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So far we’ve done quite of bit of talking about diet including all the basic elements (quantity, quality, timing, water, protein, supplements, and tracking). There is plenty more to talk about diet wise, but at this point I think we know enough about that to get started talking about the other part of losing weight: Exercise.

I’ve never really been a “work out” kind of guy, sure I played some sports as a kid, and spent a few years in the Marines, but lifting weights just never seemed to be my bag. Until recently, I always thought that losing weight was purely a matter of calorie control “watching what you eat”, and maybe some cardio like running or aerobics if you wanted to hurry things along. As it turns out, I couldn’t have been more wrong.

The human body is amazing piece of machinery, and it’s extensively optimized for a pre-technological environment. When you start eating less food, your body doesn’t think “diet”, it thinks “*%&$! We’re going to starve!”. As a first reaction to this reduction in food supply it does several things:

1) Reduce energy expenditure by downshifting the metabolism

2) Hold on to energy storage (fat tissue) more tightly than normal

3) Start catabolizing muscle tissue (breaking it down)

We’ve already discussed items one and two a bit when we went over the mechanics of Leptin, so let’s talk about catabolism for a minute.

Muscle tissue is metabolically expensive, it takes quite a bit of energy to keep it fed and operating properly. No matter how out of shape you are, you have quite a bit of muscle tissue, or you wouldn’t be able to move. Now, since it’s so expensive, the body sees this as an easy place to economize when things get tight (like cutting off the movie channels when you’re trying to save on your bills). In fact, any muscle tissue that isn’t seen as “necessary” will get broken down very swiftly, which is why astronauts have so much trouble coming back to earth after spending a lot of time on the International Space Station. All that zero gravity really makes things easy for the muscles.

So you may be thinking to yourself, “fine, what do I care, I never wanted to be muscular anyways, I just want to be THIN!”. Well, the problem is that muscle burns up a lot of energy, when you lose it, your daily calorie requirements go down. This can cause people to plateau on their diet until they cut their energy intake more, losing more muscle creates a second plateau, leading to another cut, until finally the person doesn’t have enough willpower to make any more cuts, and either gets stuck, or reverts to their old habits. This is what causes the effect where many people gain back more weight than they initially lost when they stop dieting. Even worse, your overall metabolism will be slower than when you started!

So how do we avoid this unpleasant situation? We need to tell our body that keeping all that lean tissue is important. Unfortunately we can’t just pick up the phone or send a memo, we need to speak in a language the body understands. The body is a survival machine, so if breaking down the muscle tissue in your legs makes you a slow runner, and you spend a lot of time running away from saber tooth tigers, that would be a “bad thing” from a survival perspective. To compensate, the body tries not to break down any muscle tissue you’re using on a regular basis. There is a priority system as well, the steeper your calorie deficit, the more likely it is to break down muscle tissue to try and keep you alive.

To make things more complicated, there is a principle called “The specificity of training”, which means that different kinds of training will produce different kinds of effects. So for example, Marathon running, and 400m Sprints will not produce the same sort of results. Compare the skinny chicken legs of a marathon runner and the beefy quads of a sprinter, and this will be pretty obvious. So not only do we need to do some training, it has to be the right kind of training.

Cardiovascular exercise involves the lungs and heart because, from the bodies point of view, it’s low intensity over a long duration. Examples include running, aerobics, swimming, cross country skiing, etc. Cardio, as it’s often known, burns a large number of calories and creates a short term increase in basal metabolic rate. The adaptation effect of cardio is to increase VO2 max (basically your lung capacity), mitochondrial density (which helps you oxidize more energy), and provide for better control of lactic acid buildup (the burning feeling you get in your muscles when using them strenuously). Unfortunately, none of that does anything to let your body know that the muscle tissue is important. In fact, by creating a steeper calorie deficit, you’re actually making things worse!

Hypertrophy training is the answer. Hypertrophy is the reverse of catabolism, it’s the process of building muscle. If we train in such a way as tell the body that we need to build muscle, but at the same time create a calorie deficit the body doesn’t have anywhere else to turn for the extra energy except the reserves stored in your adipose tissue (fat).

All training, cardio included, is essentially the process of exerting your muscles against a load. In the case of running, the load is your bodyweight. (effectively a combination of your physical mass and the planet’s gravitational field) Exercise modalities can be crudely broken down into different types based on the number of times they’re repeated, or reps:

100+ Cardiovascular exercise
20-99 Endurance
14-20 Strength-Endurance
9-13 Sarcoplasmic hypertrophy
5-9 Sarcomere Hypertrophy
2-4 Strength
1 Power

We can quibble over the various ranges, and there is some overlap between them, but this is the basic idea. High rep activities, like swimming, are going to promote more endurance adaptations than hypertrophy, while lower rep activities like lifting weights will promote more hypertrophy adaptations, which are the kind we need to hang on to that expensive muscle tissue. Going extremely low rep is also counter-productive from a weight loss point of view, as it tends to focus more on strength and power gains, which are largely caused by increases in neural efficiency and rate coding, not muscular hypertrophy.

Over the next several articles I’m going to talk about how to set up a weight training program from scratch, and all the different variables including exercises, reps and sets, equipment, schedules, etc.

Tags: Exercise, Metabolism

This entry was posted on Monday, December 17th, 2007 at 2:59 pm and is filed under Fitness. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.