CLA increases regain of muscle, but does not affect body weight

Conjugated linoleic acid (CLA) dose-dependently improves regain of fat-free mass (muscle) and resting metabolism following weight loss, but does not have any effect on the amount of weight regained.

A group of 26 men and 28 women, who on average were 38-years-old and had a body mass index (BMI) of 27.8, lost weight on a very-low-calorie diet (VLCD) of 800 calories per day for three weeks.

They lost an average of 12.9 pounds or 6.9 percent of body weight.

DOSE

For the next three months (13 weeks) subjects were given either a low or high dose of CLA, or a low or high dose of placebo.

They were then randomly assigned to received either:

?????—1.6 grams of CLA per day (low dose)
?????—3.2 grams of CLA per day (high dose)
?????—1.6 grams of placebo (oleic acid) per day (low dose)
?????—3.2 grams of placebo (oleic acid) per day (high dose)

WEIGHT REGAIN

CLA did not affect the amount of weight regained during the next three months.

MUSCLE REGAIN

CLA dose-dependently increased regain of fat-free mass (muscle) according to the authors of the study, although it does not appear to be dose-dependent to me.

Fat-free mass increased as follows:

?????—1.6 grams of CLA regained 6.2 percent of their body weight as muscle: 7.3 pounds of muscle.
?????—3.2 grams of CLA regained 4.6 percent of their body weight as muscle: 3.1 pounds of muscle.
?????—1.6 grams of placebo regained 2.8 percent of their body weight as muscle: 5.9 pounds of muscle.
?????—3.2 grams of placebo regained 3.4 percent of their body weight as muscle: 4.0 pounds of muscle.

(The reason the percentages and the pounds of muscle regained may not appear in exact ratios, is that the average starting weight varied between the groups.)

Note: The authors of the study stated that the effect was dose-dependent, however, it does not look that to me. People taking the lose dose of CLA gained more muscle than the group taking the high dose, which is the exact opposite of being dose-dependent.

RESTING METABOLISM

Because CLA increases the amount of muscle regained, it also increases resting metabolism.

?????—1.6 grams of CLA per day increased resting metabolism 12.0 percent.
?????—3.2 grams of CLA per day increased resting metabolism 13.7 percent.
?????—1.6 grams of placebo per day increased resting metabolism 9.1 percent.
?????—3.2 grams of placebo per day increased resting metabolism 8.6 percent.

CONCLUSION

“In conclusion, the regain of fat-free mass was favorably, dose-independently affected by a 13-week consumption of 1.8 or 3.6 g CLA/day and consequently increased the resting metabolic rate,” the authors of the study concluded. “However, it did not result in improved body weight maintenance after weight loss.”

Conjugated linoleic acid (CLA) is naturally found in beef, milk and milk products. It is an intermediate in the metabolism of linoleic acid produced by bacteria.

USUAL INTAKE

In the average American diet people consume about 0.2 grams of CLA per day. (p. 846, col. 1)

REFERENCE

Kamphuis M, Lejeune M, Saris W, Westerterp-Plantenga MS. The effect of conjugated linoleic acid supplementation after weight loss on body weight regain, body composition, and resting metabolic rate in overweight subjects. Int J Obes Relat Metab Disord. 2003 Jul, 27(7):840-47.

Articles on the same subject can be found here:

• CLA (Conjugated Linoleic Acid)