A French study indicates that fish oil or taking omega-3 fatty acid supplements can help weight loss.  The study shows that rats fed a calorie restricted diet supplemented with n-3 long-chain  polyunsaturated fatty acids for 10 weeks lost more weight, compared to rats on diets supplemented either with 18:1 n-9 (OLE) or 18:3 n-3 (ALA) for ten weeks. No impact of the n-3 supplementation on muscle weight was observed.  Evidence also suggests that n-3 fatty acids can also improve insulin sensitivity. (David Liu, PHD)Guelzim N, Huneau JF, Mathé V, Tesseraud S, Mourot J, Simon N, Hermier D.  N-3 fatty acids improve body composition and insulin sensitivity during energy restriction in the rat.  Prostaglandins Leukot Essent Fatty Acids. 2014 Jul 26.https://www.ncbi.nlm.nih.gov/pubmed/25172359