Is CLA a Safe Natural Weight Loss Aid?

Conjugated Linoleic Acid (CLA) is a naturally occurring fat found in certain animal products such as beef, lamb, and dairy. The findings of a recent study of 80 overweight and obese people in China showed that 1.7 grams twice daily of CLA for twelve weeks reduced body fat by 2% and body weight by 0.9% (Chen et al, Nutrition 2012¹). In this study, total cholesterol and LDL (“bad cholesterol”) increased and HDL (“good cholesterol”) decreased, though these changes were not statistically significant. Several other studies have also shown slight decreases in body fat with CLA supplementation. However, as with the Chinese study, these studies are typically conducted over a short timeframe with a small number of participants, in a free-living environment where variables such as exercise and food intake cannot be fully controlled. These studies also use a highly purified form of CLA.

CLA is a complex molecule with many different configurations, called isomers. The most common, naturally occurring CLA isomers in food are not the same as the isomers tested in Chen et al. or other studies. Rather, clinical studies use highly concentrated forms of CLA that are rarely found in food, because these are most effective in weight loss studies. Furthermore, the most commonly occurring isomers in foods and supplements are more likely to cause side effects such as nausea, vomiting, diarrhea, acid reflux, decline in blood glucose control, increased insulin resistance, and increased cholesterol and triglycerides. Supplement manufacturers are not required to disclose which CLA isomers are contained in their supplement and they can contain dangerous quantities of isomers with negative side effects, leading to an increased risk of diabetes and heart disease. Several of these potentially harmful CLA supplements are already available and promoted as weight loss aids in the US.

Considering the risks and the very small impact CLA has on weight loss, it is clear that CLA is not the new weight loss panacea. Rather, the healthiest way to lose weight without the aforementioned unhealthy side effects is to eat fewer calories and exercise regularly. Consider following the advice of the US Department of Agriculture’s My Plate initiative; increase your fruit and vegetable intake and choose lean meats, low fat dairy and whole grains. By gently shifting your daily energy balance so that you use more than you eat, you can achieve a safe 1-2lb per week weight loss and actually reduce your risk of diabetes and heart disease at the same time!

Resources:

http://www.choosemyplate.gov/healthy-eating-tips/ten-tips.html

http://www.fruitsandveggiesmorematters.org/

http://www.cooperaerobics.com/Health-Tools/Recipes.aspx

References

1. Chen SC, Lin YH, Huang HP, Hsu WL, Houng JY, Huang CK. Effect of conjugated linoleic acid supplementation on weight loss and body fat composition in a Chinese population. Nutrition, 2012 January 18^th (epub)