As we come to the end of the season many people start thinking about getting “fat adapted” and start thinking about getting those long miles in and doing a bunch fasted so fat can be the main energy source and hypothetically become more efficient.
This is a really interesting topic and possibly one we could talk and debate for a few more pages but let’s talk about some main points on utilising a train low (training in a low carbohydrate state) protocol.
How fit are you/how long have you been riding consistently for?
If you’re a new rider the chances are, you’re going to be unfit and your body may not be very efficient at cycling. Which most likely means riding on the road and sticking to Z2 HR or power is going to be very difficult, because as soon as you hit any long drag or hill you’re going to be struggling. Carbohydrate restricted rides require that the intensity stays at Z2 or lower. If the ride has intensity, the potential of you getting through 3+hours without food and maintaining power will greatly diminish.
What is your main objective – what race/event do you plan to do?
Think about what you’re training for, if the event, race, sportive means you will need to eat on it then probably a good idea to train what you’re eating too.
Why? Well it’s obvious really. If you eat fewer carbs and use more fat, as you upregulate your ability to do one, you down regulate your efficiency at the other which will make you worse at using carbohydrate. Not great if you’re going to be eating during your ride.
Doing it to lose more body fat.
First things first. Whether you’re in a calorie deficit fasted ride or not you will not be dropping body fat. If you had two days which were identical in every way; food, activity, calories burn in the ride and type of session and the only difference was one was a fasted the other was fed is it possible to lose more in one than the other? The likelihood is no. Maybe you could lose a little more in the fasted but not significantly so.
There are benefits though.
We do see benefits from carbohydrate restricted training, like increased amounts of mitochondria (aerobic cell) created from these sessions so hypothetically getting more out of those Z2 rides, changes in insulin sensitivity, you will get better at using fat at lower intensities (but it should be done in combination with fed rides).
How would I use it?
I would do one maybe two rides a week carbohydrate restricted. I would make them 2-3 hours (maybe longer if you’re an experienced rider) to ensure you become glycogen depleted, a quick 30-45mins in the morning won’t cut it! This will carry over more to your events as you want to be able to use more fat 3 hours down the line.
Ultimately think about your overall goal, mix them into your sessions but don’t make them all depleted, fuel for hard rides, restrict for easier.