Most bodybuilders reduce carb intake when they’re trying to get lean. Some bring their carbs down to almost zero, while others take a more moderate approach. In most cases drastic reductions in a macronutrient will cause ill health; however, for short periods severe restriction can cause a big shift into lean-machine mode. For example, the Atkins diet recommends a few weeks of taking in only about 35 grams of carbs a day to train the body to burn fat as opposed to sugar for fuel, and then carbs can be gradually reintroduced—up to a point. I’ll elaborate on that break point in a moment.
First, the case for curbing carbs. In an interview that appeared in Bottom Line Yearbook 2009, award-winning science journalist Gary Taubes says carb control is the best strategy for weight loss:
“Our fat tissue is regulated by our hormones, the hormone insulin in particular. The higher your insulin level, the more calories your body will store as fat…and the more difficult it will become for your body to rid itself of this fat. The more carbohydrates in your diet, the more insulin your body will secrete…. So the big secret to weight loss is not simply to eat less or to exercise more—it is to consume fewer carbohydrates.”
In a previous item, “Carbohydrate Conundrums” [Eat to Grow, November ’10], I made the case for dieting bodybuilders to get about 150 grams of carbs a day—to maintain health and glycogen stores and to keep fat burning at full tilt. That number is a good place to start because the human body stores a total of only about 350 grams of glycogen in liver and all the muscles combined. A hard workout that hits a few bodyparts will deplete only about 100 grams at the most. Replenish that 100 and add another 50 grams for general health and systemic needs, and you have 150 grams a day.
There’s also a big health reason to keep your carbs fairly low. Back to Taubes: “Despite all we’re told, there is little evidence that high-fat diets cause heart disease. The evidence is far more compelling that high-carb diets are to blame. In fact, when you actually look at the studies evoked to support the benefits of low-fat or low-saturated-fat diets, which no one bothers to do anymore, you find just as much evidence that these diets cause heart disease as that they prevent it.”
The reason is that excess carbs are converted to triglycerides in order to be stored as fat—and triglycerides can cause heart disease.