To evaluate the association between fatty acid (α-linolenic acid (ALA), EPA, DHA, palmitic, stearic, oleic, linoleic and arachidonic acids) intake and prospective weight change in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition.

Prospective cohort study with mean follow-up time of 6·5 years. In a total of 9182 men and 10867 women aged 35 to 64 years, from body weight measurement at recruitment and calibrated body weight during follow-up, weight change was expressed as mean annual weight change relative to baseline weight (%/year) and categorised into four groups (weight loss, <−2·5%/5 years; stable weight, between −2·5 and +2·5%/5 years; small weight gain, ≥2·5 to <7·5%/5 years; large weight gain, ≥7·5%/5 years). Energy-adjusted dietary fatty acid intake data were estimated from the FFQ completed at baseline. Multivariate linear regression models as well as multinomial logistic regression analyses (carbohydrate replacement models) were conducted.

Stearic acid intake was linearly associated with weight gain (P < 0·01) in men and women. Linear associations also existed for ALA and arachidonic acid intake, significantly so in women. In multinomial models, women in the highest tertile of ALA and stearic acid intake showed increased OR (95 % CI) for small weight gain (1·16 (0·94, 1·88) and 1·24 (1·08, 1·43), respectively), and large weight gain (1·39 (1·03, 1·88) and 1·56 (1·27, 1·90), respectively), whereas OR were non-significantly increased in men. Dietary intake of ALA was inversely associated with large (0·80 (0·65, 0·99)) weight gain in women only.

These results suggest differential effects of single dietary fatty acids on prospective weight gain in adults.