Lighter means faster, right? Not necessarily

Losing weight to improve athletic performance is not a one-size-fits-all equation, preliminary research from the Cardiovascular Performance Program at Massachusetts General Hospital suggests. Athletes in endurance sports may think dipping below normal BMI will help them compete, but existing data are mixed — and focused on men. When the researchers studied 805 women and 1,419 men who ranged from non-athletes to pros, they found that for men of all ages and women 30 and older, aerobic fitness declined with increases in BMI. But women under 30 with the best aerobic fitness had an average BMI of 23.2, at the high end of recommended BMI. These early results from an American Heart Association virtual meeting don’t show cause and effect, but could inspire further studies, given the risks for athletes consuming too few calories.