Meat fills the gap

UK and Australian scientists believe they have identified how the hunger fighting hormone, peptide YY, (PYY) can be increased by eating a protein-rich diet, including meat and fish.

Although scientists have known that high-protein meals help make people feel more full and reduce appetite, the mechanism for this has until now been unclear.

Published in the journal Cell Metabolism, the researchers outline how PYY has previously been found to reduce food intake by a third in both normal weight and obese people when given by injection. "We've now found that increasing the protein content of the diet augments the body's own PYY, helping to reduce hunger and aid weight loss," said lead researcher Rachel Batterham of University College London, who is a medical research council clinician scientist.

Studies were carried out in normal weight and obese people which found that enhanced protein meals stimulated greater release of PYY than either high-fat or high-carbohydrate meals and resulted in less hunger.

The findings were supported by investigations using mice. Genetically modified mice unable to produce PYY ate more and became noticeably obese. When they were treated with PYY, the mice lost weight. "The findings show that PYY deficiency can cause obesity and that PYY appears to mediate the beneficial effects of increased-protein content diets," Dr Batterham said.

"One potential weight loss strategy is therefore to increase the satiating power of the diet and promote weight loss through the addition of dietary protein - harnessing our own satiety system." However she added that large, long-term clinical trials were necessary before any particular diet could be recommended.