Question: Last winter I adopted a low-carbohydrate diet and lost 20 pounds. I’m continuing the diet but wonder if lack of carbs is the cause of my struggles on the bike. While I’ve improved my average speed on solo rides, I can’t keep up with my friends on Sunday morning. I’m fine when the pace is steady, but if they sprint I’m off the back. How do I maintain low body weight and still get the necessary fuel? — Tom D.
Coach Fred Matheny Replies: The research is pretty clear on a low-carb diet. It might help you lose weight quickly, but it doesn’t provide enough carbohydrate to keep your muscle glycogen level sufficiently high for performance riding. It doesn’t help to lose 20 pounds if you end up slower rather than faster!
The reason your average speed has improved but you can’t stay with the group is simple.
When you don’t have carbs to burn, your body primarily runs on fat. It can simmer along steadily, but it can’t go fast because high intensity requires lots of glycogen.
When your buddies pick up the pace, you don’t have “afterburners” that allow you to jump quickly and stay with them.
I suggest increasing the percentage of carbs in your diet. Add whole grains, fruits and veggies. Reduce fat and protein slightly so you aren’t taking in more total calories and gain weight.
I bet you’ll feel better and perform better, too.
Mike says
Hi, I’m a cyclist and have been on a slow carb diet. I’ve noticed the following.
During the first 3 rides since slow carbing, I literally ran out of energy after 30 minutes. The first time, I had protein-rich foods to snack on and they didn’t help much. After that I packed pure carbohydrates (Clif’s Blocks) and they helped significantly. Since then, I always bring carbs just in case, but I haven’t needed them on rides up to 2 hours, though the last 20 minutes or so are a little slower than they’d be with carbs. Also, taking carbs while riding didn’t seem to reduce my fat loss.
Ned B says
Too many studies based on people that just adopted a low carb diet and haven’t reached the level where they body isn’t relying on carbs anymore. There are several studies now that prove a low carb endurance athlete doesn’t have the “bonks” that a higher carb diet athlete has. So do better research based on more valid studies.
Hal says
Look up Chris Froome. He did low carb to train and lose weight and so he was cycling while on low carb diet during training. But then for the race, adn preparing for the tour, they todl him to switch to high carb, where he even consumed 100g carb/hr. So, low carb is good fro losing weight and even training (good for endurance), but if you’re competitive, you may want to up the carbs on the day you have a competitive ride. So, that you don’t mess up your metabolism and stomach (Chris complaiend that it was hard on his stomach do such hig carb so fast – 100g carb/hr), just go a lttle higher that day. Find out waht your number is.
There’s studies showing that athletes can stay keto at higher grams per day than 20g, because they are burning so much through excercise. I have personallly found this to. My number was about 40-50 g/day when I was very high in excercise time, and about 30 g/day when i was lower in excercise, and if i didnt excericse for a few days it was around 20 g. Your body is a different weight and your excercise time is also different than mine. Find your numbers. For the competitive days you should go a little higher than your stable numbers if you want the extra glycogen sotrage. But yes, i felt the same as you’re saying in group rides when i was keto (<15 g carb/day and excercising).