This invention relates to use of a fatty acid composition comprising at least one of (all-Z omega-3)-5,8,11,14,17-eicosapentaenoic acid (EPA) and (all-Z omega-3)-4,7,10,13,16,19-docosahexaenoic acid (DHA) for the manufacture of a food stuff or food supplement for controlling and supporting body weight reduction and for prevention of body weight gain. Moreover, the present invention also relates to use of the fatty acid composition above for manufacture of a medicinal product for preventing body weight gain and for treatment and/or prevention of obesity or an overweight condition. Additionally, the present invention also includes a medicinal product containing a fatty acid composition comprising at least one of (all-Z omega-3)-5,8,11,14,17-eicosapentaenoic acid (EPA) and (all-Z omega-3)-4,7,10,13,16,19-docosahexaenoic acid (DHA) for use in controlling body weight reduction, for preventing body weight gain and for treatment and/or prevention of obesity or an overweight condition.
