I have written about my own personal weight loss on any one of my bikes over the last few years. I started out at 170 pounds, dropped down to 149 and then ran my weight back up to 170 at my wife’s request. Now, I may weigh exactly what I did when I started cycling but the weight is distributed differently. I was a runner prior to cycling and I used that to drop from 195 pounds down to 170 but my legs were still less than stellar. After three years of cycling they’re tree trunks of awesomeness. Guessing, five to ten pounds that used to be elsewhere on my body in fat are now concentrated in my quad, glute and calf muscles.
I have a problem though… Popular thinking is that there’s a “fat burning zone”. Getting to that zone is actually quite easy because the target heart rate is only slightly higher than a warm-up pace. This should be fantastic news, especially for those folks who would rather the “Minimal Effort” option of losing weight and getting fit. Here’s my problem: I don’t buy it.
Perusing the web this morning I ran into a compelling article that supports my suspicion that if you want to lose weight, regardless of the mode of propulsion, the best way to do it is to get after it, hard. Now we can’t go hard all of the time, but I don’t like the notion of “hitting the fat burning zone” either. Allow me the dalliance of explaining: While, it appears to me, the article gets the calorie counts wrong (at least for cycling) it does go a long way to explaining one of my long-time suspicions:
So you have gone out at your medium pace (approximately 60% of VOmax) for an hour and burned 400 calories, primarily fat, good work. After the workout you are hungry so you go grab some food… Well, your carbohydrate stores are mostly full because you didn’t use any… Better store most of that 500 calorie meal as fat… Wait what?
Your body is designed to use what it needs, and if it doesn’t need it it will store it as fat until it does.
You go as hard as you can for an hour and burn over 1000 calories, primarily carbohydrates, hard work. After the workout you are hungry so you go grab some food… Well, your carbohydrate stores are depleted because you primarily used them… Better store most of that 800 calorie meal (you are more hungry than example 1 because of the hard workout) as carbohydrate.
1000 calories – 800 calories = 200 calorie net loss = good = weight loss.
Additionally, when you workout that hard you continue to burn calories long after the work out has ended.
Now I’m not trying to say the fat burning zone won’t work for some people, clearly it can. What I take issue with is the notion that finding the best way to lose weight on a bike. First, managing my weight when I was all fast all of the time was much easier. I had to eat a lot more and was perpetually hungry (which helps) to maintain my weight at 160. This year I’ve incorporated many more slow speed rides (16 mph average which would be right around that fat burning zone) and have had to watch at times how much I was eating. I’ve managed to keep my balance and my weight steady, I just had to be a little more careful to do it. In summation, if I have to be more careful and eat less, it would make sense to come to the conclusion that slower speeds don’t burn off more weight (or fat).
Where this gets interesting is when we factor in top speed. I’m clearly faster this year, there’s no doubt about it. I’m up more than one mile per hour on my Tuesday night club rides, consistently. Part of this might have something to do with my bike (my “aero” Venge is said to be 45 seconds faster over a 40 k than my old 5200)… But that’s only good for about 1/3 of the increase. The other 2/3’s is all me, baby and it was completely unexpected. I was certain I’d lose a little speed for the one or two slower days a week I’ve taken this year even though a lot of the evidence points to at least one slow ride a week being beneficial. Of course, the last time I read about mixing slow rides in with the hard days, I picked up a quote that’s stuck with me since, “Your slow rides should be slow enough that you’d be embarrassed if your friends saw you riding that slow”. Technically, I have my wife to thank for riding with me… Not only do I not do “embarrassing myself” well, I got to go completely the other way and enjoy those slower rides. Talk about a gift!
To wrap this up, the purpose of this post isn’t to debunk or refute the “fat burning zone” hypothesis, it’s simply to offer another option if that doesn’t work for you. If nothing else, you get to enjoy a lot more speed than you would at 60% of your VO2 Max.
UPDATE: This evening was my perfect example of a good, hard workout… 19-20 mph into the wind, 21-22 with a minor crosswind and 24-26 mph with the wind at my back. Wind speed was 7-10 mph out of the west. With less than three miles to go I puked in my mouth and still managed a 23 mph average over the next mile and a half. Now I did have my minimalist cycling computer for feedback but truthfully, it’s the old puke in my mouth that lets me know that I rocked my butt. If you never have experienced this rite of passage, there’s only one way: try harder.