Appetite responses to high-fat meals or diets of varying fatty acid composition: a comprehensive review
Dietary fatty acids (FA) act as signaling molecules with diverse effects on physiologic function. The aim of this article is to review and summarize the clinical human studies in the literature on how dietary FA composition in meals and diets affects hunger and satiety signaling in the body. Studies examining FA saturation (monounsaturated (MUFA), saturated or polyunsaturated (PUFA) FAs) or FA chain length from high-fat meals/diets were included. Measures of appetite included visual analog scale (VAS) questionnaires, appetite hormones (Cholecystokinin (CCK), glucagon-like peptide-1 (GLP-1), peptide YY (PYY), gastric insulinotropic polypeptide gastric inhibitory peptide (GIP), ghrelin, leptin, insulin) and/or energy intake (EI) data. VAS measures in 9 out of 13 studies were not influenced by FA saturation. PUFAs, followed by MUFAs, tended to induce the greatest stimulatory effect on GLP-1, GIP and PYY, which was found in 6 out of 11 studies measuring appetite-related hormones. Regarding FA chain length, five of six studies show either no difference or less hunger (VAS) and greater satiety hormone levels (two of six studies) for FAs with longer chain lengths. EI does not seem to be affected by the saturation of FAs while EI was inconclusive for studies comparing FA chain length. Possibly due to the inconsistencies in study design, little agreement is observed between the studies on the impact of FA composition on hormonal and subjective measures of appetite as well as EI. Therefore, more research on the long-term impact of dietary FA composition on appetite control may provide clearer outcomes.