Nerotenze testo What’s more, several studies in patients with cancer or renal disease have reported increased appetite or calorie intake in those given fish oil, compared to others given a placebo (14, 15, 16). Interestingly, one study observed that fish oil omega-3s increased the levels of a fullness hormone in obese people, but decreased levels of the same hormone in non-obese people (17). Thus, it is possible that effects vary depending on your health status and diet. However, more studies are needed before strong conclusions can be made. SUMMARY: Fish oil may be most effective at reducing hunger and appetite in healthy people following a weight loss diet. However, more studies are needed. Fish Oil May Increase Metabolism Another way fish oil omega-3s may help you lose weight is by increasing your metabolism.