Do people become obese because they overeat, or do they overeat because they are obese? The body has a system in place to maintain energy balance, just as there is a system to keep the body temperature stable. When we are hot, sweat glands release more sweat, removing heat energy through evaporation. When we are cold, our muscles contract, and we shiver creating heat. Our brain will tell us to put on a sweater.
Similarly, the body has a complex system of energy balance. When we eat, our bodies take in energy from calories. This energy is then used to power our cells and carry out all the various functions that keep us alive. When we consume more energy (food) than we need, our bodies store the excess as fat. Ideally, if this system is functioning correctly, and we happen to overeat, the body should compensate by signaling satiety or decreasing appetite so that we eat less at subsequent meals. However, when this system is not working correctly, there are no constraints, and we continue to overeat, leading to extra food consumption. Consequently, the extra energy is stored as fat, leading to weight gain.
The role of the brain in obesity
The brain plays a big part in why you end up overeating. The American Medical Association recognized obesity in June 2013 as “a disease state with multiple pathophysiological aspects requiring a range of interventions to advance obesity treatment and prevention”1. While there are many contributing factors to obesity, more and more research shows how the brain is involved. The brain is a complex organ that constantly makes decisions based on input from the body and the environment. When it comes to food, our brains consider energy levels, nutrient intake, and all those yummy hedonic clues like taste, satisfaction, and comfort eating. It’s a tricky situation. The cognitive executive section of our brain tells us what, when and how much we should eat. But when the homeostatic and hedonic cues don’t match up, it can lead to issues like obesity. Stay vigilant about your eating habits.
Pathophysiology of Obesity
Obesity is a complex condition, and scientists are still working to understand all its causes. However, one of the leading theories is related to inflammation in the hypothalamus. Other possible causes include leptin deficiency, insulin resistance, and genetic factors. Diets high in fat and calories can lead to persistent, low-grade inflammation that disrupts the signals from the hypothalamus telling you you’re full. Leptin resistance is yet another possible cause! When we have obesity, our bodies become resistant to leptin. So even when we have ample energy stored up, our brains don’t get the message, leading to overeating and, ultimately, weight gain. Leptin resistance could be caused by inflammation or genetic mutations that impair hormone signaling and its ability to suppress appetite. This brings us to the involvement of genes in the development of obesity. Research has identified specific genes linked to obesity within the central nervous system.
Conclusion
Obesity is often thought of as simply an issue with overeating, but there’s more to the story. There is more to our eating habits than just calorie consumption. In reality, we deal with complex interactions between hormones, genetics, and the brain. Through their complex interplay, they can control our appetite, regulate hunger and cravings, and maintain energy balance. If this is thrown out of balance, we can easily find ourselves struggling with overeating and obesity. It is encouraging to know that obesity is not just a challenge of willpower or overindulgence- physiological changes in our bodies also play into it. But don’t worry! We can still control our behaviors! We can make healthier food choices by being mindful of all the things influencing why, what, and how much we eat.
References
- Pollack A. AMA Recognizes Obesity as a Disease. NYTimescom. 2013 Available at: http://nyti.ms/1Guko03
- Jais A, Brüning JC. Hypothalamic inflammation in obesity and metabolic disease. J Clin Invest. 2017;127(1):24-32. doi:10.1172/JCI88878
- Gruzdeva O, Borodkina D, Uchasova E, Dyleva Y, Barbarash O. Leptin resistance: underlying mechanisms and diagnosis. Diabetes Metab Syndr Obes. 2019;12:191-198. Published 2019 Jan 25. doi:10.2147/DMSO.S182406
- Thaker VV. Genetic and epigenetic causes of obesity. Adolesc Med State Art Rev. 2017;28(2):379-405.
