Obesity is a chronic disease resulting from an imbalance in calorie intake and energy expenditure, having a complex etiology arising from genetic, biological, psychological, sociocultural and environmental factors affecting both sides of the energy balance equation.

Substantial research has shown that appetite regulation is an effective way to reduce calorific intake, and, on a long-term basis, modest reductions in food intake can lead to significant weight loss.

The gastrointestinal tract is the largest endocrine gland in the human body, secreting hormones that affect digestion, appetite and energy expenditure. Manipulation of the gut hormones, or peptides derived from them, therefore has considerable therapeutic potential.

The numerous gut hormones include oxyntomodulin, PYY3-36, CCK and glucagon-like peptide 1 (GLP-1), all of which act as short-term satiety signals following food ingestion. Associated neural signals, conveyed by the vagus and sympathetic nerves to the brain stem, work together with the hormonal signals to govern short-term satiety via the brain’s hypothalamus.

Research conducted primarily at Imperial College London has shown the gut hormones oxyntomodulin and PYY3-36 to have potent activity in reducing food intake and has thus established their potential as therapeutic mechanisms for the treatment of obesity.