The anatomy of appetite: annotated image

What factors influence what we eat?

Diagram of a person showing the various influences upon appetite

A. Limbic system: Responsible for memory and emotions. Processes information about previous experiences with food and reward. Could encourage someone to eat more or less.
B. Hypothalamus: Processes signals from gut hormones and fat, and sends its own signals. These include agouti-related protein, MCH and NPY, which block pain signals, give a calming effect and stimulate feeding. There are also other signals, such as MSH, which suppress appetite. The balance of all of these will determine a person’s appetite.
C. Vagal afferents nerve: Sends messages from the gut to the brain stem.
D. Your genes: Can affect how any of these hormones work – a variation could alter a person’s appetite to eat more or less.
E. Stomach: Secretes hormones like ghrelin, which tells you that you are hungry.
F. Pancreas: Secretes several hormones, including insulin, incretins and amylin, which tell you to eat less.
G. Duodenum: Part of the intestines that produces GLP1 and CCK, which send signals that tell you to eat less.
H. Intestines: Secrete a hormone called PYY 3-36, which tells the hypothalamus to suppress appetite.
I. Fat tissue: Secretes leptin, a powerful hormone that acts on the hypothalamus and is responsible for long-term inhibition of food intake.
J. Environmental factors: Increased marketing and availability of food, particularly high-calorie, processed foods.


‘Big Picture: Food and Diet’ (2011)

Further reading

About this resource

This resource was first published in ‘Food and Diet’ in June 2011 and reviewed and updated in August 2016.

Genetics and genomics, Neuroscience, Ecology and environment, Physiology, Psychology, Health, infection and disease
Food and Diet
Education levels:
16–19, Continuing professional development