Set Point

The “set point” theory for obesity is a concept that suggests each individual has a genetically predetermined weight range or a specific level of body fat that their body strives to maintain. It proposes that the body has mechanisms to regulate appetite, metabolism, and energy expenditure to defend this set point weight, much like how the body regulates temperature or blood pressure within a narrow range.

The set point theory surmises that the body has mechanisms (some shown above) to regulate appetite, metabolism and energy expenditure to defend the set point weight.
Adapted from Schwartz et al. Obes Rev 2010;11:531–47; 2. Sumithran et al. N Engl JMed
2011;365:1597–604

The set point theory suggests that the body has a natural and stable weight range that it strives to maintain. This range is determined by genetic and physiological factors. Within this theory, the body employs mechanisms to regulate energy balance. When body weight falls below the set point, physiological responses such as increased hunger (via changes in levels of hormones such as ghrelin and leptin) and decreased metabolic rate are activated to encourage weight gain. When weight exceeds the set point, the body increases energy expenditure and reduces appetite to promote weight loss.

The set point theory acknowledges that the set point weight varies from person to person and can be influenced by genetic and environmental factors. According to this theory, when individuals attempt to lose weight through dieting and exercise, their bodies may resist by increasing appetite and reducing metabolic rate, making it challenging to maintain weight loss in the long term.

However, the set point theory is a subject of ongoing debate in the field of obesity research. Some researchers argue that it oversimplifies the complex nature of weight regulation, while others see value in understanding how the body’s defence mechanisms may impact weight management.

The set point theory for obesity is just one of several theories aimed at explaining the regulation of body weight and the complexities involved in weight management. While the concept of a set point is useful in understanding the body’s resistance to weight loss, it is important to consider that weight regulation is influenced by a combination of genetic, environmental, and behavioural factors.

References:

- Schwartz, M. W., Woods, S. C., Porte, D., Seeley, R. J., & Baskin, D. G. (2000). Central nervous system control of food intake. Nature, 404(6778), 661-671.

- Speakman, J. R., Levitsky, D. A., Allison, D. B., Bray, M. S., de Castro, J. M., Clegg, D. J., … & Westerterp-Plantenga, M. S. (2011). Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity. Disease Models & Mechanisms, 4(6), 733-745.

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