The objective of this study was to investigate the impact of hyperphagia of three types of dietary fat on body weight gain and omega-3 fatty acid status of adipose tissue.

Male Wistar rats (302 ± 4 g; n = 42) were over a four week period fed diets that differed in their fatty acid composition. One group was fed diet suppplemented with saturated fat (T-diet;), another with sunflower oil (S-diet), and the third with cod liver oil (CLO-diet). The diets were similar in their total dietary energy from fat (7.5 energy%). Hyperphagia was induced by chronic ICV infusion for 14 days of melanocortin receptor antagonist (HS024), control rats received artificial cerebrospinal fluid. Food intake and body weight were monitored, and at the end of the study the fatty acid composition was analyzed in lipids of blood plasma, skeletal muscle and adipose tissue.

No difference was found in the cumulative energy intake or body weight gain between the hyperphagic dietary groups. The proportion of omega-3 polyunsaturated fatty acids in adipose tissue of hyperphagic rats fed CLO-diet was maintained compared with their controls, while it decreased in rats fed S-diet or T-diet.

The study demonstrates that body weight gain due to hyperphagia is unaffected by the type of dietary fat. Hyperphagia of diet containing marine omega-3 fatty acids improves fatty acid status, which is indicated to be associated with lower risk of overweight-related diseases.