Low Carb Diet for Athletes: Is it worth it?

By: Ms.Fia Batua, RND -CSN EFT | Medical Culinary and Sports Nutritionist Dietitian

Written for Manila Bulletin Crossfit Magazine

It’s true that in the short term, Low Carb Diet (LCD) or Very Low Carb Diet (VLCD) can result in rapid weight loss, about 1-3kg first few days. But this is due to the depletion of glycogen and water loss.

Nonetheless, in the long term, these diets do not seem to maintain faster weight loss compared to traditional energy-restricted plans.

Athletes are naturally carb-burners. And it is important to understand that every time the energy source is depleted, you need to replete.

In a Low-intensity training, an athlete needs 3-5g Carbohydrates (CHO) per kg body weight, and intake of 8-12g CHO per kg body weight for a 1-3hr moderate to high-intensity training.

During moderate-high intensity training, the body is unable to use fat as energy quickly enough, thus requiring carbohydrates to produce or replenish energy. And according to the mainstream diets, an LCD falls to a category where carbohydrate intake is less than <3g/kg BW (<150g per day), or <10% TER (VLCD/VLCKD).

LCD/VLCD also restricts or limits the intake of of whole grains, fruits, and starchy vegetables, in which all are great sources of fiber, essential vitamins, and minerals – increasing the risk of possible deficiency.

Athletes who use LCD/VLCD as a weight management program may result in inadequate nutrients and energy intake, which in return can affect overall performance.

In Sports, carbohydrate intake should be “periodized” or match the training plan where intensity and duration vary.

Summary:

If the goal is to lose weight, it can be achieved by any strategies that consist of lower energy intake correlate to energy used (First law). Low Carb Diets may be beneficial in some situations like injury days/low-intensity activities. But a person or an athlete who trains 1-3hr per day, moderate to high intensity, should include quality carbohydrates to their diet, and athletes should plan their overall nutrient intake to match their training goals and plan.