As I Understand It: Basal Metabolic Rate and Weight Loss

Note: I am not a doctor or a nutritionist. What I am, however, is a currently fat person who has been dieting on and off for forty-seven years. Lately I’ve become frustrated with my futile attempts to lose weight and I’ve gone on a quest to gather as much information as I can about the mechanics of weight gain and loss.

People who have never gained a significant amount of weight have no idea how it can sneak up on you. Thin people don’t see how you can’t feel every extra ounce and go into furious activity to get rid of it. If you had only done that when you were one pound overweight, they think, the other pounds wouldn’t have followed.

But gaining weight isn’t like that. For one thing, the fat doesn’t show up immediately after eating the extra calories. Nor does it disappear as soon as you cut your calories. It’s not a mere addition or subtraction scenario. Calories go through a complicated process on their way to becoming whatever they’re going to be. And the one thing that makes it somewhat unpredictable is something known as the basal metabolic rate (BMR).

BMR is the rate at which your body burns up calories when you’re not doing anything. In an ideal (and just) world, everyone would have the same BMR. If we did, we’d all burn calories at the same rate no matter what age we are or body shape or size we have. If everyone’s BMR was suddenly the same (say somewhere in the middle) then skinny people would gain weight and fat people would lose weight. (BMR calculator here.)

That’s one reason why I get disgusted when weight loss “experts” state that gaining weight is merely a combination of too much food and too little exercise. They’re only partly right. It also depends on things like body type, age, sex, amount of muscle and fat on your body, and yes, basal metabolic rate.

Many, if not most, experts will tell you that your metabolism has little to do with weight gain. That may be true when you’re measuring like individuals (same age, same body composition). But tell that to a person who never had trouble maintaining her weight until she went through menopause. Or who eats and exercises exactly the same as her friend who has a smaller body type.

One thing they don’t usually tell you is that because muscle burns off more calories than fat does, you’re better off to do anaerobic than aerobic exercises. Aerobic exercises are important for improving cardiovascular fitness, but they’re not going to help that much to help you lose weight over the long haul. You can have great lungs and a healthy heartbeat and still be fat. Which is good news for fat people. But not so good for people who have been relying on the treadmill to help them to drop pounds.

Don’t get me wrong, I’m not saying that it isn’t beneficial to move. For one thing, cardiovascular exercise makes your blood flow more efficiently throughout your body. But people who insist that you’re not going to see any benefits unless you exercise a half hour, or even an hour, every day are just setting the bar too high and making people feel like it’s pointless to exercise at all if they can’t meet that standard.

One thing that doesn’t raise the rate at which your body burns calories is eating less calories. In fact, when you do that, your body automatically lowers your BMR in order to save energy. Your calorie needs are only 1.2 times your BMR, so you’d have to undercut your calories well below your basic physical needs in order to see any significant weight loss. And guess what? That’s just not good for your body!

I know a young woman who lost 50 pounds in a half year by eating only 800-900 calories a day. Her only exercise was a lot of walking. She lost the weight but she stopped having a period naturally for several years afterward. (She had to take birth control pills in order to get her body to approximate having a period.) And she only did it for a few months. What happens to women who do it repeatedly or for a longer period of time?

Dieting works the same way addiction does, except that it takes less, not more, of the substance (in this case calories) to get the same result. So ultimately dieting is self-defeating behavior. Eat low-calorie, low-fat, low carb diets if you want to, but none of them stay effective forever. That’s why dieters go through so many diets. There is no one diet that is guaranteed to have results over the long haul. You can go on a starvation diet and your BMR will just keep going down until your body stops metabolizing food at all (and before that it metabolizes your own body until you’ve damaged it beyond repair).

The bottom line:

Don’t over-diet or you’ll lower your basal metabolic rate and have to eat even less calories to get the same result. (Over-dieting is my term for taking in too few calories or completely cutting out certain foods that are essential for your body to operate at peak capacity.)

Do exercise, but don’t feel that you have to meet someone else’s unrealistic goals (for you)— and make sure you emphasize building muscle mass.

If you find yourself yo-yoing (i.e., gaining and losing, gaining and losing in a vicious cycle), stop what you’re doing and find a sensible diet and exercise program that you can live with over the long haul.

Recognize that the heavier you are, the more calories you burn, so exercise is definitely not pointless.

Take into account your age, body type and composition, sex and medical conditions (or medications) that may slow down your metabolism. If you have any of these markers, exercise, not diet, is the key.

Be proactive: do your own research. There’s plenty of information out there, but be careful of websites that are just trying to sell you something.

It’s always a good idea to get a medical check-up, including a blood work-up, as soon as possible when you are planning to start an exercise and food modification program. Get your doctor to take you seriously. I can’t tell you how many doctors I’ve gone to who have completely ignored the fact that I’m fifty pounds overweight. Check with your health insurance to see if they cover visits to a nutritionist or memberships to a gym.