Very long rides & quick weight loss
 

I rode a 600k brevet this weekend. Took a lot of care to eat and drink enough throughout the 30+ hours of riding. At the end of the ride, I was tired (mostly due to lack of sleep), but never felt depleted. Weighed myself at the end of the ride -- down five pounds. Ths may not seem like a lot to some of you but it is 3.5% of my body weight so it's a lot to me. At 9% body fat, I can't lose 5 pounds through normal workouts, nutrition, etc. Since I was not hungry or thirsty at any time during or after the ride, where did the weight loss come from? Will the weight rapidly return as my body recovers over the next few days.

That's water weight. You can lose water without being thirsty, it happens to me a lot on rides.

My guess is it is mostly water loss. You burned up a lot of glycogen which uses water when it is converted and did a lot of sweating. A little fat and a little muscle loss as well. 30 hours is a lot of riding give it a couple of days and I bet it comes back no problem maybe a pound or two lighter when it is all said and done. You did a lot don't downplay the toll it took on your body.

Congratulation on completing the 600k brevet. I have never rode a brevet, but I used to run marathons and would lose a lot of water weight on long runs and races.

Water weight. Just drink quite a bit over the next few days and you'll be fine again. Oh ... as you start to drink more in the next few days you may discover that your ankles will swell, but don't be worried, that will pass too.

BTW - congrats on the 600K ... I'll be doing my 5th in a couple weeks. :)

Liver and muscles hold sugary water. Their glycogen stores. Its what you got in you that keeps you from bonking, aside from whats in your gullet. Your muscles burned the sugar and water to keep you going, and sweated the rest of the water out. Eat carbs and drink water, and the weight will come back. Mostly. Cause in a 30 hour ride, you're also gonna be burning protein. I'd be eating alot of protein as I recovered.

Thanks for the tips. I drank a bit more than usual yesterday and the weight has already come back after 24+ hours. My confusion was, if I drank enough water during the ride so that (a) I wasn't thirsty afterwards, (b) I didn't bonk, and (c) my urine wasn't bright yellow (one indicator of dehydration), how could I be down 5 lbs? The answer, as you folks informed me, is that the temporary weight loss comes mostly from water loss nonetheless.