The Role Of The Brain In Weight Gain And Weight Loss

The Role Of The Brain In Weight Gain And Weight Loss

Managing optimal weight is an integral part Of maintaining a healthy lifestyle. This is because being overweight and obese are risk factors for several serious illnesses such as diabetes, high blood pressure, high cholesterol, heart attacks, brain strokes, cancer, etc. Obese and overweight people, therefore need to lose weight in order to reduce the risk of acquiring these serious and disabling diseases.

Weight loss involves a good diet regimen coupled with regular exercises. And the brain Plays an important role in helping an individual to stick to both of these activities. This is because there are mechanisms by the brain regulates diet control and eating.

Role Of The Hypothalamus

The hypothalamus is an endocrine gland located in the brain and which is deeply involved in controlling eating behaviour. It has ‘hunger’ and ‘satiety’ centres, Which make us eat food when hungry and makes us stop when full. These are mediated through a variety of chemicals/hormones


Leptin. also known as “hormone of energy expenditure. is predominantly made by adipose (fat) cells. It regulates energy balance by inhibiting hunger. Less hunger leads to less food consumption, leading to weight loss Leptin exerts its effects by acting on the hypothalamus (arcuate nucleus). Obese have ‘leptin resistance.. which means that hunger is not inhibited, the presence of high levels of leptin. resulting in overeating. This is similar to ‘insulin resistance’ in diabetic patients.


Ghrelinis also called the ‘hunger hormone. ‘ Ghrelin acts on the hypothalamus to stimulate hunger Thus, the action of ghrelin is exactly opposite to that of leptin. After eating food, ghrelin levels decline to the lowest levels. It rises again, just before the time of the next to stimulate hunger.

The hypothalamus has ‘hunger’ and ‘satiety’ centres which make us eat food when hungry and makes us stop when full

So it is the balance between the levels of leptin and ghrelin that regulate eating behaviour. Cholecystokinin (CCK – made in the upper small bowel) and glucagon-like peptide-I (GLP-I – made in the small bowel) are released when the food enters the small bowel. These hormones make us feel full and we stop eating. CCK, if injected in a mouse’s brain, stops it from eating.

Pleasure Centres In The Brain And Eating Behaviour

While food is essential for survival, it is the pleasure associated With food that makes eating worthwhile. When we are happy. we eat more! The reverse is also true. When one has eaten to his/her heart’s desire. there is happiness and satisfaction. Almost every celebration or party involves a good spread of vanous food ‘terns Besides. most people tend to overeat in a party or during a celebration.

The happiness associated with eating food is because food stimulates the same reward system of the brain that gets stimulated by other pleasurable activities such as sex, games or watching a movie. The area involved in a ‘reward feeling’ is the mesolimbic cortex of the brain and the effects are mediated by a neurotransmitter, dopamine.

All food types stimulate reward centres of the brain. However, the effects are more pronounced with sweet items or high-calorie foods such as cakes, aerated soft drinks, sweets, etc This explains why some people crave for sweets/cakes. The pleasurable sensation associated with eating desserts could force a person to have them, even though full.

Over a period of time, eating can become an ‘addiction’ too, similar to alcohol or smoking addiction. A ‘food-addicted’ person eats merely to experience the pleasurable sensations associated with eating, rather than to satisfy hunger. This behaviour can result in overweight and obesity. Counselling and psychiatry consultation can help in these situations.

Role Of Special Senses In Eating Behaviour

When it comes to the choice and liking of food, many factors play a role. These include the look. smell and taste of food.

  • An aroma of good food can be experienced from a distance. which increases the appetite and desire to eat.
  • A dish well served and nicely arranged is also very appealing
  • The taste of food is vital, as it increases appetite.

Hence the sensations – smell. sight and taste of food are recognized and appreciated in special brain centres. Hence, disorders or damage of neurons in these special brain areas. may affect eating behaviour of an individual.

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