Does Omega 3 Fish Oil Help With Weight loss? Research Reveals Answers


Obesity is a rising epidemic and is in many ways a major health hazard. Bulging waistlines and increasing belly fats are not only ungainly to look at, but is a also a fair predictor of poor health[1][2] and an indicator of internal fat surrounding the organs.

Research has proven that lower levels of  omega 3 indicate poor scores of BMI(body mass index) which suggests omega 3 supplementation could promote favorable fat mass and overall weight. [3][4][5]

Fish Oil & Fat loss Study

Clinical Proof 1

Couet and team’s research study of 1997 demonstrated how fish oil supplementation reduced fat mass in the study participants. There were 6 normal weight, young adults (average age 23 years) in this trial. They were eating a fixed diet which gave them the same amount of calories each day.

This diet gave them 6 gram of visible fat every day. Visible fat is the fat (oil, butter, cheese, lard etc.) which we use for cooking or garnishing and that which is basically visible to us. This does not include the fats present inherently within foods.

For the first 3 weeks of the research study, they were given other oil in the diet but during the next three weeks, this oil was replaced by fish oil, while keeping the amount of fat and therefore the calories, constant.

The body fat mass was measured at the beginning of the trial, then after first three weeks and then lastly, at the end of the next three weeks.

The study participants lost a lot of fat mass after their regular oil was substituted with fish oil. The average reduction in fat mass of these people was 0.3 kg when they were eating regular oil but it fell further to 0.9 kg when they switched to fish oil (ref: Graph).

Clinical Proof 2

In 2010 Noreen and his fellow researchers evaluated the effect of giving fish oil to healthy adults and measuring the change in their lean mass and fat mass after supplementation. In this double blind, placebo controlled trial, the researchers enrolled 44 men and women.

These 44 trial participants were randomly put into either of the two treatment groups. Group 1 got 4 gram fish oil every day for 6 weeks. This gave them 1600 mg/day EPA (Eicosapentanoic acid) and 800 mg/day DHA (Docosahexanoic acid). Group 2 was the placebo group. This group was given 4 gram safflower oil per day for 6 weeks.

The researchers then calculated how much change there was in the fat mass, lean mass and fat percentage of each trial participant after these 6 weeks of supplementation.

As can be seen from the graph, the fish oil group had an increase in fat free mass while their fat mass reduced. By comparison, the placebo group did not do well. While those who took fish oil were able to reduce their fat content by 0.4%, placebo group saw a 0.3% increase in the fat content of their body.

Fish oil does help in reducing fat but the effects are more pronounced when coupled with exercise.

Clinical Proof 3

A study performed by Warner and team in 1989 has shown that fish oil alone is unable to influence fat mass and it was only when it was given to regular exercisers that it helped.

This trial involved 34 people who were randomly put into 4 groups. Group 1 took fish oil and exercised, Group 2 took fish oil, Group 3 took corn oil and Group 4 took nothing

Out of all these four groups, the fat mass decreased noticeably only in Group 1 i.e. those who took fish oils and exercised too. There was no effect in group 2 who only took fish oil (did not exercise) which means that the fat loss was due to exercise or combined effect of fish oil and exercise.

To conclude, fish oil does help in reducing fat but the effects are more pronounced when coupled with exercise. So, people aiming for weight loss need to combine fish oil intake with exercise to get the best results.

Fish Oil & Weight loss Study

Maintaining a good weight is the key to good health. Weight loss requires long-term and consistent approach which includes a balanced combination of healthy diet habits and physical exercise.Though it is believed by many that regularly consuming fish oil or omega-3 fatty acids helps in losing weight, scientific trials conducted so far have not uniformly proved this conclusively.

While some scientific trials have shown that fish oil or omega 3 fatty acids augment the weight loss effect of calorie restriction, others say that there is only minor influence of fish oil on weight loss.

Weight loss is more than fat loss – it is a combination of muscle loss plus fat loss plus water loss.

Clinical Proof 1

The research trial done by Kunesgova and team in 2006 is one such trial which showed weight loss effect of omega 3 fatty acids over and above that achieved by caloric restriction.

Twenty obese women volunteered to be a part of this randomized, placebo controlled trial. All these women were following a very low calorie diet. They were randomly put into either of two groups. Women in Group 1 were given omega 3 fatty acids while those in the second group received placebo for 3 weeks.

Body weight, BMI and hip circumference of each study participant was noted before starting the trial. These parameters were measured once again after the 3 week supplementation to see how much they had improved.

As shown in the graphs, average weight loss, BMI reduction and decrease in hip circumference was higher in fish oil group compared to placebo.

Clinical Proof 2

A trial done by Munro and Garg in 2012 failed to show any weight loss effect of taking omega-3 fatty acid (the active ingredient of fish oil which makes it healthy). Two groups were made at random in this double blind trial.

Group 1 had 18 participants who took 6 capsules of fish oil every day for 4 weeks. Each fish oil capsule contained 70 mg EPA (Eicosapentanoic acid) and 270 mg DHA (Docosahexanoic acid). Group 2 had 14 participants who took placebo capsules daily for 14 weeks.

All these people were eating a very low calorie diet for the first 4 weeks after which they switched to a maintenance diet (a low calorie diet designed to sustain weight loss).

Both groups lost almost same amount of weight after the first 4 weeks as well as at the end of the 14 week supplementation period (ref: Graph).

By the end of the first 4 weeks, there was an average weight loss of 6.87 kg among people who took fish oil capsules which was just a little more than weight loss in placebo group (6.54 kg). Even during the next 10 weeks, both groups lost about same weight, 1.69 kg in fish oil group and 1.57 kg in placebo group. Although fish oil group lost more weight in this study, it is too small a difference to be deemed statistically relevant.


  1. Lee, C.M., et al., Indices of abdominal obesity are better discriminators of cardiovascular risk factors than BMI: a meta-analysis. J Clin Epidemiol, 2008. 61(7): p. 646-53
  2. Coutinho, T., et al., Central obesity and survival in subjects with coronary artery disease: a systematic review of the literature and collaborative analysis with individual subject data. J Am Coll Cardiol, 2011. 57(19): p. 1877-86.
  3. Micallef, M., et al., Plasma n-3 Polyunsaturated Fatty Acids are negatively associated with obesity. Br J Nutr, 2009. 102(9): p. 1370-4.
  4. Saito, E., et al., Docosahexaenoic acid content in plasma phospholipids and desaturase indices in obese children. J Atheroscler Thromb, 2011. 18(4): p. 345-50.
  5. Burrows, T., C.E. Collins, and M.L. Garg, Omega-3 index, obesity and insulin resistance in children. Int J Pediatr Obes, 2011. 6(2-2): p. e532-9.