Having been around many different types of athletes, the one thing that’s always stricken me as odd is that many endurance athletes are nowhere near as lean as one would expect, in comparison to other athletic populations, based on their relatively healthy diets and high training volumes. Don’t get me wrong, most of us are nowhere near “fat" either, and some of us are extremely lean, it’s just that as a group we’re not as lean as one would expect.
There are all kinds of theories as to why this is the case. Some have even proposed that endurance training encourages greater fat storage. Now I’m not so sure about this, but there is new research which supports another theory.
A clinical trial by Dr. David Ludwig of Boston Children’s Hospital published last week in The Journal of the American Medical Association examined the effects of three different dietary protocols and the results are surprising: a high-carb, low-fat diet; a more minimally-processed, non-starchy, moderate-carbohydrate diet; and a very low-carb, high-protein, high- fat diet.
As summarized by Gary Taubes, NY Times:
The fewer carbohydrates we eat, the more easily we remain lean. The more carbohydrates, the more difficult. In other words, carbohydrates are fattening, and obesity is a fat-storage defect. What matters, then, is the quantity and quality of carbohydrates we consume and their effect on insulin.
From this perspective, the trial suggests that among the bad decisions we can make to maintain our weight is exactly what the government and medical organizations like the American Heart Association have been telling us to do: eat low-fat, carbohydrate-rich diets, even if those diets include whole grains and fruits and vegetables.
The research was conducted on obese subjects, but it’s not a big stretch to see how it can be applied to leaner, more active individuals. Due to our high activity levels, we’re constantly encouraged to follow diets rich in starchy carbohydrates. Thus, many of us consume a disproportionate quantity of cereals, breads, pastas, and other grain-rich foods. Unfortunately, this may be the very thing keeping us from becoming leaner and thus performing better.
It doesn’t makes sense for runners and cyclists to go to the Atkins-diet extreme. Our activity levels warrant greater carbohydrate intake. The take home message is that if you’re not as lean as you’d like despite consistent training and maintaining dietary discipline, you may benefit by cutting back (not eliminating) starchy carbs in favor of non-starchy vegetables, fruits, protein sources, and healthy fats.