Dietitians Warn Fasted Workouts Carry Risks, Show Little Weight-Loss Benefit

1 articles · Updated · TODAY · Jul 24

Dietitians say exercising on an empty stomach may burn more fat during a session, but shows little evidence of producing greater long-term weight loss.
Lower insulin can push the body to use stored fat, yet experts say overall diet quality, calorie intake and consistent exercise still drive weight management more than workout timing.
Rizzo recommends eating before almost every workout, especially weights, HIIT, running, cycling and other endurance exercise; only easy walks or gentle yoga may be reasonable to do fasted.
Certain groups face higher risk — including people on insulin or other blood-sugar-lowering drugs, pregnant people, those with fainting or disordered-eating histories, and athletes training for multiple hours a day.
Warning signs such as dizziness, shakiness, nausea, blurred vision or confusion mean stopping, taking 15-20 grams of fast-acting carbohydrates, and waiting about 15 minutes before resuming.