Low-Carb Diet Danger

Mack, the roadie who asked, said he was successfully losing weight on the popular low-carb regimen, but he lacked energy on longer rides and his snap on hills was abysmal.

In my reply, I told Mack that on a low-carb diet "it's almost impossible to ride well, especially for long distances or at high speeds. After all, carbs are the source of glycogen, the muscles' primary fuel."

My bottom line was this: "Losing weight is only one part of the equation. You also need to maintain power. Excessive weight loss (and carbohydrate depletion) will eventually turn you into a weak rider."

How weak? I never heard a scarier account of what can happen to a cyclist on a low-carb diet than I got from a roadie named Jon. I'm sharing it here to underscore how risky it can be to combine carbohydrate restriction with cycling.

This was signed, Suffering in Seattle.

"I came down with overtraining syndrome while following the South Beach Diet. Much of overtraining is due to not recovering adequately after riding. Recovery depends on getting sufficient glycogen back into the muscles.

"With lack of glycogen, the body goes catabolic. That is, it starts turning protein to carbs for the body to continue functioning. The biggest source of protein is muscle, so the body starts eating muscle.

"I didn't fuel myself adequately for two four-hour rides a week apart. The night after a third such ride, I didn't sleep. I could sleep only 2-4 hours per night for the next five months, even with the aid of prescribed medicine.

"A hormone called cortisol controls the body's consumption of carbs, protein and fats. It also controls the adrenal glands. After two or so hours of sleep, I would wake up with my heart pounding and in a panic. Then, my mind was so
active I couldn't resume sleep.

"It's six months later and I'm still recovering, even after switching back to a diet that has a high percentage of complex carbohydrate, eating a caloric surplus and refraining from any exercise. My sleep has slowly begun improving.

"I was told by several cycling coaches that there is a proliferation of overtraining since the popularity of low-carb diets. They are dangerous for endurance athletes!"

Source: RBR