Do Ketogenic Diets Hurt Or Help Performance?
Very low carbohydrate ketogenic diets (VLCKD) are becoming an increasingly popular method for weight control worldwide. A recent study performed in Italy researched the effects that VLCKD had on sport performance. The aim of the study was to investigate the influence of VLKC on explosive strength performance.
The study recruited 8 elite artistic gymnasts and analyzed their body composition and various performance aspects before and after 30 days of a modified ketogenic diet. The performance aspects analyzed were: hanging leg raise, pushups, parallel bar dips, pull ups, squat jumps, countermovement jumps, and 30 seconds of continuous jumps. The athletes continued with their normal training, and after three months tests were performed again.
The modified ketogenic diet was mostly made up of beef, veal, poultry, fish, raw and cooked green vegetables without restriction, cold cuts (dried beef, carpaccio, and cured ham), eggs, and cheese (such as parmesan). The drinks allowed were infusion tea, moka coffee and herbal extracts. The foods and drinks that athletes avoided on the VLCKD included alcohol, bread, pasta, rice, milk, yogurt, soluble tea, and barley coffee. After the VLCKD trial, the athletes consumed their usual diet which consisted mostly of potatoes, whole grains (bread, pasta, whole wheat, and rice), meat and poultry, eggs, vegetables, legumes, fruits, olive oil, whole milk, and wine. This diet was very similar to a Western diet. Just as in the VLCKD, the athletes were analyzed before and after the 30 days of the diet.
The results of the study indicated that there were no significant differences in body measurement variables or in the basal athletic performance that was detected before either trial. However, comparison of measurements before and after the VLCKD shows a significant reduction in body weight, fat mass, and fat percentage, and an increase in lean body mass percentage. There were no significant differences pre and post the Western diet trial. After the VLCKD trial, muscle mass and lean body mass remained relatively the same.
The results of this study suggest that power and strength performance can be maintained on a VLCKD, despite the rapid weight loss. To date, only one study has been published that examined the effects of a VLCKD on exercise, and the results of that study reported no difference in strength isometric performance between a VLCKD group and a high carbohydrate group, which is consistent with what was found in this study.