Regulation of Food intake

 Regulation of Food intake

Since eating is a voluntary act so conscious sensation of hunger and appetite indicating whether food is needed or not, is a prerequisite for the regulation of food intake or eating. Hunger is caused by the physical need of the food whereas appetite is the emotional (psychological) desire which may or may not be associated with the need of food.

Hunger, i.e. desire for taking food, is controlled by a centre in the hypothalamus, i.e. lateral hypothalamic area. There is another centre ventromedial hypothalamic nuclei  in Ventromedial nucleus of  lateral hypothalamic area tuber cinerium called satiety centre, which inhibit the hunger centre when it is satisfied with the amount of food appropriate to calorific requirement resulting loss of desire for taking food.

When the satiety centre is not satisfied with the amount of food appropriate to calorific requirement, then this centre is not sufficiently stimulated to inhibit the centre so the hunger centre is not inhibited resulting in the desire for food. Appetite, on the other hand, is conditional and not dependent to calorific need.

The various modes of activation suggesting the regulatory activity of the appetite centre are as follows-

1. Concentration of blood glucose. Low glucose concentration stimulates the lateral hypothalamic nucleus producing increase hunger and food intake. When glucose concentration increases after intake of food, the ventromedial centre of the hypothalamus is satisfied and hunger centre is inhibited thus the person stops eating

2. Temperature variation of blood. Low temperature stimulates food intake and vice versa.

3. The proportionate amounts of active fat in fat cells also act in a regulatory manner.

4. The concentration of serum amino acids also regulates the hunger centre.

5. Other factors also play some part. The hypothalamic hunger centre receives projection from the cortex, so it is under voluntary control. Emotional stress, such as worry, tension, etc. also plays a major part. Sight, smell and thought of food also stimulate the hunger.

6. The satiation achieved by food intake and its regulatory role are partly dependent also on the digestive tract. The feeling of fullness after a heavy meal may depend on the distention of the stomach, which may be brought about by proprioception. Nervous projections may also play a part.