Anger and hostility levels rise on a low fat diet - whereas anger, hostility, tension and anxiety decline on a high fat diet

This study was published in the British Journal of Nutrition 1998 Jan;79(1):23-30.

Study title and authors:
Alterations in mood after changing to a low-fat diet.

Wells AS, Read NW, Laugharne JD, Ahluwalia NS.

Centre for Human Nutrition, University of Sheffield, Northern General Hospital, UK. a.s.wells@sheffield.ac.uk

This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/9505799

This study examined the effects on mood of reducing dietary fat in ten male and ten female healthy volunteers aged between 20 and 37 years.

Each volunteer consumed a diet containing 41% energy as fat for 1 month. For the second month half of the subjects changed to a low-fat diet (25% energy from fat) and the remainder continued to eat the diet containing 41% energy from fat.

The study found:
(a) Anger and hostility significantly increased after 1 month in those on the low-fat diet.
(b) There was a slight decline in anger and hostility in those on the higher fat diet.
(c) Tension and anxiety declined in those consuming the higher fat diet but did not change in the group consuming the low-fat diet.
(d) There was a decline in concentrations of (the good) high density lipoprotein cholesterol (HDL-C) after the low-fat diet and a small increase in subjects consuming the higher fat diet.

To conclude: The results suggest that a change in dietary fat content from 41 to 25% energy may have adverse effects on mood.