Energy balance and obesity: a UK perspective on the gluttony v. sloth debate

Body and Fat mass are not Regulated, Controlled, or Defended: An introduction to the Invisible Hand' and 'Competition' Models of Metabolism

This paper presents two inter-dependent frameworks for understanding the etiology of obesity and the regain of body and fat mass after weight loss. The 'Invisible Hand of Metabolism' illustrates how physiologic states such as body and fat mass and blood glucose levels arise from the unregulated, uncontrolled, yet competitive behavior of trillions of semi-autonomous cells. The 'Competition Model of Metabolism' is an explanatory (mechanistic) framework that details how organismal and cell-specific behaviors generate the apparent stability of physiologic states despite metabolic perturbations (e.g., weight-loss and exercise). Together, these frameworks show that body and fat mass and blood glucose levels are not regulated, controlled, or defended but emerge from the complexity and functional plasticity of competitive cellular relations. Therefore, we argue that the use of abstract constructs such as 'regulation', 'control', 'glucostats', 'adipostats', and 'set-/settling-points' hinders the understanding of obesity and cardiometabolic diseases in human and nonhuman mammals.

Relationship between Regular Leisure-Time Physical Activity and Underweight and Overweight Status in Taiwanese Young Adults: A Cross-Sectional Study

The aim of this study was to determine the association between regular leisure-time physical activity (LTPA) and various body mass index (BMI) categories in Taiwanese young adults. A total of 10,802 young adults (18−44 years) were enrolled in a national telephone survey. The questionnaire data from this survey included socio-demographic characteristics, zip code of residence, LTPA behaviors, self-reported health status, and self-evaluated anthropometric measurements, which included height, body weight, and BMI. Regular and non-regular LTPA behaviors were defined as follows: (1) Regular LTPA: participants who reported breathing quickly and sweating when participating in 150−300 min per week of moderate-intensity LTPA or 75−150 min per week of vigorous-intensity LTPA. (2) Non-regular LTPA: the rest of the participants. The various BMI categories were defined as (1) underweight (BMI < 18.5 kg/m2), (2) normal weight (18.5 ≤ BMI < 24 kg/m2), (3) overweight (24 ≤ BMI < 27 kg/m2), and (4) obese (BMI ≥ 27 kg/m2). When compared with participants with non-regular LTPA, participants with regular LTPA exhibited lower risks of being overweight (odds ratio [OR], 0.837; 95% confidence interval [CI] 0.738−0.948) and underweight (OR, 0.732; 95% CI 0.611−0.876). However, there was no significant relationship between regular LTPA and obesity risk when using non-regular LTPA as the baseline after adjusting for potential confounders. The study results revealed that regular LTPA effectively reduced the risks of being underweight and overweight. However, for people with obesity, regular LTPA was unable to significantly decrease their obesity risk.

Competing paradigms of obesity pathogenesis: energy balance versus carbohydrate-insulin models

The obesity pandemic continues unabated despite a persistent public health campaign to decrease energy intake (“eat less”) and increase energy expenditure (“move more”). One explanation for this failure is that the current approach, based on the notion of energy balance, has not been adequately embraced by the public. Another possibility is that this approach rests on an erroneous paradigm. A new formulation of the energy balance model (EBM), like prior versions, considers overeating (energy intake > expenditure) the primary cause of obesity, incorporating an emphasis on “complex endocrine, metabolic, and nervous system signals” that control food intake below conscious level. This model attributes rising obesity prevalence to inexpensive, convenient, energy-dense, “ultra-processed” foods high in fat and sugar. An alternative view, the carbohydrate-insulin model (CIM), proposes that hormonal responses to highly processed carbohydrates shift energy partitioning toward deposition in adipose tissue, leaving fewer calories available for the body’s metabolic needs. Thus, increasing adiposity causes overeating to compensate for the sequestered calories. Here, we highlight robust contrasts in how the EBM and CIM view obesity pathophysiology and consider deficiencies in the EBM that impede paradigm testing and refinement. Rectifying these deficiencies should assume priority, as a constructive paradigm clash is needed to resolve long-standing scientific controversies and inform the design of new models to guide prevention and treatment. Nevertheless, public health action need not await resolution of this debate, as both models target processed carbohydrates as major drivers of obesity.

Obese individuals do not underreport dietary intake to a greater extent than nonobese individuals when data are allometrically‐scaled

Objective

The aim of this study was to assess the extent of misreporting in obese and nonobese adults on an absolute, ratio‐scaled, and allometrically‐scaled basis.

Method

Self‐reported daily energy intake (EI) was compared with total energy expenditure (TEE) in 221 adults (106 male, 115 female; age 53 ± 17 years, stature 1.68 ± 0.09 m, mass 79.8 ± 17.2 kg) who participated in a doubly‐labeled water (DLW) subsection of 2013–2015 National Diet and Nutrition Survey. Data were log transformed and expressed as absolute values, according to simple ratio‐standards (per kg body mass) and adjusted for body mass allometrically. Absolute and ratio‐scaled misreporting were examined using full‐factorial General Linear Models with repeated measures of the natural logarithms of TEE or EI as the within‐subjects factor. The natural logarithm of body mass was included as a covariate in the allometric method. The categorical variables of gender, age, obesity, and physical activity level (PAL) were the between‐factor variables.

Results

On an absolute‐basis, self‐reported EI (2759 ± 590 kcal·d⁻¹) was significantly lower than TEE measured by DLW (2759 ± 590 kcal·d⁻¹: F_1,205 = 598.81, p < .001, η_p² =0.75). We identified significantly greater underreporting in individuals with an obese BMI (F_1,205 = 29.01, p <.001, η_p² =0.12), in more active individuals (PAL > 1.75; F_1,205 = 34.15, p <.001, η_p² =0.14) and in younger individuals (≤55 years; F_1,205 = 14.82, p < .001, η_p² =0.07), which are all categories with higher energy needs. Ratio‐scaling data reduced the effect sizes. Allometric‐scaling removed the effect of body mass (F_1,205 =0.02, p = 0.887, η_p² =0.00).

Conclusion

In weight‐stable adults, obese individuals do not underreport dietary intake to a greater extent than nonobese individuals. These results contradict previous research demonstrating that obesity is associated with a greater degree of underreporting.

Challenges in tackling energy expenditure as obesity therapy: From preclinical models to clinical application

BACKGROUND

A chronic imbalance of energy intake and energy expenditure results in excess fat storage. The obesity often caused by this overweight is detrimental to the health of millions of people. Understanding both sides of the energy balance equation and their counter-regulatory mechanisms is critical to the development of effective therapies to treat this epidemic.

SCOPE OF REVIEW

Behaviors surrounding ingestion have been reviewed extensively. This review focuses more specifically on energy expenditure regarding bodyweight control, with a particular emphasis on the organs and attractive metabolic processes known to reduce bodyweight. Moreover, previous and current attempts at anti-obesity strategies focusing on energy expenditure are highlighted. Precise measurements of energy expenditure, which consist of cellular, animal, and human models, as well as measurements of their translatability, are required to provide the most effective therapies.

MAJOR CONCLUSIONS

A precise understanding of the components surrounding energy expenditure, including tailored approaches based on genetic, biomarker, or physical characteristics, must be integrated into future anti-obesity treatments. Further comprehensive investigations are required to define suitable treatments, especially because the complex nature of the human perspective remains poorly understood.

Nutritional Implications of Trade-Offs Between Fresh and Processed Potato Products in the United Kingdom (UK)

The UK ranks eleven among world potato producing countries with annual per capita production of about 102 kg. Since 2007, the price of potatoes has increased by 44 per cent and UK households have shown a decreasing trend on their purchases of potatoes. At the same time, retailers and manufacturers have been introducing processed potato products, which also has affected the demand for fresh potatoes. This has shifted demand from fresh potatoes to processed potatoes suggesting that consumers substitute fresh potatoes for processed ones. However, the extent to which this affect individual weekly nutritional composition is unknown. The objective of this study is to estimate the nutritional trade-offs between fresh and processed potatoes consumed in the UK using home scanner panel dataset for Great Britain in 2018. Price and expenditure elasticities were estimated using the linearized version of the Exact Affine Stone Index (EASI) Demand System. Using estimated elasticities, we analyzed the implications of substituting fresh potatoes for processed potatoes on nutrient intake. The results, in terms of the degree of substitution between fresh potatoes and processed potato products, suggest that consumers consider new potatoes baby and baking potatoes as substitutes for mashed potatoes. Maris piper potatoes and new potatoes baby are substitutes for frozen chips and other potatoes whilst white old potatoes and other vegetables and salads are complements to frozen chips and other potatoes. Finally, price reductions in the processed potatoes will increase average weekly caloric intake as well as the intakes of saturated fat and sodium. The latter has implications for public health as they are the major causes of cardiovascular diseases and certain cancers.

Metabolic adaptations during negative energy balance and their potential impact on appetite and food intake

This review examines the metabolic adaptations that occur in response to negative energy balance and their potential putative or functional impact on appetite and food intake. Sustained negative energy balance will result in weight loss, with body composition changes similar for different dietary interventions if total energy and protein intake are equated. During periods of underfeeding, compensatory metabolic and behavioural responses occur that attenuate the prescribed energy deficit. While losses of metabolically active tissue during energy deficit result in reduced energy expenditure, an additional down-regulation in expenditure has been noted that cannot be explained by changes in body tissue (e.g. adaptive thermogenesis). Sustained negative energy balance is also associated with an increase in orexigenic drive and changes in appetite-related peptides during weight loss that may act as cues for increased hunger and food intake. It has also been suggested that losses of fat-free mass (FFM) could also act as an orexigenic signal during weight loss, but more data are needed to support these findings and the signalling pathways linking FFM and energy intake remain unclear. Taken together, these metabolic and behavioural responses to weight loss point to a highly complex and dynamic energy balance system in which perturbations to individual components can cause co-ordinated and inter-related compensatory responses elsewhere. The strength of these compensatory responses is individually subtle, and early identification of this variability may help identify individuals that respond well or poorly to an intervention.

Unique associations of the Job Demand-Control-Support model subscales with leisure-time physical activity and dietary energy intake

Leisure-time physical activity (LTPA) and dietary energy intake are two important health behaviours, which at too low or high levels respectively, are associated with overweight and obesity. This study explores associations between subscales of the Job Demand-Control-Support (JDCS) model, LTPA and dietary energy intake. A cross-sectional design sampled current employees (N=433) from a South Australian cohort using a computer-assisted telephone interview and a self-completed food frequency questionnaire. In analyses adjusted for sex, age, and sociodemographic variables, higher levels of skill discretion were associated with increased odds for attaining sufficient physical activity (OR=2.45; 95% CI=1.10-5.47). Higher levels of decision authority were associated with reduced odds (OR=0.43; 95% CI=0.20-0.93) for being in the highest tertile of daily energy intake. Higher scores for coworker support were associated with increased odds (OR=2.20; 95% CI=1.15-4.23) for being in the highest tertile of daily energy intake. These findings support the consideration of the individual JDCS subscales, since this practice may reveal novel associations with health behaviour outcomes, thereby presenting new opportunities to improve employee health and wellbeing.

Why are women slimmer than men in developed countries?

Women have a lower BMI than men in developed countries, yet the opposite is true in developing countries. We call this the gender BMI puzzle and investigate its underlying cause. We begin by studying time trends in Japan, where, consistent with the cross-country puzzle, the BMI of adult women has steadily decreased since the 1950s, whereas the BMI of adult men has steadily increased. We study how changes in energy intake and energy expenditure account for the over-time gender BMI puzzle using the Japanese National Nutrition Survey from 1975 to 2010, which provides nurse-measured height and weight and nutritionist-assisted food records. Because long-term data on energy expenditure do not exist, we calculate energy expenditure using a steady-state body weight model. We then conduct cross-country regression analysis to corroborate what we learn from the Japanese data. We find that both energy intake and energy expenditure have significantly decreased for Japanese adult men and women and that a larger reduction in energy expenditure among men than women accounts for the increasing male-to-female BMI gap. Trends in BMI and energy expenditure vary greatly by occupation, suggesting that a relatively large decrease in physical activity in the workplace among men underlies the gender BMI puzzle. The cross-country analysis supports the generalizability of the findings beyond the Japanese data. Furthermore, the analysis suggests the increasing male-to-female BMI gap is driven not only by a reduction in the energy requirements of physically demanding work but also by weakening occupational gender segregation. No support is found for other explanations, such as increasing female labor force participation, greater female susceptibility to malnutrition in utero, and gender inequality in nutrition in early life.

Assessing national nutrition security: The UK reliance on imports to meet population energy and nutrient recommendations

Nutrition security describes the adequacy of the food supply to meet not only energy but also macronutrient and micronutrient requirements for the population. The aim of this study was to develop a method to assess trends in national nutrition security and the contribution of imports to nutrition security, using the UK as a case study. Food supply data from FAO food balance sheets and national food composition tables were used to estimate the nutrient content of domestically produced food, imported food and exported food. Nutrition security was defined as the total nutrient supply (domestic production, minus exports, plus imports) to meet population-level nutrient requirements. The results showed that the UK was nutrition secure over the period 1961–2011 for energy, macronutrients and key micronutrients, with the exception of total carbohydrates and fibre, which may be due to the loss of fibre incurred by processing cereals into refined products. The supply of protein exceeded population requirements and could be met with domestic production alone. Even excluding all meat there was sufficient protein for population requirements. The supply of total fat, saturated fat and sugar considerably exceeded the current dietary recommendation. As regards nutrition security in 2010, the UK was reliant on imported foods to meet energy, fibre, total carbohydrate, iron, zinc and vitamin A requirements. This analysis demonstrates the importance of including nutrients other than energy to determine the adequacy of the food supply. The methodology also provides an alternative perspective on food security and self-sufficiency by assessing the dependency on imports to meet population level nutritional requirements.

Buying less and wasting less food. Changes in household food energy purchases, energy intakes and energy density between 2007 and 2012 with and without adjustment for food waste

Objective

Consumers in the UK responded to the rapid increases in food prices between 2007 and 2009 partly by reducing the amount of food energy bought. Household food and drink waste has also decreased since 2007. The present study explored the combined effects of reductions in food purchases and waste on estimated food energy intakes and dietary energy density.

Design

The amount of food energy purchased per adult equivalent was calculated from Kantar Worldpanel household food and drink purchase data for 2007 and 2012. Food energy intakes were estimated by adjusting purchase data for food and drink waste, using waste factors specific to the two years and scaled for household size.

Setting

Scotland.

Subjects

Households in Scotland (n 2657 in 2007; n 2841 in 2012).

Results

The amount of food energy purchased decreased between 2007 and 2012, from 8·6 to 8·2 MJ/adult equivalent per d (P<0·001). After accounting for the decrease in food waste, estimated food energy intake was not significantly different (7·3 and 7·2 MJ/adult equivalent per d for 2007 and 2012, respectively; P=0·186). Energy density of foods purchased increased slightly from 700 to 706 kJ/100 g (P=0·010).

Conclusions

While consumers in Scotland reduced the amount of food energy that they purchased between 2007 and 2012, this was balanced by reductions in household food and drink waste over the same time, resulting in no significant change in net estimated energy intake of foods brought into the home.

The Validity of US Nutritional Surveillance: USDA's Loss-Adjusted Food Availability Data Series 1971-2010

The purpose of this study was to examine the validity of the 1971-2010 United States Department of Agriculture's (USDA's) loss-adjusted food availability (LAFA) per capita caloric consumption estimates. Estimated total daily energy expenditure (TEE) was calculated for nationally representative samples of US adults, 20-74 years, using the Institute of Medicine's predictive equations with "low-active" (TEE L-ACT) and "sedentary" (TEE SED) physical activity values. TEE estimates were subtracted from LAFA estimates to create disparity values (kcal/d). A validated mathematical model was applied to calculate expected weight change in reference individuals resulting from the disparity. From 1971-2010, the disparity between LAFA and TEE L-ACT varied by 394kcal/d-(P < 0.001), from -205kcal/d (95% CI: -214, -196) to +189kcal/d (95% CI: 168, 209). The disparity between LAFA and TEE SED varied by 412kcal/d (P < 0.001), from -84kcal/d (95% CI: -93, -76) to +328kcal/d (95% CI: 309, 348). Our model suggests that if LAFA estimates were actually consumed, reference individuals would have lost ~1-4kg/y from 1971-1980 (an accumulated loss of ~12 to ~36kg), and gained ~3-7kg/y from 1988-2010 (an accumulated gain of ~42 to ~98kg). These estimates differed from the actual measured increments of 10kg and 9kg in reference men and women, respectively, over the 39-year period. The USDA LAFA data provided inconsistent, divergent estimates of per capita caloric consumption over its 39-year history. The large, variable misestimation suggests that the USDA LAFA per capita caloric intake estimates lack validity and should not be used to inform public policy.

Diet and exercise in uterine cancer survivors (DEUS pilot) - piloting a healthy eating and physical activity program: study protocol for a randomized controlled trial

BACKGROUND

Endometrial cancer survivors comprise a high-risk group for obesity-related comorbidities. Healthy eating and physical activity can lead to better health and well-being, but this population may experience difficulties adopting healthy lifestyle practices. Personalised behaviour change programmes that are feasible, acceptable and cost-effective are needed. The aim of this trial is to pilot a manualised programme about healthy eating and physical activity.

METHODS/DESIGN

This is a phase II, individually randomized, parallel, controlled, two-site, pilot clinical trial. Adult endometrial cancer survivors (n = 64) who have been diagnosed with endometrial cancer within the previous 3 years and are not on active treatment will be invited to participate. Participants will be assigned in a 1:1 ratio through minimisation to either an 8-week, group-based, behaviour-change programme with weekly 90-min sessions about healthy eating and physical activity or usual care. The intervention will focus on self-monitoring, goal setting and self-rewards. Follow-up assessments will be conducted at 8 and 24 weeks from the baseline assessment. Primary feasibility outcomes will include rates of recruitment, adherence, and retention.

DISCUSSION

The study results will inform the development of a definitive randomised controlled trial to test if the programme can improve the health and quality of life of this population. It will also provide guidance on costing the intervention and the health care resource use in this population.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02433080, 20 April 2015.

A critical examination of the available data sources for estimating meat and protein consumption in the USA

OBJECTIVE

To describe the methods, strengths and limitations of available data sources for estimating US meat and protein consumption in order to facilitate accurate interpretations and applications.

DESIGN

We examined agricultural supply and dietary intake databases from the US Department of Agriculture (USDA), the US Department of Health and Human Services and the FAO to describe their methodology and to report the most recent estimates for meat and protein consumption.

RESULTS

Together, loss-adjusted agricultural supply data and dietary recall data provide the best available estimates of US consumption; the most recent sources indicated that US citizens (ages 2 years and over) consume 4·4-5·9 oz (125·9-166·5 g) of total meat and 6·2-7·4 oz-eq (175·2-209·4 g-eq) from the USDA Protein Foods Group per day. Meat constitutes the majority of intake within the Protein Foods Group, and red meat and processed meat constitute the majority of total meat intake. Nutrient supply data indicate that total meat represents an estimated 43·1 % of the total protein available in the US food supply, but without any loss-adjusted nutrient data, per capita protein intake is best estimated by dietary recall data to be 79·9 g/d.

CONCLUSIONS

In order to address public health concerns related to excess meat and/or protein consumption, practitioners, educators and researchers must appropriately use available data sources in order to accurately report consumption at the population level. Implications for comparing these estimates with various recommended intakes are discussed.

Growing healthy muscles to optimise metabolic health into adult life

The importance of skeletal muscle for metabolic health and obesity prevention is gradually gaining recognition. As a result, interventions are being developed to increase or maintain muscle mass and metabolic function in adult and elderly populations. These interventions include exercise, hormonal and nutritional therapies. Nonetheless, growing evidence suggests that maternal malnutrition and obesity during pregnancy and lactation impede skeletal muscle development and growth in the offspring, with long-term functional consequences lasting into adult life. Here we review the role of skeletal muscle in health and obesity, providing an insight into how this tissue develops and discuss evidence that maternal obesity affects its development, growth and function into adult life. Such evidence warrants the need to develop early life interventions to optimise skeletal muscle development and growth in the offspring and thereby maximise metabolic health into adult life.

A new model of the role of psychological and emotional distress in promoting obesity: conceptual review with implications for treatment and prevention

The lack of significant treatment and prevention progress highlights the need for a more expanded strategy. Given the robust association between socioeconomic factors and obesity, combined with new insights into how socioeconomic disadvantage affects both behaviour and biology, a new causal model is proposed. The model posits that psychological and emotional distress is a fundamental link between socioeconomic disadvantage and weight gain. At particular risk are children growing up in a disharmonious family environment, mainly caused by parental socioeconomic disadvantage, where they are exposed to parental frustrations, relationship discord, a lack of support and cohesion, negative belief systems, unmet emotional needs and general insecurity. Without adequate resilience, such experiences increase the risk of psychological and emotional distress, including low self-esteem and self-worth, negative emotions, negative self-belief, powerlessness, depression, anxiety, insecurity and a heightened sensitivity to stress. These inner disturbances eventually cause a psycho-emotional overload, triggering a cascade of weight gain-inducing effects including maladaptive coping strategies such as eating to suppress negative emotions, chronic stress, appetite up-regulation, low-grade inflammation and possibly reduced basal metabolism. Over time, this causes obesity, circular causality and further weight gain. Tackling these proposed root causes of weight gain could potentially improve both treatment and prevention outcomes.

Obscurity on obesity

Much research is underway on the links between diet and obesity. So too are long-running disputes among nutritionists on core questions about the relationship. This editorial reviews the state-of-play on four issues: what makes people fat, how to lose weight, how much do we eat, and what policies to adopt towards obesity. The practical consequence is that, at present, frontline health professionals will not find in nutrition science agreed, actionable solutions to assist overweight patients. But research and debate continues actively.

Energy gap in the aetiology of body weight gain and obesity: a challenging concept with a complex evaluation and pitfalls

The concept of energy gap(s) is useful for understanding the consequence of a small daily, weekly, or monthly positive energy balance and the inconspicuous shift in weight gain ultimately leading to overweight and obesity. Energy gap is a dynamic concept: an initial positive energy gap incurred via an increase in energy intake (or a decrease in physical activity) is not constant, may fade out with time if the initial conditions are maintained, and depends on the 'efficiency' with which the readjustment of the energy imbalance gap occurs with time. The metabolic response to an energy imbalance gap and the magnitude of the energy gap(s) can be estimated by at least two methods, i.e. i) assessment by longitudinal overfeeding studies, imposing (by design) an initial positive energy imbalance gap; ii) retrospective assessment based on epidemiological surveys, whereby the accumulated endogenous energy storage per unit of time is calculated from the change in body weight and body composition. In order to illustrate the difficulty of accurately assessing an energy gap we have used, as an illustrative example, a recent epidemiological study which tracked changes in total energy intake (estimated by gross food availability) and body weight over 3 decades in the US, combined with total energy expenditure prediction from body weight using doubly labelled water data. At the population level, the study attempted to assess the cause of the energy gap purported to be entirely due to increased food intake. Based on an estimate of change in energy intake judged to be more reliable (i.e. in the same study population) and together with calculations of simple energetic indices, our analysis suggests that conclusions about the fundamental causes of obesity development in a population (excess intake vs. low physical activity or both) is clouded by a high level of uncertainty.