Training on an empty stomach from time to time can lead to big results. Here’s how to do it right. By Courtney Johnson
What it is
The technical term for riding on empty is ‘fasted training’ or IMTG (short for Intra-Muscular triglycerides)– basically, eating minimal to no carbohydrates before (preferably, 8 hours before) a ride.
How it works
During exercise, your body uses two kinds of stored energy: fast-burning glycogen derived from carbs; and fat, which is a longer-lasting fuel source. As you get fitter, your body transports oxygen to working muscles better, making it more efficient. This causes it to get more of its fuel from fat at the same pace.
Proponents of fasted training claim that forcing the body to burn fat in the absence of carbs makes it use energy more efficiently over time, which helps glycogen stores go further when your tank is full. They also say it can prime your muscles to stock more glycogen when you do carb up.
How to do it
Ride before breakfast, says Asker Jeukendrup, sports nutritionist and exercise physiologist at Loughborough University in the UK. Your body is in a glycogen-depleted state, so it’s ready to resort to fat for fuel. Go no longer than 60 to 90 minutes, at a moderate effort – you should be able to hold a steady conversation without gasping. Going harder requires the body to dip into glycogen, and you’ll bonk more quickly.
After your ride
Restock carbohydrate stores promptly – aim to eat a meal with a four-to-one carb-to-protein ratio (like a croissant with peanut butter) within 30 to 60 minutes of finishing the ride. Rehydrate within 60 to 90 minutes.
When to stop
Fasted training requires extra recovery time; overdoing it can lead to injury or illness. Do these workouts just once or twice a week when you’re mostly riding long and easy, says Jeukendrup. If you start racing or doing a lot of intense rides, it’s time to cut it out of your routine – even the fittest riders need carbs to train and ride hard.