturated fat (92 %). In adjusted analyses, P:NP (per 1 % increment) was associated with lower intakes of energy, saturated fat, free sugar and discretionary foods and higher intakes of vitamin B12, Zn, meat and alternatives, red meat, poultry and wholegrain % (all P < 0·05).

CONCLUSIONS

Higher P:NP was associated with lower intakes of energy, saturated fat, free sugar and discretionary. Our study revealed substantial nutritional inadequacy in this group of higher socio-economic individuals aged 65-75 years.

Ultra-processed foods in a rural Ecuadorian community: associations with child anthropometry and bone maturation

Frequent ultra-processed food (UPF) consumption is consistently associated with poor health outcomes. Little is known about UPF intake during early childhood and its effects on growth. We assessed UPF in relation to child anthropometry, bone maturation, and their nutrition profiles in a rural Ecuadorian community. Covariate-adjusted regression models estimated relationships between UPF intake from a 24-hour Food Frequency Questionnaire and three outcomes: linear growth, weight status and bone maturation. Nutrient Profiling Models (NPM) evaluated a convenience sample of UPF (n 28) consumed by children in the community. In this cohort (n 125; mean age = 33·92 (sd 1·75) months), 92·8 % consumed some form of UPF the previous day. On average, children consuming UPF four to twelve times per day (highest tertile) had lower height-for-age z-scores than those with none or a single instance of UPF intake (lowest tertile) (β = -0·43 [se 0·18]; P = 0·02). Adjusted stunting odds were significantly higher in the highest tertile relative to the lowest tertile (OR: 3·07, 95 % CI 1·11, 9·09). Children in the highest tertile had significantly higher bone age z-scores (BAZ) on average compared with the lowest tertile (β = 0·58 [se 0·25]; P = 0·03). Intake of savoury UPF was negatively associated with weight-for-height z-scores (β = -0·30 [se 0·14]; P = 0·04) but positively associated with BAZ (β = 0·77 [se 0·23]; P < 0·001). NPM indicated the availability of unhealthy UPF to children, with excessive amounts of saturated fats, free sugars and sodium. Findings suggest that frequent UPF intake during early childhood may be linked to stunted growth (after controlling for bone age and additional covariates), despite paradoxical associations with bone maturation.

Evidence for the protein leverage hypothesis in preschool children prone to obesity

BACKGROUND & AIMS

The protein leverage hypothesis (PLH) proposed that strict regulation of protein intake drives energy overconsumption and obesity when diets are diluted by fat and/or carbohydrates. Evidence about the PLH has been found in adults, while studies in children are limited. Thus, we aimed to test the PLH by assessing the role of dietary protein on macronutrients, energy intake, and obesity risk using data from preschool children followed for 1.3 years.

METHODS

553 preschool children aged 2-6 years from the 'Healthy Start' project were included.

EXPOSURES

The proportion of energy intake from protein, fat, and carbohydrates collected from a 4-day dietary record.

OUTCOMES

Energy intake, BMI z-score, fat mass (FM) %, waist- (WHtR) and hip-height ratio (HHtR). Power function analysis was used to test the leverage of protein on energy intake. Mixture models were used to explore interactive associations of macronutrient composition on all these outcomes, with results visualized as response surfaces on the nutritional geometry.

RESULTS

Evidence for the PLH was confirmed in preschool children. The distribution of protein intake (% of MJ, IQR: 3.2) varied substantially less than for carbohydrate (IQR: 5.7) or fat (IQR: 6.3) intakes, suggesting protein intake is most tightly regulated. Absolute energy intake varied inversely with dietary percentage energy from protein (L = -0.14, 95% CI: -0.25, -0.04). Compared to children with high fat or carbohydrate intakes, children with high dietary protein intake (>20% of MJ) had a greater decrease in WHtR and HHtR over the 1.3-year follow-up, offering evidence for the PLH in prospective analysis. But no association was observed between macronutrient distribution and changes in BMI z-score or FM%.

CONCLUSIONS

In this study in preschool children, protein intake was the most tightly regulated macronutrient, and energy intake was an inverse function of dietary protein concentration, indicating the evidence for protein leverage. Increases in WHtR and HHtR were principally associated with the dietary protein dilution, supporting the PLH. These findings highlight the importance of protein in children's diets, which seems to have significant implications for childhood obesity risk and overall health.

Diet composition and energy intake in humans

Absolute energy from fats and carbohydrates and the proportion of carbohydrates in the food supply have increased over 50 years. Dietary energy density (ED) is primarily decreased by the water and increased by the fat content of foods. Protein, carbohydrates and fat exert different effects on satiety or energy intake (EI) in the order protein > carbohydrates > fat. When the ED of different foods is equalized the differences between fat and carbohydrates are modest. Covertly increasing dietary ED with fat, carbohydrate or mixed macronutrients elevates EI, producing weight gain and vice versa. In more naturalistic situations where learning cues are intact, there appears to be greater compensation for the different ED of foods. There is considerable individual variability in response. Macronutrient-specific negative feedback models of EI regulation have limited capacity to explain how availability of cheap, highly palatable, readily assimilated, energy-dense foods lead to obesity in modern environments. Neuropsychological constructs including food reward (liking, wanting and learning), reactive and reflective decision making, in the context of asymmetric energy balance regulation, give more comprehensive explanations of how environmental superabundance of foods containing mixtures of readily assimilated fats and carbohydrates and caloric beverages elevate EI through combined hedonic, affective, cognitive and physiological mechanisms. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Protein appetite as an integrator in the obesity system: the protein leverage hypothesis

Despite the large volume and extensive range of obesity research, there is substantial disagreement on the causes and effective preventative strategies. We suggest the field will benefit from greater emphasis on integrative approaches that examine how various potential contributors interact, rather than regarding them as competing explanations. We demonstrate the application of nutritional geometry, a multi-nutrient integrative framework developed in the ecological sciences, to obesity research. Such studies have shown that humans, like many other species, regulate protein intake more strongly than other dietary components, and consequently if dietary protein is diluted there is a compensatory increase in food intake-a process called protein leverage. The protein leverage hypothesis (PLH) proposes that the dilution of protein in modern food supplies by fat and carbohydrate-rich highly processed foods has resulted in increased energy intake through protein leverage. We present evidence for the PLH from a variety of sources (mechanistic, experimental and observational), and show that this mechanism is compatible with many other findings and theories in obesity research. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Food insecurity as a cause of adiposity: evolutionary and mechanistic hypotheses

Food insecurity (FI) is associated with obesity among women in high-income countries. This seemingly paradoxical association can be explained by the insurance hypothesis, which states that humans possess evolved mechanisms that increase fat storage to buffer against energy shortfall when access to food is unpredictable. The evolutionary logic underlying the insurance hypothesis is well established and experiments on animals confirm that exposure to unpredictable food causes weight gain, but the mechanisms involved are less clear. Drawing on data from humans and other vertebrates, we review a suite of behavioural and physiological mechanisms that could increase fat storage under FI. FI causes short-term hyperphagia, but evidence that it is associated with increased total energy intake is lacking. Experiments on animals suggest that unpredictable food causes increases in retained metabolizable energy and reductions in energy expenditure sufficient to fuel weight gain in the absence of increased food intake. Reducing energy expenditure by diverting energy from somatic maintenance into fat stores should improve short-term survival under FI, but the trade-offs potentially include increased disease risk and accelerated ageing. We conclude that exposure to FI plausibly causes increased adiposity, poor health and shorter lifespan. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part II)'.

Low-Carbohydrate Diets in Children and Adolescents With or at Risk for Diabetes

Carbohydrate restriction is increasingly popular as a weight loss strategy and for achieving better glycemic control in people with diabetes, including type 1 and type 2 diabetes. However, evidence to support low-carbohydrate diets in youth (children and adolescents 2-18 years of age) with obesity or diabetes is limited. There are no guidelines for restricting dietary carbohydrate consumption to reduce risk for diabetes or improve diabetes outcomes in youth. Thus, there is a need to provide practical recommendations for pediatricians regarding the use of low-carbohydrate diets in patients who elect to follow these diets, including those with type 1 diabetes and for patients with obesity, prediabetes, and type 2 diabetes. This clinical report will: Provide background on current dietary patterns in youth, describe how moderate-, low-, and very low-carbohydrate diets differ, and review safety concerns associated with the use of these dietary patternsReview the physiologic rationale for carbohydrate reduction in youth with type 1 diabetes and for youth with obesity, prediabetes, and type 2 diabetesReview the evidence for low-carbohydrate diets in the management of youth with type 1 diabetesReview the evidence for low-carbohydrate diets in the management of youth with obesity, prediabetes, and type 2 diabetesProvide practical information for pediatricians counseling families and youth on carbohydrate recommendations for type 1 diabetes and for obesity, prediabetes, and type 2 diabetes.

From dearth to excess: the rise of obesity in an ultra-processed food system

More people now have obesity than suffer from starvation thanks to our modern food system. Agriculture was transformed over the 20th century by a variety of technological advancements that relied heavily on fossil fuels. In the United States, government policies and economic incentives led to surplus production of cheap inputs to processed food industries that produced a wide variety of heavily marketed, convenient, rewarding, timesaving, and relatively inexpensive ultra-processed foods. The energy available in the food supply increased by much more than the population needs, albeit with large inequities in nutrition security. While most of the rise in per capita food availability during the late 20th and early 21st centuries in the United States resulted in increased food waste, a variety of mechanisms have been proposed by which changes in the increasingly ultra-processed food environment resulted in excess energy intake disproportionately in people genetically susceptible to obesity. As populations continue to grow, substantial investments in coordinated nutrition and agricultural research are needed to transform our current food system to one that relies less on fossil fuels, preserves biodiversity, ensures environmental health, and provides equitable access to affordable, safe and nutritious food that reduces the prevalence of chronic diet-related diseases like obesity. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'.

Testing for Protein Leverage in Patients with Gastric Bypass: A Pilot Study

INTRODUCTION

Protein leverage (PL) is the phenomenon whereby a dominant appetite for protein drives overconsumption of energy with a decline in the ratio of protein to fat and carbohydrate in the diet. PL has been independently verified in several randomized control trials, and its predictions are supported by diet surveillance data. Our aim in the present study was to test whether surgical intervention through gastric bypass will ameliorate the PL effect.

METHODS

Ten patients with gastric bypass (2-5 years postsurgical time) were given ad libitum access to study food comprising 10%, 15%, or 25% protein and no access to other foods for 3 days while controlling food palatability and variety. Food intake was measured, and energy and nutrient intakes were calculated. Body weight, blood chemistry, lipid profile, hormones (insulin, leptin, and ghrelin), and creatinine were determined before and after each experimental period.

RESULTS

The gastric bypass patients in our study did not show evidence for protein intake regulation as predicted under PL but ate to constant total energy intake on the 10%, 15%, and 25% protein diets with protein intake varying significantly. Patients lost weight in the three study periods, but significant weight loss was observed only on the 15% protein diet.

CONCLUSION

Our results suggest that gastric bypass might disengage the PL mechanism, thus ameliorating an appetite-specific mechanism that drives energy overconsumption in modern food environments.

Ultraprocessed Foods and Obesity Risk: A Critical Review of Reported Mechanisms

Epidemiologic evidence supports a positive association between ultraprocessed food (UPF) consumption and body mass index. This has led to recommendations to avoid UPFs despite very limited evidence establishing causality. Many mechanisms have been proposed, and this review critically aimed to evaluate selected possibilities for specificity, clarity, and consistency related to food choice (i.e., low cost, shelf-life, food packaging, hyperpalatability, and stimulation of hunger/suppression of fullness); food composition (i.e., macronutrients, food texture, added sugar, fat and salt, energy density, low-calorie sweeteners, and additives); and digestive processes (i.e., oral processing/eating rate, gastric emptying time, gastrointestinal transit time, and microbiome). For some purported mechanisms (e.g., fiber content, texture, gastric emptying, and intestinal transit time), data directly contrasting the effects of UPF and non-UPF intake on the indices of appetite, food intake, and adiposity are available and do not support a unique contribution of UPFs. In other instances, data are not available (e.g., microbiome and food additives) or are insufficient (e.g., packaging, food cost, shelf-life, macronutrient intake, and appetite stimulation) to judge the benefits versus the risks of UPF avoidance. There are yet other evoked mechanisms in which the preponderance of evidence indicates ingredients in UPFs actually moderate body weight (e.g., low-calorie sweetener use for weight management; beverage consumption as it dilutes energy density; and higher fat content because it reduces glycemic responses). Because avoidance of UPFs holds potential adverse effects (e.g., reduced diet quality, increased risk of food poisoning, and food wastage), it is imprudent to make recommendations regarding their role in diets before causality and plausible mechanisms have been verified.

Ultra-processed foods and the development of obesity in adults

Ultra-processed foods (UPF) are ubiquitous in the modern-day food supply and widely consumed. High consumption of these foods has been suggested to contribute to the development of obesity in adults. The purpose of this review is to present and evaluate current literature on the relationship between UPF consumption and adult obesity. Cross-sectional studies (n = 9) among different populations worldwide show a positive association between UPF consumption and obesity. Longitudinal studies (n = 7) further demonstrate a positive association between UPF consumption and development of obesity, suggesting a potential causal influence of UPF consumption on obesity risk. However, only one randomized controlled trial has tested the causality of this association. The study included in this review found greater energy intake and weight gain with consumption of a high UPF diet compared to a high unprocessed food diet. The potential mechanisms by which UPF increase the risk of obesity include increased energy intake due to increased sugar consumption, decreased fiber consumption, and decreased protein density; however, more research is needed. Overall, the evidence identified in the current review consistently support a positive relation between high UPF consumption and obesity. While there is a need for more experimental research to establish causality and elucidate the mechanisms, the sum of the evidence supports a need for research on treatment modalities that include reductions in UPF consumption for the management of adult obesity.

The contribution to policies of an exposome-based approach to childhood obesity

Childhood obesity is an increasingly severe public health problem, with a prospective impact on health. We propose an exposome approach to identify actionable risk factors for this condition. Our assumption is that relationships between external exposures and outcomes such as rapid growth, overweight, or obesity in children can be better understood through a "meet-in-the-middle" model. This is based on a combination of external and internal exposome-based approaches, that is, the study of multiple exposures (in our case, dietary patterns) and molecular pathways (metabolomics and epigenetics). This may strengthen causal reasoning by identifying intermediate markers that are associated with both exposures and outcomes. Our biomarker-based studies in the STOP consortium suggest (in several ways, including mediation analysis) that branched-chain amino acids (BCAAs) could be mediators of the effect of dietary risk factors on childhood overweight/obesity. This is consistent with intervention and animal studies showing that higher intake of BCAAs has a positive impact on body composition, glycemia, and satiety. Concerning food, of particular concern is the trend of increasing intake of ultra-processed food (UPF), including among children. Several mechanisms have been proposed to explain the impact of UPF on obesity and overweight, including nutrient intake (particularly proteins), changes in appetite, or the role of additives. Research from the Avon Longitudinal Study of Parents and Children cohort has shown a relationship between UPF intake and trajectories in childhood adiposity, while UPF was related to lower blood levels of BCAAs. We suggest that an exposome-based approach can help strengthening causal reasoning and support policies. Intake of UPF in children should be restricted to prevent obesity.

Evidence for protein leverage in a general population sample of children and adolescents

BACKGROUND/OBJECTIVES

The strong regulation of protein intake can lead to overconsumption of total energy on diets with a low proportion of energy from protein, a process referred to as protein leverage. The protein leverage hypothesis posits that protein leverage explains variation in energy intake and potentially obesity in ecological settings. Here, we tested for protein leverage and the protein leverage hypothesis in children and adolescents.

SUBJECTS/METHODS

A population sample of children, mean (SD) age 7.6 (0.4) years (n = 422), followed up at age 9.8 (0.4) years (n = 387) and at age 15.8 (0.4) years (n = 229), participating for the Physical Activity and Nutrition in Children (PANIC) study.

EXPOSURES

4-day food records-related proportional energy intake of proteins, fats, and carbohydrates.

OUTCOMES

energy intake, body mass index (BMI) z-score and dual-energy X-ray absorptiometry-related energy expenditure.

RESULTS

Proportional energy intake of proteins was inversely associated with energy intake following power functions at all 3 ages (mean [95%CI] strength of leverage of L = -0.36 [-0.47 to -0.25]; L = -0.26 [-0.37 to -0.15]; L = -0.25 [-0.38 to -0.13]; all P < 0.001). Mixture analysis indicated that variance in energy intake was associated primarily with the proportional intake of energy from proteins, not with either fats or carbohydrates. At all 3 ages, energy intake was not associated with BMI z-score but positively associated with energy expenditure (all P < 0.001).

CONCLUSIONS

This study provides evidence consistent with protein leverage in a population sample of children and adolescents. Increased energy intake on diets with lower protein content was counterbalanced by increased energy expenditure and therefore did not translate into increased adiposity.

Multi-Nutrient Analysis of Dietary Macronutrients with All-Cause, Cardiovascular, and Cancer Mortality: Data from NHANES 1999-2014

Macronutrients are a major component of the human diet. However, few studies have assessed their collective association with mortality. We sought to evaluate the associations of macronutrient intake with all-cause, cardiovascular, and cancer mortality in US adults using a multi-nutrient approach. This prospective cohort analysis used data from the National Health and Nutrition Examination Survey from the years 1999 to 2014. The participants included 33,681 US adults aged 20−85 years (52.5% female). The maximum follow-up time was 16.8 years, with a total of 4398 total deaths, including 772 cardiovascular deaths and 952 cancer deaths. The associations between mortality and dietary macronutrients were explored using three-dimensional generalized additive models, allowing for visual and statistical inference of complex nonlinear associations. Absolute macronutrient intake demonstrated a three-way interactive association with all-cause mortality (p < 0.001), cardiovascular mortality (p = 0.02), and cancer mortality (p = 0.05), adjusted for age, sex, ethnicity, socioeconomic status, dietary quality, and lifestyle. Compositionally, a high caloric diet composed of moderately high protein (20%), moderate fat (30%), and moderate carbohydrate (50%) levels was associated with the highest mortality risk. Across the total energy intake levels, lower mortality risk was observed in two separate regions consisting of higher protein (30%), higher carbohydrate (60%), and lower fat levels (10%) or lower protein (10%), moderate carbohydrate (45%), and higher fat levels (45%). These findings highlight a complex nonlinear and interactive association between macronutrients and all-cause mortality such that several distinct dietary compositions are associated with similarly high or low risk. Future research is needed to explore the drivers of these associations and whether they differ across varying dietary patterns and populations.

NOVA food groups' consumption associated with nutrient intake profile of school children aged 8-12 years

OBJECTIVE

To evaluate the association between the consumption of NOVA food groups (classification based on the nature, extent and purpose of food processing) and the intake of energy, macro and micronutrients among school children.

DESIGN

Cross-sectional study. Food consumption was assessed by two 24-h dietary recalls on non-consecutive days. Energy from each NOVA food groups - ultra-processed foods, unprocessed or minimally processed foods, processed culinary ingredients and processed foods - was estimated. For analysis, the percentage of energy from ultra-processed foods and unprocessed or minimally processed foods were categorised into tertiles and associated with intake of energy, macro and micronutrients using analysis of covariance and linear regression.

SETTING

Public schools in Belo Horizonte, Minas Gerais, Brazil.

PARTICIPANTS

School children aged 8-12 years (n 797; 406 girls; 391 boys).

RESULTS

Mean energy intake was 2050·18 ± 966·83 kcal/d, 25·8 % was from ultra-processed foods, 56·7 % from unprocessed or minimally processed foods, 8·9 % from processed culinary ingredients and 8·6 % from processed foods. A higher energy contribution from ultra-processed foods was negatively associated with the intake of protein, fibre, vitamin A, Fe and Zn (P < 0·001) and positively associated with total energy, lipid and Na intake (P < 0·001). Concurrently, a higher energy contribution from unprocessed or minimally processed foods was positively associated with the consumption of protein, fibre, Fe and Zn (P < 0·001) and negatively associated with total energy (P = 0·002), lipid and Na intake (P < 0·001).

CONCLUSIONS

In conclusion, higher ultra-processed food consumption presented a negative association with the nutrient intake profile of school children.

Macronutrient (im)balance drives energy intake in an obesogenic food environment: An ecological analysis

OBJECTIVE

The protein leverage hypothesis (PLH) postulates that strong regulation of protein intake drives energy overconsumption and obesity when human diets are diluted by fat and carbohydrates. The two predictions of the PLH are that humans (i) regulate intake to maintain protein within a narrow range and that (ii) energy intake is an inverse function of percentage energy from protein because absolute protein intake is maintained within narrow limits.

METHODS

Multidimensional nutritional geometry was used to test the predictions of the PLH using dietary data from the Australian National Nutrition and Physical Activity Survey.

RESULTS

Both predictions of the PLH were confirmed in a population setting: the mean protein intake was 18.4%, and energy intake decreased with increasing energy from protein (L = -0.18, p &lt; 0.0001). It was demonstrated that highly processed discretionary foods are a significant diluent of protein and associated with increased energy but not increased protein intake.

CONCLUSIONS

These results support an integrated ecological and mechanistic explanation for obesity, in which low-protein highly processed foods lead to higher energy intake because of the biological response to macronutrient imbalance driven by a dominant appetite for protein. This study supports a central role for protein in the obesity epidemic, with significant implications for global health.

A Comparison of the Australian Dietary Guidelines to the NOVA Classification System in Classifying Foods to Predict Energy Intakes and Body Mass Index

NOVA classification distinguishes foods by level of processing, with evidence suggesting that a high intake of ultra-processed foods (UPFs, NOVA category 4) leads to obesity. The Australian Dietary Guidelines, in contrast, discourage excess consumption of “discretionary foods” (DFs), defined according to their composition. Here, we (i) compare the classification of Australian foods under the two systems, (ii) evaluate their performance in predicting energy intakes and body mass index (BMI) in free-living Australians, and (iii) relate these outcomes to the protein leverage hypothesis of obesity. Secondary analysis of the Australian National Nutrition and Physical Activity Survey was conducted. Non-protein energy intake increased by 2.1 MJ (p < 0.001) between lowest and highest tertiles of DF intake, which was significantly higher than UPF (0.6 MJ, p < 0.001). This demonstrates that, for Australia, the DF classification better distinguishes foods associated with high energy intakes than does the NOVA system. BMI was positively associated with both DFs (−1. 0, p = 0.0001) and UPFs (−1.1, p = 0.0001) consumption, with no difference in strength of association. For both classifications, macronutrient and energy intakes conformed closely to the predictions of protein leverage. We account for the similarities and differences in performance of the two systems in an analysis of Australian foods.

The degree of food processing is associated with anthropometric measures of obesity in Canadian families with preschool-aged children

Adopting a healthy diet remains central for the prevention of obesity. In adults, higher intake of ultra-processed food is associated with a greater risk of overweight and obesity. However, little is known about the degree of food processing and its association with anthropometric measures in families with preschool-aged children, a critical period for the development of dietary patterns. This cross-sectional study included preschool-aged children (n = 267) between 1.5 and 5 years of age and their parents (n = 365) from 242 families enrolled in the Guelph Family Health Study. Dietary assessment was completed using ASA24-Canada-2016. Foods and beverages were classified based on their degree of food processing using the NOVA Classification (unprocessed or minimally processed foods, processed culinary ingredients, processed foods, and ultra-processed foods). Associations between the energy contribution (% kcal) of each NOVA category and anthropometric measures were examined using linear regression models with generalized estimating equations, adjusted for sociodemographic variables. The energy contribution of ultra-processed foods was the highest relative to the other NOVA categories among parents (44.3%) and children (41.3%). The energy contribution of unprocessed or minimally processed foods was 29.1% for parents and 35.3% for children, processed foods was 24.0% for parents and 21.3% for children, and processed culinary ingredients was 2.6% for parents and 2.1% for children. Ultra-processed foods (% kcal) were positively associated with BMI (β = 0.04, 95% CI: 0.01–0.07, P = 0.02), waist circumference (β = 0.11, 95% CI: 0.03–0.18, P = 0.008) and body weight (β = 0.13, 95% CI: 0.03–0.22, P = 0.01) in parents, but not children. Unprocessed foods (% kcal) were negatively associated with waist circumference in parents (β = −0.09, 95% CI: 0.18–0.01, P = 0.03) and children (β = −0.03, 95% CI: 0.05–0.01, P = 0.01), as well as body weight (β = −0.12, 95% CI: 0.23–0.00, P = 0.04) in parents. The degree of food processing primarily influenced anthropometric outcomes in parents. Nevertheless, diets of children were similar, suggesting that such exposure in families may eventually lead to outcomes observed in parents.

Testing the protein-leverage hypothesis using population surveillance data

It is hypothesized that humans exhibit 'protein leverage' (PL), whereby regulation of absolute protein intake results in the over-consumption of non-protein food on low percentage protein diets. Testing for PL using dietary surveillance data involves seeking evidence for a negative association between total energy intake and percentage energy from protein. However, it is unclear whether such an association might emerge without PL due to the structure of intake data (protein and non-protein intakes have different means and variances and covary). We derive a set of models that describe the association between the expected estimate of PL and the distributions of protein and non-protein intake. Models were validated via simulation. Patterns consistent with PL will not emerge simply because protein intake has a lower mean and/or variance than non-protein. Rather, evidence of PL is observed where protein has a lower index of dispersion (variance/mean) than non-protein intake. Reciprocally, the stronger PL is the lower the index of dispersion for protein intake becomes. Disentangling causality is ultimately beyond the power of observational data alone. However, we show that one can correct for confounders (e.g. age) in generating signals of PL, and describe independent measures that can anchor inferences around the role of PL.

Stone tools improve diet quality in wild monkeys

Tool use is a fundamental feature of human evolution. Stone tools are in the archaeological record from 3.4 Ma, even before Homo,¹ and the use of stone tools probably predated the split between hominins and panins.² Using tools (hereafter, tooling cf Fragaszy and Mangalam³) is hypothesized to have improved hominins' foraging efficiency or access to high-quality foods.^4-7 This hypothesis is supported if feeding with tools positively contributes to diet quality in extant non-human primates or if foraging efficiency is increased by tooling. However, the contribution of tooling to non-human primates' foraging success has never been investigated through a direct analysis of nutritional ecology.^8,9 We used multi-dimensional nutritional geometry to analyze energy and macronutrients (nonstructural carbohydrates, lipids, and protein) in the diets of wild capuchin monkeys (Sapajus libidinous) that routinely crack palm nuts with stone hammers.^10,11 We show that eating nuts obtained through tooling helps monkeys to achieve more consistent dietary intakes. Tooling increased the net energy gain by 50% and decreased the proportion of fiber ingested by 7%. Tooling also increased the daily non-protein energy intake. By contrast, protein intake remained constant across foraging days, suggesting a pattern of macronutrient regulation called protein prioritization, which is also found in contemporary humans.^8,9 In addition, tooling reduced dispersion in the ratio of protein to non-protein energy, suggesting a role in macronutrient balancing. Our findings suggest that tooling prior to tool making could have substantially increased the nutritional security of ancestral hominins, sowing the seeds for cultural development.^5,7 VIDEO ABSTRACT.

Associations of ultra-processed food intake with maternal weight change and cardiometabolic health and infant growth

BACKGROUND

Excessive intake of ultra-processed foods, formulated from substances extracted from foods or derived from food constituents, may be a modifiable behavioral risk factor for adverse maternal and infant health outcomes. Prior work has predominately examined health correlates of maternal ultra-processed food intake in populations with substantially lower ultra-processed food intake compared to the US population. This longitudinal study investigated relations of ultra-processed food intake with maternal weight change and cardiometabolic health and infant growth in a US cohort.

METHODS

Mothers in the Pregnancy Eating Attributes Study were enrolled at ≤12 weeks gestation and completed multiple 24-Hour Dietary Recalls within six visit windows through one-year postpartum (458 mothers enrolled, 321 retained at one-year postpartum). The NOVA (not an acronym) system categorized food and underlying ingredient codes based on processing level. Maternal anthropometrics were measured throughout pregnancy and postpartum, and infant anthropometrics were measured at birth and ages 2 months, 6 months, and 1 year. Maternal cardiometabolic markers were analyzed from blood samples obtained during the second and third trimesters.

RESULTS

Holding covariates and total energy intake constant, a 1-SD greater percent energy intake from ultra-processed foods during pregnancy was associated with 31% higher odds of excessive gestational weight gain (p = .045, 95% CI [1.01, 1.70]), 0.68±0.29 mg/L higher c-reactive protein during pregnancy (p = .021, 95% CI [0.10, 1.26]), 6.7±3.4% greater gestational weight gain retained (p = .049, 95% CI [0.03, 13.30]), and 1.09±0.36 kg greater postpartum weight retention (p = .003, 95% CI [0.38, 1.80]). No other significant associations emerged.

CONCLUSIONS

Ultra-processed food intake during pregnancy may be a modifiable behavioral risk factor for adverse maternal weight outcomes and inflammation. Randomized controlled trials are needed to test whether targeting ultra-processed food intake during pregnancy may support optimal maternal health.

TRIAL REGISTRATION

Clinicaltrials.gov. Registration ID - NCT02217462 . Date of registration - August 13, 2014.

An integrative approach to dietary balance across the life course

Animals require specific blends of nutrients that vary across the life course and with circumstances, e.g., health and activity levels. Underpinning and complicating these requirements is that individual traits may be optimized on different dietary compositions leading to nutrition-mediated trade-offs among outcomes. Additionally, the food environment may constrain which nutrient mixtures are achievable. Natural selection has equipped animals for solving such multi-dimensional, dynamic challenges of nutrition, but little is understood about the details and their theoretical and practical implications. We present an integrative framework, nutritional geometry, which models complex nutritional interactions in the context of multiple nutrients and across levels of biological organization (e.g., cellular, individual, and population) and levels of analysis (e.g., mechanistic, developmental, ecological, and evolutionary). The framework is generalizable across different situations and taxa. We illustrate this using examples spanning insects to primates and settings (laboratory, and the wild), and demonstrate its relevance for human health.

Consumption of ultra-processed foods and IL-6 in two cohorts from high- and middle-income countries

This study evaluated the association between ultra-processed foods (UPF) on serum IL-6 and to investigate the mediation role of adiposity. Participants were 524 adults from the EPITeen Cohort (Porto, Portugal) and 2888 participants from the 1982 Pelotas Birth Cohort (Pelotas, Brazil). Dietary intake was collected using FFQ when participants were 21 years of age in the EPITeen and 23 years in the Pelotas Cohort. Serum IL-6 and body fat mass were evaluated when participants were 27 and 30 years old in the EPITeen and Pelotas, respectively. Generalised linear models were fitted to test main associations. Mediation of body fat mass was estimated using G-computation. After adjustment for socio-economic and behaviour variables, among females from the EPITeen, the concentration of IL-6 (pg/ml) increased with increasing intake of UPF from 1·31 (95 % CI 0·95, 1·82) in the first UPF quartile to 2·20 (95 % CI 1·60, 3·01) and 2·64 (95 % CI 1·89, 3·69) for the third and fourth UPF quartiles, respectively. A similar result was found among males in the Pelotas Cohort, IL-6 increased from 1·40 (95 % CI 1·32, 1·49) in the first UPF quartile to 1·50 (95 % CI 1·41, 1·59) and 1·59 (95 % CI 1·49, 1·70) in the two highest UPF quartiles. The P-value for the linear trend was < 0·01 in both findings. The indirect effect through fat mass was NS. Our findings suggest that the consumption of UPF was associated with an increase in IL-6 concentration; however, this association was not explained by adiposity.

Meal-to-meal and day-to-day macronutrient variation in an ad libitum vending food paradigm

BACKGROUND

Theory posits that macronutrient intake is regulated by protein consumption and adequate intake of protein results in consumption of less carbohydrates and fat. The current study investigates the effect of protein intake on calorie and macronutrient content using an ad libitum vending machine paradigm.

METHODS

Healthy volunteers (n = 287; 177 m; Age = 36 ± 11; BMI = 32 ± 8) were admitted to our clinical research unit. Macronutrient meal content (grams) and energy intake (Kcal) were quantified by specialized food processing software and collected on an hourly basis over a three-day period using a validated ad libitum vending machine paradigm. Body composition was assessed by DXA. Lagged multi-level models accounting for age, sex, race/ethnicity, fat and fat free mass indices were fitted to examine the impact of prior macronutrient content on subsequent meals.

RESULTS

Protein intake was associated with decreased energy intake (Kcal; B = -1.67 kcal, p = 0.0048), lower protein and carbohydrate intake (B = -0.08 g, p = 0.0006; B = -0.21 g, p = 0.0003, respectively) at subsequent meals. Daily Macronutrient intake and subsequent intake were positively associated.

CONCLUSIONS

Dietary protein exhibits a negative regulatory effect on a short-term meal-to-meal rather than day-to-day basis. In the setting of readily available food, protein intake impacts energy intake only over very short time courses.

Ultraprocessed food consumption and dietary nutrient profiles associated with obesity: A multicountry study of children and adolescents

This study assessed associations between ultraprocessed food consumption and dietary nutrient profile linked to obesity in children and adolescents in Argentina, Australia, Brazil, Chile, Colombia, Mexico, the United Kingdom, and the United States using nationally representative data collected between 2004 and 2014. Linear regression models were used to evaluate associations between dietary share of ultraprocessed foods (country and age group-specific quintiles and a 10% share increase) and the energy density of diets and their content of free sugars and fiber. Ultraprocessed foods, defined by the NOVA system, ranged from 18% of total energy intake among preschool children in Colombia to 68% among adolescents in the United Kingdom. In almost all countries and age groups, increases in the dietary share of ultraprocessed foods were associated with increases in energy density and free sugars and decreases in fiber, suggesting that ultraprocessed food consumption is a potential determinant of obesity in children and adolescents. Effective global policy action to address growing ultraprocessed food consumption and childhood obesity is urgently needed.

Relative Validity of a Semi-Quantitative Food Frequency Questionnaire to Estimate Dietary Intake According to the NOVA Classification in Mexican Children and Adolescents

BACKGROUND

Ultra-processed foods (UPFs) are associated with poor diet quality and chronic diseases. UPFs fall into 1 of the following 4 groups classified according to the extent and purpose of processing: group 1 is unprocessed or minimally processed foods (MPFs); group 2 is processed culinary ingredients; group 3 is processed foods; and group 4 is UPFs.

OBJECTIVE

The aim of this study was to evaluate the relative validity of a semi-quantitative food frequency questionnaire (SFFQ) compared with two 24-hour dietary recalls (24DRs) to estimate dietary intake per NOVA food group in Mexican children and adolescents.

DESIGN

This study is a secondary analysis of dietary data from a subsample of children and adolescents who participated in the 2012 Mexican National Health and Nutrition Survey.

PARTICIPANTS/SETTING

The study participants were 217 children (aged 5 through 11 years) and 165 adolescents (aged 12 through 19 years) with complete information for the SFFQ and two 24DRs.

MAIN OUTCOME MEASURES

Daily averages of energy intake and percent of energy intake for each NOVA category were calculated using the SFFQ and two 24DRs.

STATISTICAL ANALYSIS

To assess relative validity, the SFFQ was compared with two 24DRs to estimate dietary intake per NOVA food group. Mean differences, Spearman correlations, intraclass correlations coefficients (ICCs), and Bland-Altman plots for continuous variables and weighted κ for ordinal variables were calculated.

RESULTS

For percentage of energy intake, ICCs in children and adolescents were moderate for MPFs (ICC = 0.47 and ICC = 0.56, respectively) and UPFs (ICC = 0.53 and ICC = 0.57, respectively). Bland-Altman plots indicated reasonably consistent agreement for UPFs and MPFs groups in children and adolescents. Classification by quintiles was acceptable in all groups.

CONCLUSIONS

Data from this study indicated reasonable relative validity of the SFFQ to rank the percentage of energy intake from MPFs and UPFs in Mexican children and adolescents.

The future of human malnutrition: rebalancing agency for better nutritional health

The major threat to human societies posed by undernutrition has been recognised for millennia. Despite substantial economic development and scientific innovation, however, progress in addressing this global challenge has been inadequate. Paradoxically, the last half-century also saw the rapid emergence of obesity, first in high-income countries but now also in low- and middle-income countries. Traditionally, these problems were approached separately, but there is increasing recognition that they have common drivers and need integrated responses. The new nutrition reality comprises a global ‘double burden’ of malnutrition, where the challenges of food insecurity, nutritional deficiencies and undernutrition coexist and interact with obesity, sedentary behaviour, unhealthy diets and environments that foster unhealthy behaviour. Beyond immediate efforts to prevent and treat malnutrition, what must change in order to reduce the future burden? Here, we present a conceptual framework that focuses on the deeper structural drivers of malnutrition embedded in society, and their interaction with biological mechanisms of appetite regulation and physiological homeostasis. Building on a review of malnutrition in past societies, our framework brings to the fore the power dynamics that characterise contemporary human food systems at many levels. We focus on the concept of agency, the ability of individuals or organisations to pursue their goals. In globalized food systems, the agency of individuals is directly confronted by the agency of several other types of actor, including corporations, governments and supranational institutions. The intakes of energy and nutrients by individuals are powerfully shaped by this ‘competition of agency’, and we therefore argue that the greatest opportunities to reduce malnutrition lie in rebalancing agency across the competing actors. The effect of the COVID-19 pandemic on food systems and individuals illustrates our conceptual framework. Efforts to improve agency must both drive and respond to complementary efforts to promote and maintain equitable societies and planetary health.

Interactive influences of food, contexts and neurocognitive systems on addictive eating

Compulsive eating is a common symptom of different conditions, including obesity, binge eating disorder and bulimia. One hypothesis is that contemporary food products promote compulsive eating via addiction-like mechanisms. However, what is the addictive substance in food, and what is the phenotypic overlap between obesity / eating disorders and addictions are questions that remain unresolved. In this review, we applied a multilevel framework of addiction, which encompasses the 'drug' (certain foods), the person's mindset, and the context, to improve understanding of compulsive eating. Specifically, we reviewed evidence on the addictive properties of specific foods, the neurocognitive systems that control dietary choices, and their interaction with physical, emotional and social contexts. We focused on different target groups to illustrate distinct aspects of the proposed framework: the impact of food and contextual factors were examined across a continuum, with most studies conducted on healthy participants and subclinical populations, whereas the review of neurocognitive aspects focused on clinical groups in which the alterations linked to addictive and compulsive eating are particularly visible. The reviewed evidence suggest that macronutrient composition and level of processing are associated with the addictive properties of food; there are overlapping neuroadaptations in reward and decision-making circuits across compulsive eating conditions; and there are physical and social contexts that fuel compulsive eating by exploiting reward mechanisms and their interaction with emotions. We conclude that a biopsychosocial model that integrates food, neurobiology and context can provide a better understanding of compulsive eating manifestations in a transdiagnostic framework.

Nutritional geometry of female chimpanzees (Pan troglodytes)

Primate foraging is influenced by the spatial and temporal distribution of foods, which may facilitate or constrain optimal nutrient intakes. Chimpanzees are frugivorous primates that mainly subsist on ripe fruit that is typically low in available protein (AP) and high in easily digestible carbohydrates. Because chimpanzees prefer ripe fruit and often eat it in large quantities compared with other foods, we hypothesized that protein intake would be tightly regulated while non-protein energy (NPE) would vary with fruit intake. To test this hypothesis, we conducted all-day follows on female chimpanzees, recorded all types of food consumed (i.e., drupes, figs, and non-fruit foods), estimated the nutritional contributions of these foods to daily NPE and AP intake and investigated how the ratio of NPE to AP varied due to changes in the types of foods consumed. Although the proportions of drupes, figs, and non-fruit foods varied in their diets, female chimpanzees maintained a relatively stable intake of AP while intake of NPE varied depending on the daily diet, demonstrating that like other frugivorous primates studied to date, chimpanzees prioritize protein. The mean daily ratio of NPE to AP was 7:1, which is similar to that of other frugivorous primates studied. Our results support the hypothesis that frugivorous animals may generally prioritize AP, while maximizing NPE intake within that constraint, and could shed light on aspects of human dietary evolution.

Contrary to ultra-processed foods, the consumption of unprocessed or minimally processed foods is associated with favorable patterns of protein intake, diet quality and lower cardiometabolic risk in French adults (INCA3)

PURPOSE

While the consumption of ultra-processed foods is steadily increasing, there is a growing interest in more sustainable diets that would include more plant protein. We aimed to study associations between the degree of food processing, patterns of protein intake, diet quality and cardiometabolic risk.

METHODS

Using the NOVA classification, we assessed the proportion of energy from unprocessed/minimally processed foods (MPFp), processed foods (PFp) and ultra-processed foods (UPFp) in the diets of 1774 adults (18-79 years) from the latest cross-sectional French national survey (INCA3, 2014-2015). We studied the associations between MPFp, PFp and UPFp with protein intakes, diet quality (using the PANDiet scoring system, the global (PDI), healthful (hPDI) and unhealthful (uPDI) plant-based diet indices) and risk of cardiometabolic death (using the EpiDiet model).

RESULTS

MPFp was positively associated with animal protein intake and plant protein diversity, whereas PFp was positively associated with plant protein intake and negatively with plant protein diversity. The PANDiet was positively associated with MPFp (β = 0.14, P < 0.0001) but negatively with UPFp (β = - 0.05, P < 0.0001). These associations were modified by adjustment for protein intakes and plant protein diversity. As estimated with comparative risk assessment modeling between extreme tertiles of intake, mortality from cardiometabolic diseases would be decreased with higher MPFp (e.g. by 31% for ischemic heart diseases) and increased with higher UPFp (by 42%) and PFp (by 11%).

CONCLUSIONS

In the French population, in contrast with UPFp, higher MPFp was associated with higher animal protein intake, better plant protein diversity, higher diet quality and markedly lower cardiometabolic risk.

Obesity and Male Reproduction; Placing the Western Diet in Context

There is mounting evidence that obesity has negative repercussions for reproductive physiology in males. Much of this evidence has accumulated from rodent studies employing diets high in fat and sugar ("high fat" or "western" diets). While excessive fats and carbohydrates have long been considered major determinants of diet induced obesity, a growing body of research suggests that the relationships between diet composition and obesity are more complex than originally thought, involving interactions between dietary macronutrients. However, rodent dietary models have yet to evolve to capture this, instead relying heavily on elevated levels of a single macronutrient. While this approach has highlighted important effects of obesity on male reproduction, it does not allow for interpretation of the complex, interacting effects of dietary protein, carbohydrate and fat. Further, the single nutrient approach limits the ability to draw conclusions about which diets best support reproductive function. Nutritional Geometry offers an alternative approach, assessing outcomes of interest over an extended range of dietary macronutrient compositions. This review explores the practical application of Nutritional Geometry to study the effects of dietary macronutrient balance on male reproduction, including experimental considerations specific to studies of diet and reproductive physiology. Finally, this review discusses the promising use of Nutritional Geometry in the development of evidence-based pre-conception nutritional guidance for men.

Energy contribution of NOVA food groups and the nutritional profile of the Brazilian rural workers' diets

We estimated the caloric contribution of minimally processed foods, processed culinary ingredients, processed foods and ultra-processed foods in Brazilian farmers' diets and their association with the nutritional profile of the diet. It is an epidemiological study of cross-sectional, analytical and quantitative design with 740 farmers adults of Southeastern Brazil. Food intake data were obtained by applying three 24-hour recalls and were classified according to the degree and purpose of processing. The largest caloric contribution came from the group of minimally processed foods (64.7%), followed by ultra-processed foods (17.7%), processed culinary ingredients (12.4%), and processed foods (5.2%). Individuals in the fourth quartile of caloric contribution from minimally processed foods showed lower energy consumption (β -0.16, P<0.001) and greater consumption of all 15 micronutrients analyzed. In contrast to what was identified for this food group, the higher caloric contribution from ultra-processed foods was associated with a greater caloric content of the diet (β 0.17, P<0.001) and lower consumption of all 23 analyzed nutrients. Therefore, the caloric contribution from the consumption of ultra-processed foods in the rural area is still lower than the national average. However, measures aimed at delaying isocaloric exchanges for the group of ultra-processed foods must be carried out, maintaining the local food culture, since this group had worse nutritional levels. In addition, incentives to the greater consumption of minimally processed foods should be carried out, due to their nutritional quality.

Ultra-processed foods and binge eating: A retrospective observational study

OBJECTIVES

There is increasing evidence of the impact of ultra-processed foods on multiple metabolic and neurobiological pathways, including those involved in eating behaviors, both in animals and in humans. In this study we aimed to explore ultra-processed foods and their link with disordered eating in a clinical sample.

METHODS

This was a single site, retrospective observational study in a specialist eating disorder service using self-report on the electronic health records. Patients with a Diagnostic and Statistical Manual of Mental Disorders (fifth edition) diagnosis of anorexia nervosa (AN), bulimia nervosa (BN), or binge eating disorder (BED) were randomly selected from the service database in Oxford from 2017 to 2019. The recently introduced NOVA classification was used to determine the degree of industrial food processing in each patient's diet. Frequencies of ultra-processed foods were analyzed for each diagnosis at each mealtime and during episodes of binging.

RESULTS

A total of 70 female and 3 male patients were included in the study; 22 had AN, 25 BN, and 26 BED. Patients with AN reported consuming 55% NOVA-4 foods, as opposed to approximately 70% in BN and BED patients. Foods that were consumed in a binge pattern were 100% ultra-processed.

CONCLUSION

Further research into the metabolic and neurobiological effects of ultra-processed food intake on disordered eating, particularly on binging, is needed.

The Western diet: a blind spot of eating disorder research?-a narrative review and recommendations for treatment and research

Over the last 50 years, in parallel with the obesity epidemic, the prevalence of eating disorders has increased and presentations have changed. In this narrative review, we consider recent research exploring the implications of changing patterns of food consumption on metabolic and neurobiological pathways, a hitherto neglected area in eating disorder research. One of the major changes over this time has been the introduction of ultra-processed (NOVA-4) foods, which are gradually replacing unprocessed and minimally processed foods. This has resulted in the increased intake of various sugars and food additives worldwide, which has important metabolic consequences: triggering insulin and glucose response, stimulating appetite, and affecting multiple endocrine and neurobiological pathways, as well as the microbiome. A paradigm shift is needed in the conceptual framework by which the vulnerability to, and maintenance of, different eating disorders may be understood, by integrating recent knowledge of the individual metabolic responses to modern highly processed foods into existing psychological models. This could stimulate research and improve treatment outcomes.

Lower Postprandial Thermogenic Response to an Unprocessed Whole Food Meal Compared to an Iso-Energetic/Macronutrient Meal Replacement in Young Women: A Single-Blind Randomized Cross-Over Trial

In contrast to ultra-processed foods that are associated with increased weight gain and obesity risk, nutritionally engineered dietary supplements, including meal replacement (MR) bars and shakes, are generally promoted as healthy. Limited data is available comparing the metabolic and hunger responses of whole food (WF) versus MR meals. The purpose of this study was to directly compare the thermic effect (TEM), respiratory exchange ratio (RER), hunger/taste ratings, and glucose response of two different breakfast meals containing MR and WF products in young healthy women. Eight volunteers completed two iso-caloric (529 kcals)/macronutrient (50% carbohydrates; 26% fat; 24% protein) test meals in a single-blind, randomized crossover design: (1) whole food meal; or (2) meal replacement. TEM was significantly higher following MR compared with WF (percent mean difference: 7.76 ± 3.78%; absolute mean difference: 0.053 ± 0.026 kcal/minute, p = 0.048), whereas WF substrate utilization demonstrated lower carbohydrate oxidation (RER) than MR (mean difference: -0.024 ± 0.008, p = 0.005). No differences existed for blood glucose response and feelings of hunger, desire to eat, and satiety among trials. Consumption of an MR meal increases postprandial thermogenesis and RER compared to a WF meal, which may impact weight control and obesity risk over the long-term.