Branched chain amino acids (BCAAs) - once mostly talked about in body-building circles -are enjoying a rise in popularity with the endurance set, especially among Paleo and other low-carb followers. They extoll these protein precursors as near metabolic superheroes, praising their ability to burn belly fat, quell cravings, improve endurance, build lean tissue, hone mental focus, build immunity, and bypass delayed onset muscle soreness.

Some of that is still up for scientific debate. And it may be a bit oversold. No one macronutrient has all those magical powers. But BCAAs are really important for and have long been overlooked by cyclists and other endurance-oriented folks, especially those who tend to take a more carb-centric fueling approach, says Leslie Bonci, sports nutritionist at Active Eating Advice.

“Too many endurance athletes still emphasise carbs to the expense of other essential macronutrients and that leads to performance problems,” she says. Here’s a breakdown of what BCAAs are; how they can boost your riding game, and how to get what you need.

Protein Building Blocks

Protein Building Blocks
Photograph by Getty Images


BCAAs are essential amino acids (most notably valine, leucine, and isoleucine) that are the building blocks of protein, which in turn are the building blocks of muscle. “BCAAs account for 33 per cent of muscle tissue and stimulate the building of protein in muscle and reduce muscle breakdown,” says professional athlete and exercise physiologist Magdalena Boulet, VP of Innovation, Research & Development at GU Energy Labs.

They also supply fuel for your muscles, especially during hard rides as your glycogen supplies run low. “During endurance exercise, between 3 to 8 per cent of energy needs are supplied by branched-chain amino acids, specifically leucine, isoleucine, and valine,” says Bonci. After exercise, they help with muscle repair. They are “essential” in that your body doesn’t make them. You have to get them through your diet.