The American College of Sports (ACSM.org) is a professional organization for sport science researchers, educators, exercise physiologists, sports dietitians and doctors. At ACSM’s Annual Meeting (May2024, Boston), more than 4,500 members from around the globe presented their latest research. This summary highlights some hot topics discussed at a session hosted by PINES (Professionals In Nutrition for Exercise & Sport).
Fueling endurance: How much carb is enough?
When athletes consume the recommended 30-90 g/hour of carbohydrate during endurance exercise, they tend to perform better than athletes who fail to maximize their carb intake. Given muscle might be able to take up 120-140 g carb/hour if it can get through the gut, the question arises: Would >100 g carb/hour be even more beneficial? However, in some athletes, these potential benefits come with a higher risk of creating gastrointestinal distress.
Training the gut to tolerate a higher carb intake might take about a month or more. Hence, endurance athletes should routinely practice their fueling strategies during training sessions to figure out their individual fueling and hydration sweet spot. The type of carb (liquid, solid, sports drink, energy bar) used for fuel doesn’t matter as long as the athlete is drinking enough fluid.
Caffeine for performance: how much is enough?
Caffeine is a popular pre-exercise energy booster, with some athletes being more sensitive to caffeine’s effects than others. Approximately 45% of athletes have genes that metabolize caffeine quickly, 45% moderately, and 10% slowly, meaning it stays in the system longer. Despite this, caffeine’s rate of metabolism doesn’t dictate its ergogenic effect; caffeine stays in the system for hours, even among fast metabolizers. There is no other good evidence to suggest other genotypes influence caffeine’s performance-enhancing effects. Given caffeine’s benefits appear unrelated to a specific gene, athletes need not spend money on getting “caffeine genotyped”!
Athletes can simply take caffeine in the form of pills (3 to 6 gm caffeine/kg body weight; 200-400 mg for a 68 kg/150-lb athlete) or drink some coffee (about 150-200 mg/ 12-ounce cup) an hour before exercise—though be aware coffee’s caffeine content is highly variable. For a quicker fix, caffeinated gum (developed by the military) gets caffeine into the system within 15 minutes. Words of wisdom: more caffeine is not better; high doses can hurt perform-ance so plan to keep that upper limit to 6 g/kg!
Placebos are powerful
When translated from Latin, placebo means I shall please. A placebo offers a pleasing effect and can enhance performance in its own right. For example, if you take a supplement that you believe in (it pleases you), the chances are good you will be able to perform better—even if research suggests the supplement doesn’t actually work. The stronger your belief, the larger the effect.
The supplement industry commonly exploits the placebo effect. Some companies make a lot of money off of a supplement proven to not work. That said, all supplements come with risks. Just because it works doesn’t mean it is safe. Use supplements wisely…
Nancy Clark MS RD CSSD counsels both fitness exercisers and competitive athletes in the Boston-area (617-795-1875). Her best-selling Sports Nutrition Guidebook is a popular resource. Visit NancyClarkRD.com for more information.