Carbohydrates = More Fat Loss?

This post comes from a discussion I found myself in on a prominent online fitness forum. I offer the original author a mechanism by which a higher carbohydrate could promote greater fat loss than a lower carbohydrate diet presuming calories were the same across both diets.

In my client roster, I’ve found that active populations suffer and fat-loss worsens under chronic low-carb conditions, presuming caloric control.

Why? Dietary carbohydrate provides the most bang for the bang in fueling the ATP or phosphagen system. Under resistance training conditions – what amounts to high intensity activity – carbohydrate is the preferred substrate. Chronic insufficient availability of carbohydrate in the form of muscle glycogen has crippled a-many trainees progress in the gym. Moreover, carbohydrate nets a greater thermogenic effect upon consumption, and under overfeeding conditions, is more difficult to store as fat in the body. Beyond that, it looks like less than about 130g of daily carbohydrate causes a down-regulation of thyroid output.

Note that the anaerobic energy pathway, otherwise known as glycolysis, creates ATP exclusively from carbohydrates, with lactic acid being a by-product. As exercise intensity increases, the body relies more and more on carbohydrate metabolism.

So, quick thought experiment. Trainee walks into the gym. Is overloading on fat, all the while under-carbed. His training session nets a 300kcal burn. Contrast this with someone sufficiently carbed, with a lower fat intake. His training sessions nets a 400kcal burn due to greater loads lifted, improved recovery, and more repetitions performed.

Boom, greater potential for fat loss through indirect mechanisms. To be clear, I’m not saying that a higher carbohydrate diet is always going to net greater fat loss than a fat-based diet, but for certain athletic populations they’ll need more, not less carbohydrate than the typical inactive American.

Tagged as: diet, low carb