Models of body weight and fatness regulation

Abstract

Body weight and fatness appear to be regulated phenomena. Several different theoretical models are available to capture the essence of this idea. These include the set-point, dynamic equilibrium, adiposity force, control theory-settling point, Hall–Guo, operation point and dual intervention point (DIP) models. The set-point model posits a single reference point around which levels of fat are regulated. The dynamic equilibrium model suggests that the apparent regulation of body fat around a reference point is an illusion owing to the necessary impacts of weight change on energy expenditure. Control theory focuses on the importance of feedback gain and suggests set-point and dynamic equilibrium are ends of a continuum of feedback gain. Control theory models have also been called ‘settling point’ models. The Hall–Guo, operation point and DIP models also bring together the set-point and dynamic equilibrium ideas into a single framework. The DIP proposes a zone of indifference where dynamic equilibrium ‘regulation’ predominates, bounded by upper and lower intervention points beyond which physiological mechanisms are activated. The drifty gene hypothesis is an idea explaining where this individual variation in the upper intervention point might come from. We conclude that further experiments to test between the models are sorely required. 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

“…Indeed, voiding excess ingested energy is part of the homeostatic control of weight [ 115 ] and was apparent at a population level in a cohort of predominantly healthy, lean children demonstrating protein leverage [ 89 ]. Genetic factors play a role in increasing the susceptibility to weight gain with overfeeding, as does insulin resistance and previous obesity [ 1 , 114 ], but the mechanisms are not fully understood. Variation in genetic loci involved in protein metabolism and signalling, including FGF21, would be expected to associate with variation in obesity risk, both between individuals within a population and between populations as a function of ancestral diet [ 6 , 111 ].…”

“…It is, on the one hand, straightforwardly true that excess body fat can accumulate only if more energy is eaten than is expended. On the other hand, an immense amount of research has produced a plethora of information and theories, but there is little consensus about why such energy imbalance develops or what to do about it [ 1 ].…”

Crafting a healthier future: exploring the nexus of product design, digital innovations and dynamic marketing for obesity prevention. A literature review

“…In this sense, the WHO (2020) defines guidelines for the obesity prevention that aim to change the obesogenic environment in order to ensure a healthy lifestyle at every stage of an individual's life such as the promotion of breastfeeding or the modification of the urban environment to the promotion of physical activity. However, an innovative perspective on body weight regulation defined the "Dual Intervention Point" (DIP model) explains how the human body regulates body weight (Speakman and Hall, 2023) through two intervention points: upper and lower, representing respectively the level of body weight above and below which are activated physiological mechanisms that prevent further loss or weight increases reaching the so-called "zone of indifference" where body weight may vary without activating such mechanisms. Some individuals may have a lower upper intervention point than others, which means they are more likely to gain weight and become obese.…”