Nutrition Publication

NNIW73 - Obesity Treatment and Prevention: New Directions

Editor(s): A. Drewnowski, B. Rolls. 73

Obesity remains a large public health issue. Therefore, the NNI dedicated a workshop entitled "Obesity Treatment and Prevention: New Directions" to the topic. Prof. A. Drewnowski and Prof. B. Rolls established an outstanding scientific program which is published in the PubMed indexed Nestlé Nutrition Institute Workshop book series.

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Concluding Remarks

Obesity remains a large public health issue. Therefore, the NNI dedicated a workshop entitled:  'Obesity Treatment and Prevention: New Directions' to the topic. Prof. A. Drewnowski and Prof. B. Rolls established an outstanding scientific program which is published in the PubMed indexed Nestlé Nutrition Institute Workshop book series.

Brain Reorganization following Weight Loss

Author(s): M. Rosenbaum

The long- term stability of bodyweight despite wide variation in energy intake and expenditure suggests that at usual weight energy intake and output are ‘coupled’ to maintain body energy stores. Our model for some of the molecular mechanics of this regulation of energy stores is based on the concept of a neurally encoded ‘threshold’ for minimum body fat, below which compensatory physiology is invoked to restore body fat. The existence of such a centrally encoded threshold is supported by the similarities in response to maintenance of a reduced weight between lean and obese individuals, and the tendency for weight- reduced individuals to regain weight to levels of fat stores similar to those present prior to initial weight loss. Brain responses to food and the observed changes in energy expenditure that occur during maintenance of a reduced weight are largely reversed by the administration of the adipocyte- derived hormone, leptin.

Physical Activity and Weight Loss

Author(s): J. Jakicic

Weight loss interventions involving diet and physical activity typically result in 8– 10% weight loss within 6– 12 months after initiating treatment. Physical activity is a key component of these interventions for a variety of reasons. Weight loss achieved with physical activity averages approximately 1– 3 kg, and the effects of physical activity on weight loss appear to be additive to what is observed with dietary restriction alone. Moreover, physical activity is an important behavior for prevention of weight regain and maintenance of significant weight loss resulting from dietary restriction, and physical activity contributes to weight loss in patients who have undergone bariatric surgery. However, there is significant interindividual variability in the weight loss resulting from physical activity, with both biological and behavioral factors contributing to this variability. Thus, additional research is needed to understand the role of physical activity in energy balance and body weight regulation, along with an understanding of the optimal intervention strategies to promote physical activity participation in overweight and obese individuals.

Dietary Strategies for Weight Management

Author(s): B. Rolls

In an ‘obesogenic’ environment, getting people to eat appropriate amounts is challenging. Several food- based strategies have the potential to promote satiety and moderate energy intake. Components of foods such as macronutrients and functional ingredients can affect satiety; however, for weight management a more comprehensive approach is needed that emphasizes behavioral strategies to improve the overall diet. Research shows that large portions of energy- dense foods facilitate overconsumption and that reductions in portion size and energy density are associated with reduced energy intake. While this suggests that people should eat smaller portions, recent data show that if people lower the energy density of their diet, they can continue to eat their usual amount of food while limiting calories. Furthermore, serving larger portions of low- energy- dense foods can be used strategically to encourage their consumption and reduce dietary energy density, and this has been shown to be associated with decreased energy intake while maintaining satiety. This new understanding of how portion size can be used positively to manage energy intake has the potential to help people achieve sustainable improvements in their energy intake and bodyweight. Science- based strategies that increase the availability of affordable nutrient- rich, lower energy- dense foods are urgently needed.

Targeting Adipose Tissue Inflammation to Treat the Underlying Basis of the Metabolic Complications of Obesity

Author(s): M. Goran, T. Alderete

The prevalence of obesity has increased throughout the last three decades due to genetic, metabolic, behavioral, and environmental factors [1]. Obesity in turn increases risk for a number of metabolic diseases including type 2 diabetes, cardiovascular disease, fatty liver disease and some forms of cancer [1]. Despite the well-known link between obesity and increased morbidity, the mechanism of this remains elusive. Thus, the question ‘why does increased body fat cause increased metabolic comorbidities’ remains unanswered. By understanding the underlying basis of obesity-associated metabolic diseases, different therapies could be designed to target relevant pathways. Although we lack a full understanding of the underlying mechanisms that result in disease, several putative explanations exist for why fat affects metabolic health. One such theory is based on the anatomic location of fat deposition and ectopic fat accumulation [2]. Specifically, current literature suggests that visceral, liver and skeletal fat accumulation affects organ function and contributes to the development of insulin resistance, fatty liver, and the metabolic syndrome [3]. However, even in individuals matched for body fat and fat distribution, significant differences can exist in metabolic outcomes, and the phenomenon of metabolically healthy obese has been well described [4]. More recent data suggest the alternative hypothesis relating excess adipose tissue to disease risk based on the metabolic function and morphological properties of adipose tissue. In this scenario, excess adipose tissue is hypothesized to contribute to a state of chronic inflammation which promotes development of insulin resistance as well as other metabolic complications by stimulating nuclear factor-κB and Jun N-terminal kinase pathways in adipocytes and the liver [5]. In this paper, we will review the hypothesis linking excess adipose tissue to increased disease risk through adipose tissue inflammation.

The Gut Microbiome and Obesity

Author(s): M. Hullar, J. Lampe

The composition of the gut microbiome is hypothesized to be an environmental factor that contributes to obesity. Results of several human studies suggest that obesity is associated with differences in the gut microbiota composition, reduced bacterial diversity, and altered representation of bacterial metabolic pathways. The obese phenotype is associated with increased microbial fermentation and energy extraction from non- digestible food components; however, until recently it was not clear how relatively small increases in energy extraction could contribute to the large and rapid weight gain observed in the animal studies. Mechanisms by which the gut microbiome may influence metabolism and energy homeostasis include regulation of energy uptake from diet, interaction with signaling molecules involved in host metabolism, modification of gut permeability, release of gut hormones, and low- grade, chronic inflammation, the latter being a hallmark of obesity- related diseases.

Starting Early: Obesity Prevention during Infancy

Author(s): L. Birch, S. Anzman-Frasca, I. Paul

Obesity prevalence among infants and young children has increased rapidly during the past 4 decades, a disturbing trend given early obesity’s association with later life obesity and its comorbidities. Fortunately, infancy is a period of great behavioral and metabolic plasticity offering numerous targets for preventive interventions. Modifiable factors that may affect early rapid weight gain and obesity risk include infant sleep duration, feeding to soothe infant distress, and the introduction of solid foods and transitional feeding. We discuss evidence linking these factors to weight outcomes, as well as results from behavioral obesity interventions in infancy, from our laboratory and others’. For example, in a recent pilot intervention, we focused on helping new mothers address three areas of infant behavior hypothesized to affect weight gain and early obesity risk: infant sleeping, crying, and feeding. First- time mothers were randomly assigned to receive either a Soothe/Sleep intervention, an Introduction of Solids intervention, both interventions, or no interventions. The interventions were delivered via home visits and showed positive effects on infant behaviors and weight outcomes at 1 year. Based on evidence from such pilot interventions, we assess the plausibility of targeting behavioral factors in infancy and suggest next steps for early prevention research.

The Economics of Food Choice Behavior: Why Poverty and Obesity Are Linked

Author(s): A. Drewnowski

Obesity in the United States does not affect all segments of the population equally. It is more prevalent in deprived neighborhoods and among groups with lower education and incomes. Inequitable access to healthy foods is one mechanism by which socioeconomic factors can influence food choice behaviors, overall diet quality, and bodyweight. Having a supermarket in the immediate neighborhood has been linked to better diets and to lower obesity rates. However, the affordability of healthy foods may have more of an impact on food patterns than does distance to the nearest store. Grains, added sugars, and added fats are inexpensive, good- tasting, and convenient. Their consumption has been linked to lower quality diets, lower diet costs, and lower socioeconomic status. By contrast, the recommended healthier diets not only cost more but were consumed by more affluent groups. New techniques of spatial analysis are a promising approach to mapping obesity rates and linking them with measures of socioeconomic status based on diverse social and economic aspects of the built environment. Low residential property values predicted bodyweights of women better than did either education or incomes. Shopping in low- cost supermarkets was another powerful predictor of bodyweight. Bodyweight gain may be best predicted not by any one nutrient, food or beverage but by low diet cost. Higher obesity rates in poor neighborhoods may be the toxic consequence of economic insecurity. Alleviating poverty may be the best, if not the only, way to stop the obesity epidemic.

The Importance of the Food and Physical Activity Environments

Author(s): J. Oppert

There is increasing interest in identifying characteristics of neighborhood environments (physical, social, economical) that might favor unhealthy dietary and physical activity patterns leading to excess weight at population level. Measurement of characteristics of the physical environment in relation to food and physical activity has greatly improved in recent years. Methods based on assessment of perceptions by residents of their neighborhood or on objective assessment of the actual built environment (such as provided by Geographic Information Systems tools) would benefit to be combined. A number of recent systematic reviews have updated our knowledge on relationships of food and physical activity environments with relevant behaviors and obesity. Available evidence appears to show more consistent evidence of association between built environment characteristics related to physical activity (‘walkability’ indices, land use mix, variety of transports. . .) with physical activity behavior than with weight status. In contrast, built environment characteristics related to food habits (accessibility to different types of food outlets, availability of healthy foods. . .) would be more consistently associated with weight status than with eating behavior. The need for data from different countries and cultures is emphasized, as much as the importance of transdisciplinary research efforts for translation of these findings into our living environment.

The Importance of Systems Thinking to Address Obesity

Author(s): D. Finegood

Obesity is clearly a complex problem for both the individual and for society. Complex or ‘wicked’ problems have common characteristics such as heterogeneity, nonlinearity, interdependence, and self- organization. As such they require solutions appropriate for complex problems, rather than a reductionist search for the causes. ‘Systems thinking’ provides new ways to consider how to collectively address complex societal problems like obesity, where biology interacts with social, cultural and built environmental factors in infinite permutations and combinations. The systems that give rise to the obesity epidemic function at multiple levels, and there are important interactions between these levels. At any given level, individual actors and organizations matter and system function is optimized when individual and organizational capacity to respond is well matched to the complexity of individual tasks. Providing system supports to help networks of individuals become ‘communities of practice’ and ‘systems of influence’ may also help to accelerate the pace of effective action against obesity. Research efforts need to move away from the relentless search for the specific isolated causes of obesity and focus on solutions that have been shown to work in addressing other ‘wicked’ problems.

Summary Discussion on Obesity Treatment: Challenges and Opportunities