Leptin is primarily known as a hormone that is active in the hypothalamus in the brain. It plays a role in decreasing body fat mass and suppressing food intake making you feel full. But research studying activity is showing that leptin serves a much broader purpose than telling you that you’ve had enough slices of pizza.
It turns out that hypothalamus is not the only part of the brain with leptin activity, nor is food intake control leptin’s only function. Leptin also influences “… motivation, learning, memory, cognitive function, neuroprotection, reproduction, growth, metabolism, energy expenditure and more.” This means that when leptin signaling is working properly, a lot of body and brain functions are going to run smoothly as a result. On the other side of the coin is, of course, the fact that improper or impaired leptin signaling has an impact across all sorts of systems.
One of the interesting points here is that leptin has a real effect on multiple cognitive functions; once again, evidence that nutrition affects our brains! Leptin resistance is commonly associated with obesity and increasing age, which is a bit of a vicious cycle: higher body fat levels often influence leptin resistance, which in turn leads to lower fat metabolism and increased fat mass. You can see the issue. Not only does leptin resistance negatively impact the body physically, there appears to be a growing list of cognitive functions that suffer as well.
What about strategies to try and increase metabolism and return leptin signaling to normal? One tactic is a decrease in the about of simple carbohydrates and sugars in the diet (think about how often you choose soda over a glass of water). Another is increasing aerobic exercise. When there are a lot of these simple carbs and sugars in a person’s diet, they can start to ‘build up’ as stored fat instead of being ‘”burned off”. As mentioned earlier, higher body fat gain, and so on. If we can reduce the amount of simple carbs and sugars, and increase aerobic exercise, we are likely to increase carbohydrate metabolism and, by extension, reduce the amount of fat building up from carbohydrate in the diet.
Morrison, Christopher D. “Leptin Signaling in Brain: A Link between Nutrition and Cognition?”Biochimica Et Biophysica Acta (BBA) – Molecular Basis of Disease, vol. 1792, no. 5, 2009, pp. 401–408., doi:10.1016/j.bbadis.2008.12.004