Kelsey Higginson's 1:1 rule: eat one gram of carbs for each minute between waking and your workout. A 60-minute window means 60g of carbs (try a granola bar or half bagel), then eat a full breakfast after.
Okay, athletes, how do you fuel before an early morning swim or run? Use the 1:1 rule. For each minute you have before practice, you're gonna have that amount of carbs. So if you wake up at 5:00 AM for a 6:00 AM practice and you have 60 minutes before your practice, you're gonna have roughly 60 grams of carbs. And then you can save your big breakfast for after practice. But before practice, you just want some carbohydrates. So if you wake up at 5:30 for a 6:00 AM practice, immediately have about 30 grams of carbs, which could honestly just be like a granola bar or half of a bagel.