All About Metabolism

Do you know anyone who seems to be able to eat as much crap as they like and yet is stick thin? Perhaps you know somebody else who only has to look at half a grape and instantly puts on half a stone! The reason for this descrepancy is that these two people have different metabolic rates.

Put simply, your metabolic rate is the rate at which your body burns calories. The higher the rate, the more calories you will burn. Obviously then, higher is better. Some people are naturally blessed with high metabolisms, others cursed with a low one. Some medical conditions such as an under-active thyroid can lower metabolism. However, you are not stuck with what you've got as there are many factors that influence it.

The first and foremost of these is your muscle. Muscle needs energy, fat does not. The more muscle you carry on your body, the more energy (in the form of food and drink) your body needs to sustain it. Your fat on the other hand can survive all by itself!

So, think for a moment what would happen if you were to go on some crash diet in which you lost a large amount of body weight in a short space of time. Take the example of your friend who lost 1 stone in 2 weeks on the Atkins diet that I mentioned in the last entry. We already know that most of that stone is lean body mass because unless he had a very large amount of fat to lose, probably no more than about 4 lbs of it was fat loss. So if that was the case, your friend has lost 10lbs of lean body mass, which in turn means that his metabolic rate has just dropped dramatically.

In real terms, on average, every pound of muscle requires around 50 calories a day to sustain itself. So if you lost 10lbs of muscle, your body would need 500 calories less per day than it did before! This is disastrous! So let's say that your friend is at first happy with his weight loss so he goes back to his eating habits before the diet but now his body doesn't need as many calories and 500 a day extra are being consumed!

1 pound of fat equates to 3500 calories. Eat 3500 calories too many and you gain a pound of fat. Eat 3500 calories less than your body needs (slowly!) and you lose a pound of fat. It's never that precise but you get the idea. So your Atkins buddy goes back to his old ways, and because he's now eating 500 calories a day more than his body needs, the weight starts creeping back on at a rate of around 1 pound a week (Oh, and this will be fat he's putting on, not lean body mass - that takes effort!). What does he do? Goes back to Atkins of course! He goes on another crash diet, loses another stone and reduces his metabolism further. You get the picture... This is called yo-yo dieting and it's a Bad Thing.

To keep the fat off on a permanent basis then, it becomes apparent that you must keep up your metabolism. A large part of your metabolism is based upon your lean body mass so you want to preserve what you have at all costs.

But there's more to say about metabolism. Your metabolism has a base rate that it works at all the time but it can also rise and dip over a period of weeks, days and even over the course of the day.

What makes metabolism drop?

A great way to make your metabolism drop is to reduce the number of calories you consume! The further your drop them, the more your metabolism will drop! How can tha be? How is anyone supposed to diet if reducing their calories just reduces their metabolism as well? This is probably the biggest problem with a 'diet-only' approach. First I'll explain why it happens.

Have you ever heard stories of people who have managed to survive for weeks without food? Humans have a strong survival instict thats built right in to them. The body can detect when it is being deprived of food. Thus, it tries to conserve precious energy by lowering the metabolism so that it doesn't need as much food. This is called the starvation response. There is usually a delay beween the calories dropping and the metabolism dropping. The higher the drop the shorter delay but this is the reason why even a modest diet can seem to plateau after a few weeks.

Another way to make the metabolism drop is to go without food for long periods of time. I don't mean weeks or days, I mean hours. Lets say you eat dinner at 7pm and you're the kind of person who tends to skip breakfast. You'll probably be hungry before lunch so you grab something at 11am the next day. Your body has gone 16 hours without food and that will trigger the starvation response. While your body is sleeping the metabolism will naturally drop anyway but after you wake up in the morning it will need some food to kick start it into action again. This is the reason why you are often less hungry in the morning if you skip breakfast!

So it seems as though all the things that are involved on a diet will actually cause the metabolism to drop which work against what the diet is trying to do! Exactly! This is why you'll often hear 'diets don't work'.

It's not all bad news. There are several ways to raise your metabolism.

First and foremost, any form of exercise will give your metabolism a big boost whilst the exercise is being performed. So, if you reduce your calories slightly, and exercise daily you should be able to offset the metabolism drop caused by the diet by the increase caused by the exercise.

Secondly, eating will raise your metabolism. Thats why its much better to spread your meals out throughout the day and eat 'little and often' than just eat 2 or 3 big meals.