Weight: 225.4 (-5.6)
Fat: 35.2% (-4.1%)
Meals: Not available
Exercise: Light Cardio (Treadmill 30:00 WL3 - 278 calories, 1.75 miles)
Pictures: Front/Side/Back

So after yesterday's depressing post on the success (or lack thereof) of diets, let's talk about exercise and how ineffective it is! First off, let's recognize that there are two different types of exercise: cardiovascular exercise, and strength training.

Cardiovascular exercise, also known as cardio or aerobic exercise, is exercise which primarily works the heart and lungs. Running, jogging, swimming, biking, stair climbing and rowing are all examples of different cardio exercises, but anything that gets you moving over a length of time can be considered cardio. The goal is to raise the heart rate through constant motion of big muscle groups. As the muscles are used, more oxygen is required from the lungs, which in turn is pumped out by the heart.

Strength training, weight lifting or resistance training involves the application some force to oppose the muscles. This force can come from lifting weights such as dumbbells, stretching elastic bands, or even working against the force of gravity. However it's done, working these muscles strenuously encourages them to grow in mass and size. Although the process of building muscles burns calories, many tout the extra benefits of muscles consuming more calories at rest than fat.

Now that we know the difference, which works best to help us burn fat? The current vogue seems to be strength training. The idea that muscles burn fat "even when you sleep" is a desirable quality for people looking to supercharge their workouts. There's only two problems with this. The first is that building muscle is slow. The reason for this is quite simple: muscles don't grow simply by working them. Muscle growth occurs during the recovery between workouts. Typically this takes one or more days of rest to occur. Any extra weight lifting will actually impair this recovery process, slowing muscle growth. The reason steroids are used by body builders is not because they make workouts more effective, but they allow this recovery to happen faster, allowing the user to get back into the gym and start the next recovery process sooner.

Even worse, the actual amount of calories a muscle burns at rest seems to be wildly exaggerated. I've seen figures of 50 to even 100 calories burned per day for each pound of muscle you have. Wouldn't it be great to put on 10 pounds of muscle and burn an extra 1000 calories, or 7 pounds of fat a week without even working out? The problem is, after doing some research it seems that those numbers aren't based in fact at all. There a number of studies that suggest the number is far smaller, usually 5 or 6 calories. Granted, 50 calories a day, or 350 calories a week for free ain't too bad. But instead of dropping 2 pounds a week, you'll need 10 weeks or 2.5 months to drop a single pound.

So we come back to cardio, and once again the message is not quite as rosy as we might hope. On one hand, we have articles like Does Exercise Really Make Us Thinner? and Why Exercise Won't Make You Thin which suggests that burning more calories just leads us to eating more calories, creating an equilibrium. And it's true, cardio will increase your appetite and if you don't watch your calorie intake you'll end up doing nothing. Burning 500 calories on the treadmill and then drinking a smoothie with 800 calories is going to help you gain weight, not lose it.

We also make a big deal about the effects of metabolism and how cardio will help you boost it. Sadly there isn't much evidence that cardio will increase your metabolism for any significant length of time after your workout is complete. There may be some benefits, but I was unable to locate any good studies that suggest it is significant or meaningful.

Going back to the topic of this blog post, if cardio and strength training aren't very effective in losing weight, why exercise? There are several reasons:

  1. Atrophy - If you don't work your muscles you're going to lose them along with your fat. A calorie deficit doesn't mean you're only going to burn fat!
  2. Disease - Exercise has been proven to reduce your chances of developing a number of diseases, heart disease and diabetes being the most obvious, but not the only ones
  3. Endurance - The more you work out the easier it becomes. If you enjoy sports you will have an easier time engaging in them. Going to the beach, or even walking around an amusement park is easier when you're in shape. Sex is more enjoyable when you have stamina and strength
  4. Depression - If you're overweight chances are you're not too happy about it. Clinical depression is a serious issue and while exercise won't eliminate it, it can help reduce it

I'm sure there's more, but most significant in my opinion is found in the conclusion of study published in American Psychology that I posted about yesterday:

This confound is particularly significant because correlational studies consistently find that individuals who reported the most exercise also had the best weight loss maintenance

Exercise has also been shown to improve the maintenance of weight loss in two meta-analyses of controlled trials in which participants were randomly assigned to diet and exercise or just to diet

Finally, as noted earlier, exercise may very well be the potent factor leading to sustained weight loss, particularly among participants in the National Weight Control Registry

In short, diet or exercise alone are not very good at achieving weight loss. But together, they're much more effective. How effective that is depends on you and how much you're willing to change to achieve your goals.

P.S. Everyone say hello to Moxie. She's the smaller furry one in the back picture. No doubt she was wondering why I was standing in front of this curtain staring at it.