SetPoint Theory and Low-Carb Diets

SetPoint Theory and Low-Carb Diets
By Heather Hamilton, PhD., LMHC, NCC, DCC  |  ©2022BreakThrough!

Set Point Theory & Body Weight

The set point theory of body weight and management suggests that our body weight is regulated around an ideal level and that hormonal and neural signals (to eat) are activated when our fat stores fall below a certain level [1].  Weight gain that may lead to obesity is caused by an imbalance (excess) of calorie intake and actual energy expenditure [2]. Calories (a measure of energy) predominantly come from fat, carbohydrates, and protein. Put simply, when we consume more food (energy) than our body uses; we gain weight. To successfully maintain our desired weight, we adjust our caloric intake to match our anticipated activity level (energy expenditure) in a given day. If we want to lose weight, then it stands to reason that we likely have to reduce our caloric intake.

Current research has shifted away from set point to the theory of allostasis. Allostasis suggests that we can positively or negatively shift our set point. If this shift is positive and steady (reduction in carbs and/or caloric intake) our brain readjusts to a new body mass index (BMI; percentage of body fat) over time. Consistent eating behavior is key to allowing our brain to readjust and re-regulate appetite to lowering BMI levels.

Low-Carb Ketogenic Diets

Many popular diets limit the consumption of carbohydrates and these are generally referred to as Ketogenic Diets (KD). These diets can be difficult to embrace both short and long-term, however, research indicates that with adherence, they produce consistent weight loss. So why do we groan and fuss at the idea of low or no-carb diets? In part, it’s because the first few days of KD are rarely fun! We may get headaches, feel depressed, and be impaired; physically and mentally. This response is not surprising considering that the brain and central nervous system (CNS) rely on the availability of glucose for energy and (feel-good) mood regulation.  This comes back to our discussions of the brain and BRIAN (Chapter 2). Humorously, BRIAN is addicted to glucose – he doesn’t like to function without a steady supply and WE are his supplier

The good news is that after 3–4 days without carbohydrate intake (KD or fasting) the CNS will find and use alternative energy sources [2]. As a result of fasting or KD, the liver eventually produces ketone bodies that can be used in place of glucose for energy (Paoli, 2014). It takes time for our brain to adjust to KD and for us to feel “normal”. What is encouraging is that once we adjust, not only are ketone bodies more efficient energy sources but our Ghrelin levels increase and we experience a reduction in appetite [3].

The problem with KD and most other diets are that dieting activates compensatory brain responses that increase the reward, perception, and preoccupation with food which in turn makes us want to eat more [1].  If we’re unaware of what is happening in our brain and body, any weight loss due to dieting (without medical or pharmacological intervention) may be short-lived.

      We hope you have enjoyed this article from The BreakThrough! Program.

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References & Related Topics

1. Behary, P., & Miras, A. D. (2014). Brain responses to food and weight loss. Experimental Physiology, 99(9), 1121-1127. doi:10.1113/expphysiol.2014.078303

2. Paoli, A., Bosco, G., Camporesi, E., and Mangar, D. (2015). Ketosis, ketogenic diet and food intake control: a complex relationship. Front. Psychol. 6:27. doi: 10.3389/fpsyg.2015.00027

3. Werthmann, J., Roefs, A., Nederkoorn, C., Mogg, K., Bradley, B. P., & Jansen, A. (2011). Can(not) take my eyes off it: Attention bias for food in overweight participants. Health Psychology, 30(5), 561-569. doi:10.1037/a0024291

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