I have been on the keto diet since Dec. 14 2018 and am having difficulties on longer rides.
I’ve been an adventurous cyclist for many years and am currently training for a 200 mile ride in Kansas on June 1st 2019. The reason I started keto was to gain better endurance for long rides and get off of the high-carb spike/crash cycle.
My issue is that I start rides with good energy and strength, but right around the 2 - 2.5 hour mark I start feeling foggy-headed and have difficulty maintaining a pace that I would normally maintain just fine pre-Keto. The more strenuous I ride, the sooner I reach the plateau. It’s NOT bonking – I would call it a pre-bonk.
I have noticed that my heart rate is higher than most cyclists given the same amount of effort. On rides where my friends are in Zone 2 or Low 3, I am spending a lot of time in high zone 3 and Zone 4. This has always been the case, and did not change after I entered ketosis.
I wonder if I am even sufficiently fat-adapted. I try to limit my carbs to 30g or less per day, but realistically I’m probably in the 30-50g range daily. I do experience the other benefits of Keto – can fast for several hours without crashing, I’ve lost about 5% of my body weight and kept it off, am generally eating healthier and more nutritious foods.
Pre-ride, I will have a teaspoon+ of Lyte Show electrolytes mixed in water. If it’s going to be more than a few-hour ride, I’ve been eating 30g of Generation UCAN Super Starch, a slow-release carb source, to keep the glycogen stores topped off. It does not make a difference with the 2 - 2.5 hour issue.
During rides I try to snack every hour or so, with nuts, sausage, mashed avocado, fat bombs, various keto-friendly snacks. Sometimes a Generation UCAN bar. Sometimes a Bulletproof Collagen bar. I hydrate with a zero-sugar, zero-carb mix that provides some electrolytes.
I don’t measure my ketones in any way. I used the urine strips in the first 30 days, but of course their effectiveness drops off. I have a Keyto on order, but it won’t ship until late April.
I am pretty close to pulling the plug on the keto experiment, because I need to train a lot over the next 7 weeks. Does anyone have any comments or suggestions of things to try? Ask me anything you want clarified. Thanks in advance.