Carbs: The Anabolic Nutrient
Carbohydrates can help you pack on muscle — or bodyfat — depending on when, what and how much you eat. Here’s what carbophobes and carboholics need to know about this important macronutrient for optimal physique gains.
Author: Dwayne N. Jackson, PhD; Photographer: Robert Reiff; Model: Josh Bergeron
Ask 10 bodybuilders about the importance of protein for muscle building and you’ll get unequivocal support. Ask the same group about the value of carbohydrates and you’ll likely get 10 different answers. Among the macronutrients, no other has faced more scrutiny than carbohydrates. In fact, over the years nutritionists and diet specialists have spoken out of both sides of their mouths about “carbs,” claiming they’re everything from beneficial (i.e., give you energy) to evil (i.e., make you fat) — a debate that leaves most of us confused about where carbs fit into a bodybuilding diet.
There are several reasons for the confusion and contradictory advice. First and foremost, not all carbohydrate sources are created equal, and different forms of carbs cause several different reactions in the body. Second, research is only just starting to unravel the benefits and caveats of carbohydrate ingestion in its many different forms. As a serious bodybuilder, you understand how critical it is to find the right balance of protein, fats and carbohydrates in your nutrition plan. In this article, MuscleMag removes the question marks surrounding carbs with a comprehensive overview of the what, when and how for successfully including carbohydrates in your diet and supplement regimen, both to build muscle and lose bodyfat.
The Science of Carbs
Carbohydrates are so named because they’re made up of carbon, hydrogen and oxygen atoms (or hydrated carbon). These compounds serve many functional roles in the body beyond food energy. For example, ribose sugar comprises the backbone for the genetic RNA and is also important in the formation of many coenzymes. For the purposes of this article, however, we’ll focus specifically on carbohydrates as food or supplement sources for bodybuilders.
For a fast-acting source of energy, carbohydrates trump both fat and protein because sugars are more easily and readily metabolized than the other macronutrients. The amount, type and rate of digestion of different carb sources dictate the level of blood glucose and amount of insulin released by the pancreas. Insulin is a hormone that delivers excess blood glucose to be stored in muscle cells and the liver as glycogen. Once glycogen levels are topped up, the remaining blood glucose is converted to fat and stored in fat cells. The fact that insulin is integral to driving nutrients into skeletal muscle makes it one of the most potent anabolic agents and the focus of many research studies in exercise science. Insulin sensitivity (the body’s ability to use insulin) greatly increases in trained individuals, especially right after training. In contrast, insulin sensitivity declines in the evening.
Getting past all the science, the main point to deduce is that depending on the state of nutrition and timing of intake, high blood sugar and insulin levels could lead to either desirable or undesirable outcomes. Ideally you want to spike blood sugar and insulin levels at opportune times to take advantage of energy storage and anabolic effects while avoiding fat storage.
These are the simplest class of carbohydrates, as they can’t be hydrolyzed any further to form a simpler sugar. Simple-carb sources taste sweet and include glucose (dextrose) and fructose (fruit sugar). Glucose is absorbed high in the gastrointestinal (GI) tract and thus elevates blood sugar and insulin rapidly and greater than any other carbohydrate form. Fructose, on the other hand, digests low in the GI tract, has a relatively minor impact on blood sugar levels and is considered a slow carbohydrate.