Can I perform on a Low Carb High Fat Diet?

A Low Carb High Fat diet (LCHF) such as Paleo, Banting and Atkins is all the rage at the moment. Can you race and perform on such a diet though?

Well, I think it depends on who you talk to. In my opinion you can definitely train on on a Low Carb High Fat diet. Racing depends on a couple of things, such as the type of race, duration and how fat adapted you are.

One of the best resources on the subject I have found is a book “The Art and Science of Low Carbohydrate Performance” (by Steve Phinney and Jeff Volek). These guys have been researching the topic of Low Carb High Fat diet and endurance sport performance for a long time and in their opinion it is very possible to perform on a low carb high fat diet.

My Experience on a Low Carb High Fat Diet

I found (as was to be expected) that at first my performance definitely took a big dip. The first couple of weeks, especially the first couple of days were very hard. I had zero energy. After a while though my body did become more fat adapted and as long as I did not push myself into the red (anaerobic zone) I was fine. The overall improvement in terms of weight loss and energy levels over a couple of weeks were remarkable though. After about two weeks training at anything but really hard efforts became easy and very enjoyable.

I completed a number of multi-day trail running and multi-sport events on a LCHF diet and I think it works for me. I still battle with sugar cravings and occasionally succumb to the temptation. My overall fitness levels and general health is very good and I have more energy than before.

Some Help From My Friends

I stumbled on VESPA Power, an amino acid supplement that worked really well for me on a LCHF diet ( VESPA assisted my body to metabolize fat at higher intensity levels.

What are the pros doing?

Many pro athletes (including some pro continental cycling teams) now use a middle of the road strategy of train low (carb intake) and race high (carb intake). If you have to push into the red during your race this might be an option.

Race Duration and a Low Carb High Fat Diet

During long races you will need to supplement with carbs if you are not fat adapted. Your body can only store a limited amount of carbs. Your fat stores are vast however and so if you are fat adapted and can use your fat stores and will be less reliant on carb supplementation and you will be able to go longer and feel better.

Race Intensity and a Low Carb High Fat Diet

Intensity is the killer though. The higher the intensity the less the body’s ability to burn fat (unless you use something like Vespa Power). You can however through conditioning make your body “better” at burning fat and to some extent overcome the intensity issue.


My suggestion is to try LCHF if you are battling to keep the weight off even though you are active. Stick with it for a couple of weeks, it is hard in the beginning. Don’t cheat, if you do you will not transition your body from preferring carbs to burning Ketones, and do your research, many will tell you that you are going to die of a heart attack which is an unsubstantiated claim…