USEFUL: Branched-chain amino acids for fat loss, lean mass, and greater lifespan.

Researchers used to talk a lot about all of the BCAAs, but it’s now understood that only one of them is truly critical: leucine.

Leucine is the most important nutritional signal for muscle protein synthesis. It does this by activating the mammalian target of rapamycin (mTOR). . . .

As leucine rises, mTOR is stimulated, and muscle protein synthesis increases. The area under the curve for blood leucine after whey ingestion was ∼73% greater than soy and ∼200% greater than casein. . . .

Leucine can actually cause greater burning of fat and hence fat loss. A nutraceutical containing 2.25 grams leucine, along with 30 mg vitamin B6, taken twice daily, caused the loss of nearly two kilograms of fat on a caloric maintenance diet, and on a hypocaloric diet (500 calorie a day deficit), subjects on leucine and B6 lost twice as much fat, 5 vs 2.3 kilograms, as the placebo group.