How Much Fish Oil for Weight Loss?

Fish oil has had positive effects on many different health outcomes, including triglyceride levels and heart disease risk. Due to these positive findings, fish oil’s effects on weight loss and body composition have also been examined in several animal and human studies.


Studies examining fish oil’s effects on weight loss show mixed results. A study, published in "American Journal of Clinical Nutrition" in 1999, reports that fish oil is possibly effective for weight loss and some studies show eating fish accelerates weight loss in overweight individuals. MedlinePlus reports that taking 6 g of fish oil supplements containing 260 mg of docosahexaenoic acid, or DHA, and 60 mg of eicosapentaenoic acid, or EPA -- the two types of omega-3 fatty acids in fish oil -- may help decrease body fat in people who exercise.


A 2010 study published in the “American Journal of Clinical Nutrition” found that overweight and obese subjects who took 15 g of EPA plus DHA per day lost weight, however the amount of weight lost was not significantly more than overweight and obese subjects who took placebo capsules. A 2007 study also published in the “American Journal of Clinical Nutrition” found that overweight subjects who consumed 6 g of tuna fish oil supplements per day had lower triglyceride levels, increased HDL, or good cholesterol levels, and reduced body fat.


MedilinePlus reports that taking 7.5 g of fish oil per day may be effective to help slow weight loss related to cancer in some patients. However, according to the American Cancer Society, there are too few studies that show favorable results for fish oil’s effects on cancer-related weight loss and not enough information exists to determine if omega-3s in fish oil do indeed help reduce cancer-related weight loss.


Although fish oil may not necessarily help accelerate weight loss, it does contain omega-3 fatty acids DHA and EPA, which are essential fats the human body requires on a daily basis. According to the American Pregnancy Association, adults require at least 220 mg of EPA and 220 mg of DHA per day and pregnant and nursing women require at least 300 mg of DHA each day. The Institute of Medicine Food and Nutrition Board established adequate intake levels for omega-3 fatty acids for adults as 1.1 g to 1.6 g per day, depending on gender and age.


Consult your doctor before you take fish oil, and before you begin a new weight loss program. The omega-3 fatty acids in fish oil can reduce inflammation to the point that they suppress your immune system, and they can also increase your risk of excess bleeding. Fish oil might also interact with some medications, such as blood thinning medications, such as aspirin and coumadin, and cause adverse effects.