If you want to lose weight to get faster on the bike, training when your body is in a low glycemic state is one of the most beneficial habits you can implement into your daily or weekly schedule. This practice is known as fasted training.

What if you could re-engineer your body to function at its peak and burn fat more efficiently by simply tweaking what you consume before a workout? That might sound like an opening line straight out of an infomercial selling a “miracle” weight loss pill, but that’s the science-backed promise of fasted training.

What Happens When You Deny Yourself of Glycogen

The big goal of fasted training is to intelligently deny your body of glycogen so that when you go into a workout your body’s fuel preference is fat. For this to happen, intervention in the way of prolonged periods of glycogen intake needs to occur. Without intervention, your body will not be forced to adapt. As a result, it will seek out sugar (the fuel source it likes best) to feed on during your workout.

When intervention does occur, your body is able to gradually replace glycogen consumption with fat consumption during your workout. This is how all that fat-burning magic happens.

If that’s not impressive enough, fasted training also teaches your body how to improve its metabolism when you’re in a rested state. So while many athletes go into fasted training with the sheer desire to lose fat, what they might not fully realize is how in the process they’re making their bodies better at metabolizing fat across the board — that’s metabolic training in a nutshell!

How quickly this transformation happens is subjective and based on the degree you’ve damaged your metabolism in the past. The metabolism of a person who’s been replacing sugary beverages with water for years, for instance, will adapt more quickly than that of someone who recently gave up heavy soda drinking.

Caffeine’s Role in Fasted Training

It’s common with athletes who use fasted training to drink coffee just before they workout. This is a good idea because, as we all know, caffeine encourages fat metabolism. The trouble is, all coffee, better yet, all coffee creamers are not created equal. In fact, most will reverse the effects of fasted training.

If you’re a coffee drinker who wants to get into fasted training, your only safe creamer option is heavy whipping cream. With heavy whipping cream, we’re talking pure fat — no sugar or lactose. That’s the key.

Even though there’s not a ton of sugar in something like half and half or low-sugar coffee creamers, there’s still some, which will disrupt the entire fasting process if you consume it. Why? Because you’ve just introduced glycogen into the mix.

Your body doesn’t care how little of an amount it may have been. It’s like a shark with blood. The second your body gets a taste of glycogen, it will go for it and leave anything else that might have been desirable to consume for fuel behind. Then comes the most unfortunate part of all: your fat metabolism shuts down. This is what you want to avoid.

If you’re not a coffee drinker and you still want to reap the boosting effects of caffeine, consider taking a caffeine pill 15-30 minutes prior to your workout.

Two Ways Cyclists Can Implement Fasted Training

There are two manageable and smart ways you can implement fasted training into your routine. The first involves doing your workouts earlier in the day after you’ve had a night of rest and before you’ve had anything to eat.

Early morning workouts are typical for those who do fasted training. After 12+ hours of not consuming any glycogen, most people’s liver stores are depleted and their muscle stores have just enough glycogen in them to get the person through a 60-90 minute workout. This is one of the reasons TrainerRoad’s workouts and structured training plans work well with fasted training —they’re all about that duration.

Warning: If you plan on doing a workout that’s more than 60-90 minutes and you’re going into it fasted, be warned. Depletion occurs naturally after a 60-90 minute workout, so I do not advocate doing high-intensity training in a depleted state. Depletion should come prior to low intensity work or post high-intensity work — but not prior to high-intensity work. High intensity work absolutely needs to be fueled if you want to reap the maximum benefit from your workout — you can’t do that in a glycogen depleted state.

Once your muscle stores are deficient of glycogen, you can expect to hit a wall in your workout, unless your intensity stays fairly low. How soon until that fatigued feeling consumes you will depend on the intensity of your workout. Because lower intensity workouts require less and sometimes very little glycogen, you’ll likely be able to last well past that 60-90 minute period without introducing fuel on the bike.

If you ever find yourself in this position, be very mindful to how you’re feeling and don’t be afraid to bail out of your workout if you need or introduce some quick-digesting carbohydrate into the mix. Something like a sports drink or even a gel washed down with plenty of water should do the trick. One way to tell you’ve crossed that line is the smell of ammonia on your breath.

The second way you can implement fasted training into your routine is by doing two-a-days, i.e. completing two workouts in a 24-hour timeframe. If you’re the type of athlete who feels like they can’t get their best high-intensity workouts done in the mornings, this is probably your best option. I know it is for me.

In the mornings, again before you’ve had anything to eat except for maybe a cup of black coffee, do a soft-pedal workout for about 30 minutes — we recommend the workout “Dans” for this — to reap the benefits of fasted training. Then, in the afternoons or evenings complete your higher intensity workouts. If two-a-days sound like something you might like, start by giving it a try three times a week right out of bed and see how you feel.

Final Words

While fasted training might not be as easy as taking a “miracle” diet pill to lose weight, it’s surely effective. When you practice fasted training not only will your body burn more fat during your workouts, it’ll also become programed to favor fat as its fuel source even when you’re off the bike. But just like any other training tool, fasted training has its place and should be used only when the time is right.

Listen to Certified Cycling Coaches Discuss Fasted Training

“How cyclists can use fasted training” is one topic we covered in episode 23 of the Ask a Cycling Coach podcast. Listen to the episode’s full recording below to hear this and other questions from cyclists get answered by our certified cycling coaches.

Additional Notes

TrainerRoad’s Ask a Cycling Coach podcast is dedicated to making you a faster cyclist. It gives you the chance to get answers to your cycling and triathlon training questions from USAC certified coaches Chad Timmerman, Jonathan Lee and special guests. Learn more about other topics we covered in the latest episode with our resources below:

  • How to use a heart rate monitor for calorie burn
  • What time of day is best for training?
  • How to taper for a race
  • Is it a good idea to get a massage before a race?
  • Using base training to lose weight
  • How to use fasted training for cyclists
  • How to get stronger in the flats
  • How to analyze your pedal stroke
  • How to use heart rate for indoor training
  • Why is my heart rate different when training indoors?
  • Should you take an FTP test indoors or outside?

For more answers to your cycling training questions, listen to Ask a Cycling Coach — the only podcast dedicated to making you a faster cyclist. New episodes are released weekly.

Getting Faster with TrainerRoad

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Chad Timmerman

Chad Timmerman is the Head Coach and Co-Founder of TrainerRoad — cycling’s most effective training system. He has nearly 10 years of coaching experience as a Level I USA certified Cycling and Triathlon coach. When he’s not developing structured training plans for TrainerRoad, you can catch him sharing his coaching advice on the Ask a Cycling Coach podcast. To get Chad’s best cycling knowledge delivered to your inbox, sign up for our email list.