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's Weight Regulators: Hypothalamus, Mesolimbic Area, and Cognitive Lobe

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.

Hypothalamus - The Energy Accountant

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.

Mesolimbic Area - The Hedonist

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.

Cognitive Lobe - The Wise Decision-Maker

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.

References

  1. Dhillo WS, Small CJ, Stanley SA, et al. Hypothalamic interactions between neuropeptide Y, agouti-related protein, cocaine- and amphetamine-regulated transcript and alpha-melanocyte-stimulating hormone in vitro in male rats. J Neuroendocrinol. 2002;14(9):725-730.
  2. Papies E, Stroebe W, Aarts H. Pleasure in the mind: Restrained eating and spontaneous hedonic thoughts about food. J Exp Soc Psychol. 2007;43(5):810-817. doi:10.1016/j.jesp.2006.08.001
  3. Barbano MF, Cador M. Opioids for hedonic experience and dopamine to get ready for it. Psychopharmacology (Berl). 2007;191(3):497-506. doi:10.1007/s00213-006-0521-1
  4. Meye FJ, Adan RAH. Feelings about food: The ventral tegmental area in food reward and emotional eating. Trends Pharmacol Sci. 2014;35(1):31-40. doi:10.1016/j.tips.2013.11.003
  5. Bello NT, Hajnal A. Dopamine and binge eating behaviors. Pharmacol Biochem Behav. 2010;97(1):25-33.
  6. Cserjési R, Luminet O, Poncelet AS, Lénárd L. Altered executive function in obesity. Exploration of the role of affective states on cognitive abilities. Appetite. 2009;52(2):535-539.