Ad libitum meal energy intake is positively influenced by energy density, eating rate and hyper-palatable food across four dietary patterns

Obesity- and diet-induced plasticity in systems that control eating and energy balance

In April 2023, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), in partnership with the National Institute of Child Health and Human Development, the National Institute on Aging, and the Office of Behavioral and Social Sciences Research, hosted a 2-day online workshop to discuss neural plasticity in energy homeostasis and obesity. The goal was to provide a broad view of current knowledge while identifying research questions and challenges regarding neural systems that control food intake and energy balance. This review includes highlights from the meeting and is intended both to introduce unfamiliar audiences with concepts central to energy homeostasis, feeding, and obesity and to highlight up-and-coming research in these areas that may be of special interest to those with a background in these fields. The overarching theme of this review addresses plasticity within the central and peripheral nervous systems that regulates and influences eating, emphasizing distinctions between healthy and disease states. This is by no means a comprehensive review because this is a broad and rapidly developing area. However, we have pointed out relevant reviews and primary articles throughout, as well as gaps in current understanding and opportunities for developments in the field.

Analytical approaches for assessing protein structure in protein-rich food: A comprehensive review

This review focuses on changes in nutrition and functional properties of protein-rich foods, primarily attributed to alterations in protein structures. We provide a comprehensive overview and comparison of commonly used laboratory methods for protein structure identification, aiming to offer readers a convenient understanding of these techniques. The review covers a range of detection technologies employed in food protein analysis and conducts an extensive comparison to identify the most suitable method for various proteins. While these techniques offer distinct advantages for protein structure determination, the inherent complexity of food matrices presents ongoing challenges. Further research is necessary to develop and enhance more robust detection methods to improve accuracy in protein conformation and structure analysis.

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.

"Mindset Matters": Perseverance, a balanced approach and structured support as facilitators of whole foods plant-based adoption

Whole foods plant-based diets (WFPBD) show potential for preventing and addressing chronic diseases. However, concerns exist about their acceptability and feasibility. Research on firsthand WFPBD adoption experiences is limited but crucial for promoting dietary change. In a 12-week remotely delivered lifestyle modification program using an ad libitum WFPBD, twenty weight-loss seeking adults (ages 18-75) with overweight or obesity completed self-report surveys and semi-structured interviews via Zoom. The study aimed to explore: (1) experiences with WFPBD adoption; (2) factors that helped or hindered adherence; and (3) perceived salient benefits. Interviews were analyzed inductively through a conventional content analysis, and associations between variables examined with correlational analyses. Participants overall reported WFPBD adoption being a positive, new experience, with an equal number (30%) finding it easy/easier than expected as challenging. Key cited challenges included overwhelm, different eating habits in the household, and meal preparation. Key cited facilitators included adopting an incremental approach to dietary change, persisting after setbacks, and having simple go-to meals. Greater self-compassion and family support, and less sabotage from friends and family corresponded to greater dietary change (rs > 0.45, ps < .05). Participants valued accountability, structure, human support, nutrition psychoeducation and recipes in the program. Three categories emerged regarding perceived benefits of following the WFPBD: physical health benefits, improvements to eating habits, and greater perceived control/agency over health. Results indicate that future interventions should include psychological strategies alongside nutrition education to enhance self-efficacy, address household barriers, and combat feelings of overwhelm through sufficient structure, support, and meal preparation guidance. Messaging around WFPBD may benefit from discussing prevailing positive experiences with adoption, common benefits experienced, and options for an incremental approach given that feasibility and acceptability concerns may deter efforts.

Ultra-processed Food and Obesity: What Is the Evidence?

PURPOSE OF REVIEW

Obesity is a growing global healthcare concern. A proposed driver is the recent increase in ultra-processed food (UPF) intake. However, disagreement surrounds the concept of UPF, the strength of evidence, and suggested mechanisms. Therefore, this review aimed to critically appraise the evidence on UPF and obesity.

RECENT FINDINGS

Observational studies demonstrate positive associations between UPF intake, weight gain, and overweight/obesity, more clearly in adults than children/adolescents. This is supported by high-quality clinical data. Several mechanisms are proposed, but current understanding is inconclusive. Greater UPF consumption has been a key driver of obesity. There is a need to change the obesogenic environment to support individuals to reduce their UPF intake. The UPF concept is a novel approach that is not explained with existing nutrient- and food-based frameworks. Critical analysis of methodologies provides confidence, but future observational and experimental research outputs with greater methodological rigor will strengthen findings, which are outlined.

Giving fruits and vegetables a tax break: lessons from a Dutch attempt

OBJECTIVE

Food taxation can improve diets by making unhealthy foods more expensive and by making healthy foods cheaper. In the Netherlands, a political window of opportunity arose in December 2021 to reduce the value-added tax (VAT) on fruits and vegetables to zero percent. The policy is now facing institutional friction along several fronts, however, delaying and potentially averting its implementation. We analysed this institutional friction to inform future food tax policies.

DESIGN

We qualitatively analysed open-access fiscal and health experts' position papers about benefits and downsides of the zero-rate that were discussed with members of parliament in June 2023.

SETTING

The Netherlands.

PARTICIPANTS

Not applicable.

RESULTS

Health and fiscal experts expressed noticeably different viewpoints towards the utility of the zero-rate. One important argument fiscal experts based their negative advice upon pertained to the legal restrictions for distinguishing between healthier and unhealthier forms of fruits and vegetables (i.e. the principle of neutrality). A zero-rate VAT on unhealthier forms of fruits and vegetables, e.g. processed cucumber, mixed with salt and sugar, would be undesirable, but differentiating between raw and processed cucumber would offend the neutrality principle.

CONCLUSIONS

The Dutch attempt to give fruits and vegetables a tax break highlights the need for crystal-clear food classifications when designing food tax policies. Public health nutritionists should combine classifications based on caloric density, palatability, degree of processing and nutrient content to provide a database for evidence-informed tax differentiation according to food item healthfulness.

Evidence that carbohydrate-to-fat ratio and taste, but not energy density or NOVA level of processing, are determinants of food liking and food reward

This virtual (online) study tested the common but largely untested assumptions that food energy density, level of processing (NOVA categories), and carbohydrate-to-fat (CF) ratio are key determinants of food reward. Individual participants (224 women and men, mean age 35 y, 53% with healthy weight, 43% with overweight or obesity) were randomised to one of three, within-subjects, study arms: energy density (32 foods), or level of processing (24 foods), or CF ratio (24 foods). They rated the foods for taste pleasantness (liking), desire to eat (food reward), and sweetness, saltiness, and flavour intensity (for analysis averaged as taste intensity). Against our hypotheses, there was not a positive relationship between liking or food reward and either energy density or level of processing. As hypothesised, foods combining more equal energy amounts of carbohydrate and fat (combo foods), and foods tasting more intense, scored higher on both liking and food reward. Further results were that CF ratio, taste intensity, and food fibre content (negatively), independent of energy density, accounted for 56% and 43% of the variance in liking and food reward, respectively. We interpret the results for CF ratio and fibre in terms of food energy-to-satiety ratio (ESR), where ESR for combo foods is high, and ESR for high-fibre foods is low. We suggest that the metric of ESR should be considered when designing future studies of effects of food composition on food reward, preference, and intake.

US tobacco companies selectively disseminated hyper-palatable foods into the US food system: Empirical evidence and current implications

BACKGROUND AND AIMS

US tobacco companies owned leading US food companies from 1980 to 2001. We measured whether hyper-palatable foods (HPF) were disproportionately developed in tobacco-owned food companies, resulting in substantial tobacco-related influence on the US food system.

DESIGN

The study involved a review of primary industry documents to identify food brands that were tobacco company-owned. Data sets from the US Department of Agriculture were integrated to facilitate longitudinal analyses estimating the degree to which foods were formulated to be hyper-palatable, based on tobacco ownership.

SETTING AND CASES

United States Department of Agriculture data sets were used to identify HPF foods that were (n = 105) and were not (n = 587) owned by US tobacco companies from 1988 to 2001.

MEASUREMENTS

A standardized definition from Fazzino et al. (2019) was used to identify HPF. HPF items were identified overall and by HPF group: fat and sodium HPF, fat and sugar HPF and carbohydrates and sodium HPF.

FINDINGS

Tobacco-owned foods were 29% more likely to be classified as fat and sodium HPF and 80% more likely to be classified as carbohydrate and sodium HPF than foods that were not tobacco-owned between 1988 and 2001 (P-values = 0.005-0.009). The availability of fat and sodium HPF (> 57%) and carbohydrate and sodium HPF (> 17%) was high in 2018 regardless of prior tobacco-ownership status, suggesting widespread saturation into the food system.

CONCLUSIONS

Tobacco companies appear to have selectively disseminated hyper-palatable foods into the US food system between 1988 and 2001.

The prevalence of hyperpalatable food intake among individuals with food addiction seeking bariatric surgery

INTRODUCTION

The prevalence of food addiction among patients seeking bariatric surgery is approximately 30 %. While hyper-palatable foods (HPF) have been identified as the potential 'substance' in food addiction and a contributor to severe obesity, consumption of HPF among individuals with food addiction, including those seeking bariatric surgery, is unknown. Thus, the aim of this study was to evaluate the consumption of HPF among individuals seeking bariatric surgery with food addiction, compared to those without food addiction.

METHODS

Participants were N = 54 individuals with severe obesity seeking bariatric surgery. The Yale Food Addiction Scale was used to identify individuals with food addiction (FA) (37 % of sample). Dietary recalls were used to quantify HPF intake. Analyses were conducted to characterize average HPF intake and to determine whether there were significant differences between HPF intake among those with FA compared to those without FA, and whether HFP intake was correlated with FA symptoms.

RESULTS

On average, 71 % of participants' daily calorie intake was from HPF. There were no significant differences in HPF items intake among individuals with and without FA (70.46 % vs 71.34; p = 0.85). A positive correlation between number of FA symptoms and the intake of HPF high in fat and sugar ([0.3]; p = 0.03) was observed.

CONCLUSION

In this pilot study, HPF consumption among individuals with and without FA seeking bariatric surgery was high overall, however there were no differences across groups. In addition, intake of HPF with fat and sugar was associated with the number of symptoms of food addiction. More studies with a larger sample are needed to confirm these preliminary findings.

Motives and food craving: Associations with frequency of hyper-palatable food intake among college students

BACKGROUND

College food environments provide wide access to hyper-palatable foods (HPF). Palatable eating motives and craving are individual factors that may impact HPF intake. Nevertheless, no study to date has examined the relationship between these factors and frequency of HPF intake in a dormitory all-you-can-eat-style cafeteria meal, a typical college food setting.

METHODS

College students (N = 218) self-reported frequency of HPF intake at a college cafeteria meal and their frequency of HPF intake in the overall diet. Quasipoisson and logistic regression models tested whether palatable eating motives (assessed via the Palatable Eating Motives Scale) and craving (assessed via the Food Craving Inventory) were associated with the rate of HPF intake during the cafeteria meal and excess frequency of HPF intake in the overall diet.

RESULTS

Craving was associated with a 19% higher rate of HPF intake during the cafeteria meal (RR = 1.19; p = .015) and a >2-fold higher likelihood of excess frequency of HPF intake the overall diet (OR = 2.69; p < .001). Coping motive was associated with an 87% higher likelihood of excess frequency of HPF intake in the overall diet (OR = 1.87; p = .002), but not in the cafeteria meal. Reward enhancement, social and conformity motives were not significantly associated with the frequency of HPF intake in either setting.

CONCLUSIONS

Results highlight the role of craving and coping motive in the frequency of HPF intake among college students. Prevention efforts may consider targeting craving and eating to cope to potentially address frequency of HPF intake among college students.

Eating out intensity, ultra-processed foods and BMI among Albanian youth

OBJECTIVE

Ultra-processed foods (UPF) and eating out of home (OH) are changing nutrition, particularly among youth in constrained settings. We aimed to assess the role of eating OH intensity on the associations of UPF and unprocessed or minimally processed foods (UMPF) with BMI among Albanian youth.

DESIGN

Cross-sectional.

SETTING

Albania, a south-eastern European country.

PARTICIPANTS

281 youth, predominantly females.

METHODS

UPF and UMPF were defined based on NOVA, while eating OH intensity based on energy percentage from OH foods. Multivariable models tested associations of UPF and UMPF with BMI stratified by eating OH intensity, controlled for relevant covariates including diet quality, portion size and costs.

RESULTS

The respondents age ranged between 18 and 23 years with a female predominance (87·5 %). Mean energy from UPF and UMPF was 846 (sd: 573·0) and 802·9 (422·5) kcals, respectively. Among substantial at home eaters UPF intake was not associated (β = −0·07, 95 % CI (−0·13, 0·267)) with BMI; however, UMPF negatively associated with BMI (β = −0·24, 95 % CI (−0·43, −0·06)). Among those defined as substantial OH eaters, UPF (β = 0·24, 95 % CI (0·08, 0·40)) and UMPF (β = 0·18, 95 % CI (0·04, 0·33)) were positively associated with BMI.

CONCLUSIONS

Our findings provide evidence for the hypothesis that eating OH plays an important role in the association of UPF and UMPF with BMI in youth. While causality cannot be established due to cross-sectional design, to the best of our knowledge, we provide the first assessment of UPF and UMPF intake in a south-eastern European setting, while highlighting the need for establishing and integrating youth nutrition into national nutritional surveillance systems for key dietary risk factors in Albania.

Perspective: A Research Roadmap about Ultra-Processed Foods and Human Health for the United States Food System: Proceedings from an Interdisciplinary, Multi-Stakeholder Workshop

Our objective was to convene interdisciplinary experts from government, academia, and industry to develop a Research Roadmap to identify research priorities about processed food intake and risk for obesity and cardiometabolic diseases (CMD) among United States populations. We convened attendees at various career stages with diverse viewpoints in the field. We held a "Food Processing Primer" to build foundational knowledge of how and why foods are processed, followed by presentations about how processed foods may affect energy intake, obesity, and CMD risk. Breakout groups discussed potential mechanistic and confounding explanations for associations between processed foods and obesity and CMD risk. Facilitators created research questions (RQs) based on key themes from discussions. Different breakout groups convened to discuss what is known and unknown for each RQ and to develop sub-RQs to address gaps. Workshop attendees focused on ultra-processed foods (UPFs; Nova Group 4) because the preponderance of evidence is based on this classification system. Yet, heterogeneity and subjectivity in UPF classification was a challenge for RQ development. The 6 RQs were: 1) What objective methods or measures could further categorize UPFs, considering food processing, formulation, and the interaction of the two? 2) How can exposure assessment of UPF intake be improved? 3) Does UPF intake influence risk for obesity or CMDs, independent of diet quality? 4) What, if any, attributes of UPFs influence ingestive behavior and contribute to excess energy intake? 5) What, if any, attributes of UPFs contribute to clinically meaningful metabolic responses? 6) What, if any, external environmental factors lead people to consume high amounts of UPFs? Uncertainty and complexity around UPF intake warrant further complementary and interdisciplinary causal, mechanistic, and methodological research related to obesity and CMD risk to understand the utility of applying classification by degree of processing to foods in the United States.

Discordance between gut-derived appetite hormones and energy intake in humans

Gut-derived hormones affect appetite and are thought to play an important role in body weight regulation. Dietary macronutrient composition can influence gut-derived appetite hormone concentrations, thereby providing theoretical basis for why some diets might facilitate weight loss better than others. We investigated postprandial gut-derived appetite hormones in 20 inpatient adults after 2 weeks of eating either a low carbohydrate (LC) or a low fat (LF) diet followed by the alternate diet in random order. A LC meal resulted in significantly greater postprandial GLP-1, GIP, and PYY but lower ghrelin compared to an isocaloric LF meal (all p≤0.02). However, differences in gut-derived appetite hormones were incommensurate with subsequent ad libitum energy intake over the rest of the day, which was 551±103 kcal (p<0.0001) greater with the LC as compared to the LF diet. The effects of gut-derived appetite hormones on ad libitum energy intake can be dominated by other diet-related factors, at least in the short-term.

Effects of ketone bodies on energy expenditure, substrate utilization, and energy intake in humans

The potential of ketogenic approaches to regulate energy balance has recently gained attention since ketones may influence both energy expenditure and energy intake. In this narrative review, we summarized the most relevant evidence about the role of ketosis on energy expenditure, substrate utilization, and energy intake in humans. We considered different strategies to induce ketosis, such as fasting, dietary manipulation, and exogenous ketone sources. In general, ketosis does not have a major influence on energy expenditure but promotes a shift in substrate utilization towards ketone body oxidation. The strategies to induce ketosis by reduction of dietary carbohydrate availability (e.g., ketogenic diets) do not independently influence energy intake, being thus equally effective for weight loss as diets with higher carbohydrate content. In contrast, the intake of medium-chain triglycerides and ketone esters induces ketosis and appears to increase energy expenditure and reduce energy intake in the context of high carbohydrate availability. These latter strategies lead to slightly enhanced weight loss. Unfortunately, distinguishing the effects of the various ketogenic strategies per se from the effects of other physiological responses is not possible with the available human data. Highly controlled, inpatient studies using targeted strategies to isolate the independent effects of ketones are required to adequately address this knowledge gap.

Breaking down silos: the multifaceted nature of obesity and the future of weight management

The continued global increase in the prevalence of obesity prompted a meeting at the Royal Society of London investigating causal mechanisms of the disease, 'Causes of obesity: theories, conjectures, and evidence' in October 2022. Evidence presented indicates areas of obesity science where there have been advancements, including an increased understanding of biological and physiological processes of weight gain and maintenance, yet it is clear there is still debate on the relative contribution of plausible causes of the modern obesity epidemic. Consensus was reached that obesity is not a reflection of diminished willpower, but rather the confluence of multiple, complex factors. As such, addressing obesity requires multifactorial prevention and treatment strategies. The accumulated evidence suggests that a continued focus primarily on individual-level contributors will be suboptimal in promoting weight management at the population level. Here, we consider individual biological and physiological processes within the broader context of sociodemographic and sociocultural exposures as well as environmental changes to optimize research priorities and public health efforts. This requires a consideration of a systems-level approach that efficiently addresses both systemic and group-specific environmental determinants, including psychosocial factors, that often serve as a barrier to otherwise efficacious prevention and treatment options. This article is part of a discussion meeting issue 'Causes of obesity: theories, conjectures and evidence (Part I)'.

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)'.

Does sourdough bread provide clinically relevant health benefits?

During the last decade, scientific interest in and consumer attention to sourdough fermentation in bread making has increased. On the one hand, this technology may favorably impact product quality, including flavor and shelf-life of bakery products; on the other hand, some cereal components, especially in wheat and rye, which are known to cause adverse reactions in a small subset of the population, can be partially modified or degraded. The latter potentially reduces their harmful effects, but depends strongly on the composition of sourdough microbiota, processing conditions and the resulting acidification. Tolerability, nutritional composition, potential health effects and consumer acceptance of sourdough bread are often suggested to be superior compared to yeast-leavened bread. However, the advantages of sourdough fermentation claimed in many publications rely mostly on data from chemical and in vitro analyzes, which raises questions about the actual impact on human nutrition. This review focuses on grain components, which may cause adverse effects in humans and the effect of sourdough microbiota on their structure, quantity and biological properties. Furthermore, presumed benefits of secondary metabolites and reduction of contaminants are discussed. The benefits claimed deriving from in vitro and in vivo experiments will be evaluated across a broader spectrum in terms of clinically relevant effects on human health. Accordingly, this critical review aims to contribute to a better understanding of the extent to which sourdough bread may result in measurable health benefits in humans.

Weight Loss Supplements

Being overweight or obese can predispose people to chronic diseases and metabolic disorders such as cardiovascular illnesses, diabetes, Alzheimer's disease, and cancer, which are costly public health problems and leading causes of mortality worldwide. Many people hope to solve this problem by using food supplements, as they can be self-prescribed, contain molecules of natural origin considered to be incapable of causing damage to health, and the only sacrifice they require is economic. The market offers supplements containing food plant-derived molecules (e.g., primary and secondary metabolites, vitamins, and fibers), microbes (probiotics), and microbial-derived fractions (postbiotics). They can control lipid and carbohydrate metabolism, reduce appetite (interacting with the central nervous system) and adipogenesis, influence intestinal microbiota activity, and increase energy expenditure. Unfortunately, the copious choice of products and different legislation on food supplements worldwide can confuse consumers. This review summarizes the activity and toxicity of dietary supplements for weight control to clarify their potentiality and adverse reactions. A lack of research regarding commercially available supplements has been noted. Supplements containing postbiotic moieties are of particular interest. They are easier to store and transport and are safe even for people with a deficient immune system.