Excess weight gain is influenced by the intricate neurobiology of appetite control. When we consume more than we burn (whether it's carbs, fat or protein), the surplus energy becomes stored fat. Our body weight is carefully regulated for survival. Even a slight long-term calorie surplus can lead to weight gain.
The brain plays a significant role in our eating habits and energy balance. It consists of three areas that control weight: the hypothalamus, the mesolimbic area, and the cognitive lobe. Each area has specific functions and connections that contribute to obesity.
The hypothalamus controls our eating behaviours. It receives signals from the gut, fat, and other organs (yes, fat is an organ!), triggering our desire to seek food when energy availability is low. It primarily regulates our appetite but not necessarily the actual consumption of food (1). It responds to information about the nutrients consumed and the energy resources available in our body.
The mesolimbic area is responsible for the emotional and pleasurable aspects of eating, known as hedonic eating. It can make us crave or enjoy food, even when we're already full (2). Signals transmitted through dopamine, opioids, and endocannabinoids play a role in these feelings (3). Research says that people who struggle with excess weight may have dysregulated signals in this area, leading to overeating (4,5). Hormonal regulation, cognitive therapy, and sometimes medications or supplements can help manage this dysregulation.
The cognitive lobe is responsible for executive functions and overriding primal behaviours driven by the mesolimbic area (6). To make wise decisions regarding food, it's essential to be well-rested and manage stress levels. Excessive eating often occurs in the evening when fatigue, stress, or boredom can affect our decision-making abilities.In summary, appetite control is a complex process involving neural circuits, signals from the gut and other organs, and executive control by higher brain centres. These networks can be altered in obesity. Understanding these mechanisms can help in managing weight and making healthier eating choices.
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