Very low carb absolutely kills sports performance. I did a very low carb diet one season prior to bicycle racing. Got lean as could be. Then I entered a race series in the Midwest and...lo and behold...got dropped every time the race pace shot up. Was dying to finish a lousy 20 mile race, lol.
The series lasted a week so on day 2 I went to the grocery store and bought every easily digestible carb there was. Two days later I got 3rd place in one of the races- a 30 mile race run at 27 mph.
A long slow effort aerobically, like riding 100 miles, can easily be done on very low carb. I did training rides like that. Pace was about 15 mph. Try doing that same distance at race pace- 25 mph+- in a pack and you will be dropped on the first acceleration. Aerobic sports are definitely high carb.
I'm currently dieting and dropped my daily intake to 2000 kcals. I'm losing about 1.5-2 pounds a week. My carbs are at 200-250 g a day.
Maybe, maybe not. The jury is still out.
Impact Of Ketogenic Diet On Athletes: Current Insights2019 Nov 15Whether nutritional ketosis yields any tangible performance benefits to athletes is a contentious subject within nutrition science. This academic debate has brought about several investigations in an array of athletes, including endurance athletes, resistance-trained athletes, and CrossFit trainees.
The impact of a ketogenic diet (KD) (<50 g/d carbohydrate, >75% fat) on athletic performance has sparked much interest and self-experimentation in the past 3–4 years. Evidence shows 3–4-week adaptations to a KD in endurance-trained athletes were associated with maintenance of moderate (46–63% VO2max) and vigorous intensity (64–90% VO2max) endurance exercise, while at intensities >70% VO2max, increases in fat oxidation were associated with decreased economy (increased oxygen consumption), and in some cases, increased ratings of perceived exertion and heart rate. Two investigations in recreationally active endurance athletes noted no vigorous intensity exercise decrement following 3- and 12-week adaptations. Moderate (70–85% one repetition maximum) and near-maximal to maximal intensity (>85% 1RM) strength performance experienced no decrement following a 3-12-week KD adaptation. Beneficial effects were noted for 2000 m sprint and critical power test completed for short duration at vigorous intensity, while two additional tests noted no decrement. For sprint, near-maximal exercise (>91% VO2max), benefit of the KD was observed for six-second sprint, while no decrement in performance was noted for two additional maximal tests. When protein is equated (grams per kilogram), one investigation noted no decrement in muscle hypertrophy, while one noted a decrement. One investigation with matched protein noted the KD group lost more body fat. In conclusion, moderate-to-vigorous intensity exercise experiences no decrement following adaptation to a KD. Decreases in exercise economy are observed >70% VO2max in trained endurance athletes which may negate performance within field settings. Beneficial effects of the KD during short duration vigorous, and sprint bouts of exercises are often confounded by greater weight loss in the KD group.
With more athletes pursuing carbohydrate-restricted diets (moderate and strict (KD)) for their proposed health benefits, more work is needed in the area to address both performance and health outcomes.Short-Duration Vigorous Intensity (64–90% VO2max, >30 s)Evidence suggests
no decrement to short-duration vigorous-intensity exercise
following 3–12 weeks of a KD within trained and recreationally trained athletes.
Findings are contrary to sports nutrition guidelines, which recommend carbohydrate availability to enable vigorous performance.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6863116/
