–Mao Zedong (Mount Liupan)
Over the last few years I have heard and read a lot of people who insist that exercise is dependent upon carbohydrates to some degree or another. Some of them will assert that this is the case for just about any exercise other than taking a leisurely stroll, such as these guys at the bodybuilders.com website:
If you’re someone who hasn’t seen a slice of bread – or any other carbohydrate for that matter for at least a few weeks, attempting to do HIIT is going to be downright disastrous. Not only are you going to set yourself up for the loss of lean muscle mass, but chances are you won’t make it through the workout.
You simply cannot workout at the intensity required by HIIT without glucose in your system and if you don’t have carbohydrates in the diet to any extent you will not have the resources to complete the session.
I think the quote above is nonsense. So does this guy (whose comment appears halfway down the page):
As someone who completes high-level crossfit workouts 5 days a week, always in a fasted/ketosis state (I do have a cup of yerba mate or coffee w/ coconut oil when I wake up), I can honestly say muscle mass loss is not a concern.
If you wanted to waste an afternoon you could easily find forums where people will argue about this endlessly. Like this one! (HIIT, by the way, is High Intensity Interval Training. There’s not a lot of consensus on what exactly qualifies, but here’s the Wikipedia entry about it if you’re curious. “High” intensity is a bit of a misnomer. What it really is is nearly maximum intensity in bursts.)
Back when I used to eat plenty of carbohydrates, I could do almost precisely nothing. I agonized my way through fifteen to twenty minutes on this dumb elliptical we bought, solely because They said that it was essential for my health. I’ll never forget the day a visitor from the States was taking the tour of my home, looked at that machine, and said, one eyebrow raised, “Do you use it?” If I were a smarter person that would have been my clue right there: how could something be “essential” and “good for me” and “healthy” if it wasn’t making the slightest difference?
Anyway, fast forward to the miracle of realizing that skim milk, homemade wholegrain bread, and fruit smoothies were not good for me. I started eating pounds of butter and suddenly felt like doing things. I threw away the elliptical (an enormous space-waster anyway). Now I go to the gym once every a week or two and spend fifteen minutes moving a lot of weight very, very slowly until I have completely emptied the glycogen stores of my muscles and can barely stand or even hold up a pen. This is “high intensity.”
The second thing I do is more like fun. No one told me to do it. I didn’t read about it. It’s just what I feel like doing. What I did when I was a kid. I’ve found a place where nobody ever is, and I go there. Sometimes I just walk. More often I walk till I feel like sprinting. Then I take off like Woman #3 extra in Godzilla. I run for about twenty seconds till I sense that I’ll trip and kill myself if I don’t stop. Then I run lightly for a bit because walking is too slow. Sometimes you just like to get there faster. Then I run hard again.
I did this tonight, in fact. I decided to do it for the blog. The timing was perfect. For a totally other reason, today I just happened to keep exacting track of my fat, protein, and carbohydrate intake. I ate 166g of fat, 53g of protein and 18g of carbohydrate, and that carbohydrate had been ingested long before I went out to run. There was no carbohydrate for my body to run off of: could I manage high intensity bursts of exercise in the HIIT vein without any carbohydrate?
I was out for around thirty minutes. During that time I sprinted to exhaustion four times and spent quite a bit of the in-between time running at a lower intensity and walking quickly on both ends. Just for fun I got this heart rate app for my iPod, and according to it my heart rate during sprinting was exactly ideal for a woman ten years younger than I am. I’ve been inside now for an hour. Guess what I’m not? Hungry. Or tired.
I’m just sayin’. Don’t give me a medal for my dedication to fitness. I have no dedication to fitness. This isn’t the result of diligent exercise. This is the result of butter, coconut oil, free range eggs, and grass-fed beef. And this is why I think the notion that you have to have carbohydrates to do short bursts of intense exercise is hogwash. Maybe if you’re addicted to carbohydrates you need it, but I’m not and clearly I don’t. It’s N=1, this little test, which means it can’t prove that no one needs carbs to exercise intensely. But it does disprove the theory that everyone needs them all the time.
Now others will say that it is perfectly possible to do either low intensity exercise or short bursts of high intensity exercise without carbs; but that to sustain any kind of intense exertion beyond an hour or so (not maximum exertion, like HIIT requires, since no one can do that more than a few minutes), you must have carbohydrates. They have a lot of science to explain this and much of it is convincing. This may very well be true, at least for some people.
Again, the problem is that there are people who seem able to participate in all kinds of endurance exercise while in ketosis or even fasting. If you want to read about people who can do that, buy these guys’ book. They’re convinced you’ll actually be able to train and perform better and recover faster if you don’t eat carbohydrates.
So who’s right?
I’ve got no idea at all. Again, all I can tell you is what happened to me. And that’s where the death march comes in.
Our friends had invited us on a hike. Our impression was that it would be rather more like a stroll, so I was unprepared when we arrived at the first mountain. It was pretty much straight up. On my back I had our lunch (potted salmon) and some snacks (coconut caramel popcorn, apples, cheese, and peanut butter) and four bottles of water. We started climbing. About this time, The Roommate and I realized this wasn’t a stroll.
It wasn’t so much a trail we followed as a hollowed out gully made by water after a rain. Numerous places along the way required the use of all four limbs to get up. There was little level walking. Nearly two hours into it we took a break as it seemed one of our friends very much wanted to eat.
This was an excellent sugar vs fat burner test. The Roommate and I had eaten 95g of fat, 21g of protein, and 2g of carbohydrate that morning. I don’t know what our friends ate, but they tend to eat plenty of carbs so I would guess they were carb-ed up for this hike. At our stop, they ate sandwiches and fruit. The Roommate and I weren’t actually hungry, but we figured this must be lunch, so we ate our potted salmon, which was about 26g more of fat and 26g of protein.
Then I made my big mistake. I ate an apple.
I don’t eat much fruit, but I thought if there was ever a time I could burn off the sugar of an apple, this was the moment. Up until that moment I’d been feeling great. Plenty of energy. Able to run up the trail at points. Not hungry. But once I ate that apple, the next twenty minutes were much harder. I felt like I used to feel eating carbohydrates all the time. It was mostly just willpower that got me through.
(Of course that last picture is a little misleading. It looks straight at the tower, but we had to go back down the other side of the mountain we were standing on and go up the tower mountain from a lower spot than this photograph was taken from.)
Twenty minutes later, my body switched back to fat burning and all the strength returned in a sudden flood. I could jog up places again. We hiked, and often we climbed using hands and knees. When we reached the top we ran into this:
When we reached the top, our sugar-burners were ready for more sugar. The fat burners were happy to eat, but didn’t really have any feelings one way or another. We stopped in a tower for another snack, which for us was cheese and peanut butter (and a little caramel popcorn for The Roommate, who tolerates sugar better than I do). Our friends ate chips, popcorn, more fruit, crackers, sandwiches, and other carbohydrate-rich foods.
Then we had to climb back down.
The whole thing took nearly seven hours, with some breaks. It wasn’t maximum intensity, but it was strenuous over the long-term–strenuous enough to prohibit conversation other than a sentence here or there much of the way. It required endurance, and the fat burners–with nearly zero carbohydrates in their system–had no trouble keeping up. Before and during the climb I ate approximately 1,400 calories, yet did not feel hungry or weak.
So I also don’t buy that you can’t sustain effort for hours at a time without carbohydrates. At least not for me. All that apple did for me was interrupt the smoothness of the race, like a bad tire on a car at the Indy 500. It also begs a really important question:
Where did the Mongols keep their Power Bars when they invaded China?
Plato says he’s hungry
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