Eat More Fat and Get Bigger and Leaner
Many dieters and athletes make the mistake of avoiding all fats when trying to lose weight. It is generally believed that a high-fat diet is a contributing factor to excess body fat accumulation due to the greater energy density of fat and the relative inability of the body to increase fat oxidation in the presence of over consumption of fats. Over the last decade, the science of fat’s effect on dieting has changed, we now know that different fats have different biological effects on the body. For example, several rodent studies have shown clearly that diets rich in omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are found in large amounts in the oil from cold-water fish, lead to significantly lower total body fat stores versus diets rich in other fatty acids, yet how the exact mechanism for fat loss is not understood. Additionally, omega-3 fatty acids have been linked to an increase in performance.
A study published in the Journal of the International Society of Sports Nutrition reported that 30 male athletes in their mid-20s who trained an average of 17 hours a week supplemented their diet with 5 ml of seal oil containing 375 mg of EPA and 510 mg of DHA, or an olive oil placebo, for 21 days. Before and after this period, subjects were assessed with a time trial race and maximum voluntary contractions. Omega-3 supplementation increased maximal isometric contractions while decreasing the reduction of powder during Wingate test performance. Researchers have recently reported that omega-3 fatty acids also increase lean muscle mass and decreased fat mass, in addition, it can lower cortisol levels.
The study had 44 men and women participate in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of resting metabolic rate were measured in conjunction with body composition analysis. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of safflower oil; or 4 g/d of fish oil supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA).
Safflower oil (SO): 4 g/d of safflower oil administered in 4 enteric-coated capsules (each capsule provided 1 g of cold pressed, high linoleic acid, safflower oil).
Fish oil (FO): 4 g/d concentrated fish oil administered in 4 enteric-coated capsules (each capsule provided 400 mg EPA and 200 mg DHA).
Subjects took 2 capsules with breakfast and 2 capsules with dinner for a 6 week period. All testing was repeated following 6 week of supplementation.
All tests were repeated following 6 weeks of treatment. At the end of the study, compared to the safflower oil group, there was a significant increase in lean muscle mass following treatment with fish oil, a significant reduction in fat mass, and a tendency for a decrease in body fat percentage. An interesting point, the fish oil was added on top of an ad libitum diet, with instructions given to the subjects to maintain their normal dietary patterns throughout the study. So the subjects increased their fat intake and they gained more muscle and lost more fat. No significant differences were observed for body mass, RMR or respiratory exchange ratio. There was a tendency for salivary cortisol to decrease in the fish oil group. There was a significant correlation in the fish oil group between change in cortisol and change in fat free mass and fat mass. 6 weeks of supplementation with fish oil significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following fish oil treatment.
The researchers suspected that dietary fish oil increases lean muscle mass by simply decreasing the breakdown of protein tissue caused by inflammatory cytokines, and this results in an increased accretion of protein over time or through decreased cortisol. It is well established that cortisol increases protein catabolism and the reduction in cortisol from fish oil may have increased anabolic activity. In conclusion, fish oils can not only increase lean muscle mass, but also increased fatty acids may also accelerate fat loss.
Noreen EE, Sass MJ, Crowe ML, Pabon VA, Brandauer J, Averill LK. Effects of
supplemental fish oil on resting metabolic rate, body composition, and salivary
cortisol in healthy adults. J Int Soc Sports Nutr. 2010 Oct 8;7:31.