The gravitostat theory: More data needed

Ohlsson, Claes; Jansson, John‐Olov

doi:10.1016/j.eclinm.2020.100530

Cited by 3 publications

(2 citation statements)

References 4 publications

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“…Similarly it has been proposed that plasma amino acid concentrations exert negative feedback on short-term EI (aminostasis) [ 15 ] or that this function occurs over longer periods owing to negative feedback from fat-free mass (protein-stats [ 16 ]), or a metabolic and motivational drive to eat to achieve a ‘target-protein intake', presumably related to requirements (protein leverage) [ 17 ]. It has also been proposed that body weight itself is more-or-less regulated (gravistat, [ 18 ], ponderostat, [ 19 , 20 ]), around set or settling points [ 21 ]. There have also been models to explain how specific nutrients may trigger overconsumption (energetic hyperphagia) and obesity development such as the current CHO-insulin model [ 22 ], itself preceded by Geiselman and Novin's sugar-induced [ 23 ] or Sclafani's CHO-induced hyperphagia models [ 24 , 25 ].…”

Section: The Role Of Energy Intake In Human Energy Balance Regulationmentioning

confidence: 99%

Diet composition and energy intake in humans

James Stubbs,

Horgan,

Robinson

et al. 2023

Phil. Trans. R. Soc. B

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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)’.

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Section: The Role Of Energy Intake In Human Energy Balance Regulationmentioning

confidence: 99%

Diet composition and energy intake in humans

James Stubbs,

Horgan,

Robinson

et al. 2023

Phil. Trans. R. Soc. B

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“…It is important to recognize that the causal relationships among variables related to energy homeostasis and the mechanisms through which they are regulated remain unclear (see [12] for discussion). Body weight per se seems an unlikely candidate for regulation, although some evidence suggests that there is a gravitostat [13]. Before the obesity epidemic, adult Americans maintained a body-mass index (BMI) that was roughly normally distributed with mean 25 kg m −2 [14], consistent with the operation of an active regulatory system.…”

Section: Introductionmentioning

confidence: 99%

Energy homeostasis from Lavoisier to control theory

Geary

2023

Phil. Trans. R. Soc. B

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The intellectual history of energy homeostasis, focusing on food intake and energy storage, is briefly reviewed. Physiological energetics was founded by Lavoisier, who in the late eighteenth century invented direct and indirect calorimetry and discovered the role of oxygen in combustion and respiration. Energy was understood well enough by the mid-nineteenth century to realize the physiological energy-balance equation, that energy intake – energy expenditure = energy storage, but this did not greatly influence physiological research for another century. Homeostasis, the concept that many vital physiological variables are actively regulated in narrow envelopes, was developed by Bernard and Cannon between approximately 1870–1940 and remains a central principle of physiology. Kennedy coined the term lipostasis in 1953 to refer to the constancy of fat mass, which Mayer argued was the mechanism regulating body weight. A parameterized control-theory model suggests that a proportional negative-feedback control system incompletely compensates weight loss during persistent negative energy balance, suggesting that Cannon's idea of constancy within a narrow envelope may not fit body-weight regulation well. This modelling encourages further application of control theory to issues in energy homeostasis, including to the development of obesity. It also sets the stage for understanding the underlying neuroendocrine mechanisms. This article is part of a discussion meeting issue ‘Causes of obesity: theories, conjectures and evidence (Part I)’.

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