Understanding the Science Behind Weight Loss

Posted by – January 31, 2011

Losing weight is a simple endeavor in essence. Eat less and exercise more, and you’ll end up weighing less. But in practice it’s not so simple. If you’re overweight and you struggle to lose excess fat, most likely it’s because you find yourself craving food even when you’re not physically hungry, and that craving is hard to overcome.

Later on in this series of articles we’ll be looking at ways of reducing that craving from impossible-to-control levels to more manageable levels that you can successfully handle. But before we get to that, let’s take a look at the science of weight loss. Why do we put on weight, and how can we lose it? Once you have a firm understanding of the relationship between food, hunger, exercise and craving, you’ll be able to make good decisions about how to formulate your own weight loss strategy, based on sound science.

If science isn’t your bag, this article may seem a little complex. Don’t worry; the main take-home points are summarized as bullet points, and if you even skim through this article a few times, you’ll get the general gist.

Metabolism; How Your Body Uses Food

Your body is a very intricate and specialized sort of machine. Many of us believe that there is far more to a human being that this mere physical machine, but there’s no doubt that on one level, our brains and bodies operate according to known scientific laws, just like a car or a steam engine but a lot more complex. As a human being you need to move yourself around and to physically lift things and move them from one place to another; you also need to use your brain to think and your heart needs to pump blood around your body to keep everything supplied with fresh nutrients. All of this requires energy (in fact movement IS energy), and this energy comes from two sources. And those two sources are …. food and oxygen.

Although we think of food as our energy source, in fact food is useless without the gaseous chemical called oxygen that makes up one-fifth of the air we inhale. Your body takes this oxygen in via your lungs and reacts it with food to create powerful chemicals that are used directly to generate internal and external motion.

In this respect, your body is similar to a car, which takes gasoline and reacts it with oxygen from the air to produce the physical force that turns the wheels. Just like a car, much of the energy that’s created ends up being emitted in the form of heat rather than movement; although warm-blooded creatures such as ourselves have come to require a certain amount of heat to operate, in fact the production of at least some heat is an inevitable side-effect of living, moving, thinking and being generally active.

This production of heat and utilization of food energy happens even when you are sitting still. It happens as a result of the complicated thought processes that take place in your brain, as a result of your heart continually pumping blood, and as a result of all the other processes that take place in your body even while you are sleeping. This general ongoing utilization of energy is known as metabolism, and the rate at which your body uses energy (or in other words, turns food into heat and movement) is known as your metabolic rate.

How to Raise Your Metabolic Rate

It’s possible to raise your metabolic rate so that you use more energy even while resting, and so that you use more energy when going about your daily tasks. Although some substances, such as caffeine in coffee and tea, may raise your metabolic rate modestly, the healthy and safe way to raise your metabolic rate is by doing the right type of exercise, and we’ll look at this in more detail in a later post. The fact that exercise can raise your metabolic rate is one of the reasons why exercise has effects that last far beyond the time when you are actually exercising, and it’s one of the reasons why calculations based around how many calories a particular bout of exercise “burns” typically lead to a misleadingly-pessimistic view of how much weight you can lose through exercise.

You can already see that the car analogy breaks down rapidly. In fact, whereas a car literally burns the gasoline it uses in a series of tiny explosions that take place inside the engine’s pistons, a human being reacts food with oxygen in an extremely elaborate and fortunately quieter and more efficient manner. A car’s “metabolic rate” is largely fixed; you can’t train your car to become leaner and meaner by driving it fast! And unlike a car, the human body will store excess energy — energy that it doesn’t currently require — as fat.

Let’s take a look at what we’ve discussed so far.

  • The body chemically reacts food with oxygen from the air to create energy.
  • Some of this energy takes the form of movement, both internal and external; some of it takes the form of heat.
  • The conversion of food and oxygen into energy is known as metabolism.
  • The rate at which your body uses energy is known as your metabolic rate.
  • Excess energy is stored as fat.

High Metabolic Rate vs. Low Metabolic Rate

Now here’s where things get really interesting, from a weight-loss perspective. As you’ll soon start to see, it’s possible to tweak your internal settings in such a way that you not only lose weight but experience many other wonderful benefits too.

Let’s think a little about this business of metabolism. Clearly we don’t use the same amount of energy all the time. When you’re running about from place to place, lifting things and “thinking on your feet”, you tend to use a lot of energy.

When you’re asleep or watching TV, you use comparatively little energy.

To put this another way, when you’re moving around a lot your metabolic rate is high. When you’re asleep or slumped on the couch in front of the TV, your metabolic rate is low. What’s interesting about this is, people vary immensely in the degree to which they can switch their metabolism from a low state to a high one. People who habitually exercise a lot or are naturally active tend not only have a high average metabolic rate, but their metabolic rate tends to be higher than average even when they’re resting.

Your resting metabolic rate is known as your basal metabolic rate, and clearly if you want to lose weight, it’s good to have a high basal metabolic rate. Then you can lose weight even while you’re sitting still! Of course, there are some medical conditions and some drugs that raise a person’s basal metabolic rate; this isn’t healthy at all. People who have high basal metabolic rates for unhealthy reasons tend to be thin, pale and nervous, and prone to health problems. Trust me, you don’t want to follow in their footsteps.

People who have high basal metabolic rates for the right reasons tend to kind of radiate health and vigor. Even when they’re sitting still they are likely to appear happy and focused; when they are called upon to perform some physical or mental activity, they do so readily and easily. They tend not to get cold easily, because their bodies naturally generate heat even when they are still. Yet they generally don’t overheat easily either, since their bodies are adapted to movement and they are not encumbered with unnecessary fat. It is as if their metabolic rate is not only naturally high on average, but easily switches gear to become higher still when necessary. Since they use lots of energy, such people tend to be slim.

What about the opposite, people who have a low metabolic rate? Having a low basal metabolic rate tends to go hand-in-hand with finding it difficult to raise your metabolic rate when you need to, to complete some physical or mental task (even thoughts require energy!). This means that a “slow” metabolism often entails feeling tired or lethargic, having little energy or desire for exercise, and finding it difficult to complete even the tasks you need to complete. If your metabolic rate is low, you are likely to be overweight, since it is all too easy to consume more calories than you need.

The problem is made worse by the fact that food can become a way of alleviating the boredom and misery of a slow metabolism. You don’t have the energy you need to do the things you’d like to do in life; you put on weight and the weight physically and psychologically slows you down even further; then you turn to food as a consolation. Not everyone who is overweight also has a slow metabolism, but my guess is that the vast majority of those of us who have weight problems could benefit greatly by raising their metabolic rate. Indeed, who couldn’t use more energy?

The Magic of Appetite Suppression; Why Some People Can Easily Stick to a Healthy Diet

As if all of these downsides weren’t enough, there’s another key difference between low- and high-metabolism people, and understanding this difference is key to successful weight loss in my view. The fact is that when you eat the right kinds of foods and take the right kind of exercise, not only does your body adapt in such a way that makes it easy to utilize energy when you need to, but it also adapts in such a way that your appetite tends to be suppressed.

If your body was managed by a committee, it’s as if the committee is having meetings at which the chairman or woman bangs her fist on the table and shouts “It’s really difficult to utilize energy when we’re wrapped in fat! Sure we need plenty of food for our energy needs, but we’re getting too much as it is, and the excess fat is nothing other than a ball and chain around our ankles! We must make the body consume less food, now that we feel like moving around more.” The committee duly takes note, and decides to turn down the dial labeled “appetite”, so that you feel less like eating.

In my own experience, it’s this appetite-suppressing effect of a healthy diet and modest amounts of the right kind of exercise that really makes the difference between feeling the need to eat chocolate bars all day and genuinely feeling like you’d rather eat some fruit or go and do something other than eating altogether.

High Metabolism vs. Low Metabolism

Let’s summarize these key differences between high- and low-metabolism people:

Low Metabolism

  • Tends to be lethargic
  • Puts on weight easily
  • May get cold easily when resting
  • May crave food
  • May tend to overeat

Healthy High Metabolism

  • Has plenty of mental and physical energy
  • Easily maintains a healthy weight
  • Doesn’t easily get too hot or too cold
  • Has a stable, healthy appetite

Being stuck in a slow metabolism rut is a bad way to spend your life; but if that’s the place you’re in, the good news is you aren’t stuck as much as you think. You can raise your metabolic rate, and we’ll be discussing the details of how you can do this in later articles.

In a nutshell, it’s a question of doing the right kinds of exercise and eating the right kinds of food. Exercises that naturally raise your metabolic rate will cause your body to gear its resources away from storing fat and towards supplying you with the energy you need not only to continue exercising as part of your lifestyle, but more importantly to live your life as a whole. Yet you can’t only exercise, because your body needs the right kind of fuel if you want it to function more efficiently; that’s why we’ll also be taking a look at what kinds of foods will help you to lose weight. The answer might surprise you.

So if you want to lose excess weight successfully, raising your metabolic rate in a healthy way is the way to go. At heart, losing weight simply consists of using more energy than you consume, by eating less and exercising more. But you can make losing weight a lot easier for yourself if you raise your metabolic rate in a healthy way; you can do this by taking modest amounts of the right type of exercise while eating the right kind of diet. Losing weight and raising your metabolic rate will have all kinds of great effects besides weight loss; you’ll feel better and you’ll have more energy for doing the things that you want to do.

If you like the sound of this but you’ve never managed to make this work before — don’t worry; you’ve come to the right place. This series of articles is designed to help you gently adapt your diet and work out a way of getting exercise as painlessly as possible, in a way that suits you, your interests and your temperament.

Next: Pick Your Battles For Effective Use of Willpower

1 Comment on Understanding the Science Behind Weight Loss

  1. Priyanka Singh says:

    Brilliantly written and extremely helpful! Thank you.

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