Role of gastrointestinal factors in hunger and satiety in man.

There is, we feel, a strong case to be made for a major influence of gastrointestinal factors in the control of eating behaviour in humans. Moreover, the findings suggest that satiety and hunger are controlled by different gastrointestinal mechanisms. Gastric distension is perhaps the most important factor that stops people eating, but a true feeling of satiety also requires the presence of nutrients in the small intestine. Hunger appears to be little influenced by the amount of food in the stomach and appears to be more dependent on the nutrient load in the small intestine. I do not mean by this to suggest that the gastrointestinal mechanisms are the only mechanisms controlling eating behaviour in humans or even the most important. Nevertheless they constitute an important and fundamental control system that links with the post-absorptive mechanisms and a plethora of social and conditioning factors to influence what we eat.