Lately I’ve been on kind of a diet and exercise kick trying to put on some weight and get more cut. It started with ‘ article on gaining muscle quickly. Then I saw Dream’s talk on proper exercise and nutrition which opened me up to a whole new world of ideas. I’ve since read Body by Science and there was a whole new world of information which I digested in a couple of days. I’m now reading Good Calories, Bad Calories, which Tim Ferriss considers to be the definitive work on nutrition, and it’s making a lot of sense to me. It’s really fascinating that the public’s general understanding of these two topics is essentially wrong in every possible way. In fact, if you do the exact opposite of what pretty much anyone out there tells you to do, you’ll be healthier and get better results.
So obviously since this is something that I’ve really engulfed myself in and including starting an all (grassfed) meat diet, people I know have started to take some interest, including a colleague of mine sending me an article in a NY Times blog which baffled me. I spent some time today writing an email in response:
When I saw the title of this article, I had really high hopes for it. Could this help fix all of the myths in current weight loss and exercise culture? Unfortunately, I was very disappointed. I barely even know where to start.
First of all, not all calories are created equal. While taking in less calories than you burn is a sure fire way to lose weight, the macronutrient that you get those calories from matter. Tim Ferriss gives a GREAT example of this in the scientific research in this post comparing Ancel Keys’ Great Starvation Study (Keys is the man who is basically single handedly responsible for this pervasive myth that saturated fat and cholesterol are bad while carbohydrates and sugars are good) with John Yudkin’s low-carb study. As you can see, the two groups on average ate nearly identical numbers of calories, yet one group starved to the point of insanity and breaking off their own fingers while the other self selected to eat 10 less calories on average.
Second, this sentence is, and I mean no disrespect in saying this, beyond idiotic: “It is well known physiologically that, while high-intensity exercise demands mostly carbohydrate calories (since carbohydrates can quickly reach the bloodstream and, from there, laboring muscles), low-intensity exercise prompts the body to burn at least some stored fat. All of the subjects ate three meals a day.” While low-intensity training may burn some fat stores in your body during the exercise, the number of calories burned during exercise is totally irrelevant, particularly given the number of calories that you’re burning in an exercise. One pound of fat has 3500 calories, and you just aren’t going to burn that many calories from exercise, or even anything close to that, so why are we measuring the fat that is burned during the exercise?
On the flip side of this discussion though, here’s what a low-intensity training does do; it stimulates low order slow twitch muscle fibers which require very small amounts of energy (ATP) to fire. There are a lot of these slow twitch fibers, and they recover very quickly, so no matter how long you pump your legs on that bike, you’re not going to get to the higher order fibers. This type of exercise tells your body that you are about to find food, and as a result makes you hungrier, because our biology is built for a world in which food is a scarce resource (2 million years as compared to 300 generations since agriculture). This is why people get hungrier as a result of “cardio.”
Assuming that people resist this urge to eat more, however, they are still not going to see the calorie burning effects. You see, your body likes homeostasis. It’s about survival. If your body notices an imbalance in the energy being taken in and the energy being burned, it will fix this by breaking down your most energy expensive tissue, your muscles. As of now the most difficult exercise you’re doing is riding a bike with low resistance for a half hour, and you’re only using a couple of your slower twitch fibers, so the body will break down the more energy expensive fast twitch fibers that are not being used. This will lower your basal metabolic rate, and now you need to cut your calorie content even more to lose the same amount of weight.
The solution to this is doing High-Intensity Training, which works out all of your muscle fibers to failure very infrequently. The idea behind this training that you put your body through a substantial trauma and then give it time to recover. Given enough time, your body will overcompensate in its recovery, thinking that your environment is more dangerous than your current musculature can handle, and the result is more muscle mass. The number of muscle fibers in any given muscle is fixed, but the size and strength of each of these fibers is variable. This means that your body will be able to do the same exercise using less muscle fibers, and as a result require less oxygen. These are the “aerobic” gains that people speak of. It’s not actually an increase in your lung and heart capacity, it’s a change in the musculature. Now, lung and heart capacity can increase, as they will grow proportionally to growth in your musculature, but “aerobic” gains are muscle specific. This is why someone who is a marathon runner will get out of breath very quickly if they try rowing a meaningful distance, and vice versa.
Increases in your musculature will also increase your basal metabolic rate, as well as a bunch of other great weight loss and health benefits. Your body stores glycogen in the muscles in case it has an emergency fight or flight situation that it needs to get out of. Low-intensity exercise will not tap into these reserves, which is why it will burn some fat during the workout, but high-intensity training will deplete the energy in these stores. As a result, when you eat new carbohydrates, they will be taken up by your muscles as opposed to your fat cells. Your muscles will also become more insulin sensitive, which is important because insulin is very bad for your tissue. Less insulin in your blood stream means less trauma to your veins. Cholesterol is the substance that your body uses to patch up this trauma in your veins and arteries, so lowering this trauma lowers your cholesterol levels. Cholesterol is not inherently bad for your body, it is actually a symptom of problems rather than a cause. You can find more color on this subject in Good Calories, Bad Calories. That’s pretty much the definitive book on nutrition and weight loss if you want to learn how to effectively diet, although I would argue that this is how everyone should eat.
I implore you to do your own research and correct your article. If you want to learn more about all of this, Body by Science is a great resource.