Editor's Note:  This is another terrific article from Christian Finn!  In this article, you'll discover the most effective way to change your body composition so that you have more muscle and less fat.  As usual, Finn makes a suggestion on how to change your body composition that is incredibly simple and easy to follow.

One of the most important things you can do to change your body composition — the amount of fat and muscle you have — is to alter your energy intake.

If you want to lose weight, you need to burn more calories than you take in. To gain weight, you need to consume more calories than you burn.

The problem comes when deciding exactly how many calories you need in the first place. There are many different methods to help you do this. They range from simple formulas, such as multiplying your bodyweight by a fixed number, to more complicated equations that take into account your height, weight, age, resting metabolic rate and so forth.

Which is the best one to use?

Personally, I’m a big fan of keeping things as simple as possible. The approach I recommend (and the one I use myself) is to multiply your bodyweight by a fixed number that varies slightly depending on a few factors, such as your goal (whether you want to lose or gain weight), how often you’re exercising, and your current rate of progress.

However, I've had e-mails from people who question whether this method is particularly effective.

“When calculating the calories required for losing weight,” wrote one reader, “I have always thought that multiplying by total bodyweight seems strange since somebody with more fat will burn fewer calories than someone at the same weight but with more muscle.”

This is a good point. So, I thought it would be a good idea to explain a little more about why I recommend this simple approach over what might appear to be more complex and accurate methods.

It’s true that the amount of muscle you have does have an influence on your metabolic rate, though the impact isn't as great as you might think (see What They Told You About Muscle and Metabolism is Wrong for more information). However, fat has a metabolic rate too.

Contrary to popular belief, fat is not simply a "dead" tissue. In fact, some researchers now think of fat as an endocrine gland – an “organ” that responds to signals from hormones and the central nervous system, as well as secreting a number of bioactive peptides, such as leptin and interleukin-6 [1].

According to some estimates, fat has a daily metabolic rate of two calories per pound per day, with muscle clocking in at just six calories per pound [3].

To be completely accurate, a formula would need to take into account total fat stores (the location of those fat stores, whether visceral or subcutaneous, would also have an influence), energy flux, water intake, the relative proportion of protein and carbohydrate in your diet, the dominant type of fat in your diet, the type of exercise you do, and probably a whole bunch of other things that I haven't thought of.

Most formulas also ignore the fact that prolonged dieting lowers your metabolic rate, thus reducing the number of calories your body burns every day.

However, the extent to which this happens varies widely from person to person. For example, a study of Pima Indians lasting several years shows large differences in daily energy expenditure — even in subjects who lost the same amount of weight [4].

In one Indian who lost around 20 pounds in weight, the number of calories burned each day dropped by 400 calories. However, in another subject who lost the same 20 pounds, daily energy expenditure did not change at all.

This means that the accuracy of any formula will diminish over time. Most formulas tend to overestimate the calorie needs of people who have lost weight — in some cases by over 20%.

Weight loss is a highly unpredictable process. No study has shown that if you deprive people of the same number of calories, they will all lose the same amount of weight.

And what about people who want to gain weight?

Again, there are individual differences from person to person that make it very difficult to predict exactly how many calories you’ll need.

A good example comes from a Mayo Clinic study, where researchers found large variations in weight gain, even in subjects fed the same number of calories [2].

For eight weeks, participants were fed an extra 1000 calories (equivalent to two Big Mac hamburgers) daily. As you can imagine, this led to a gain in weight. In fact, the 16 volunteers gained an average of 10 pounds during the two-month study.

However, weight gain varied from two pounds to almost 16 pounds. The researchers found that the key factor in predicting fat gain was the change in calories burned during the normal activities of daily living — such as fidgeting, moving around, or changing posture. They called this NEAT (short for non-exercise activity thermogenesis).

Those with the greatest increase in NEAT (the most was 692 calories per day) gained the least amount of fat.

So, any formula that doesn’t attempt to take NEAT into account (and I haven’t seen any that claim to) won’t give you an accurate picture of your true calorie requirements.

Any formula, whether it's simple or complex, gives you a starting point. Then, you monitor your progress, and decide whether you need to change your training and nutrition plan based on the results you're getting.

In other words, your results should dictate the strategy.

Let's say that you set a goal of losing one pound of fat per week. As one of the strategies you use to reach that goal, you follow a diet that provides 12 calories per pound of bodyweight.

If, after a week, you haven't lost any fat (assuming that you've followed your exercise program to the letter), you can try dropping down to 11 calories per pound of bodyweight. Then, you continue to make slight adjustments to your diet and exercise program depending on the results you get.

This “results-based” approach is useful in other areas besides planning your diet and exercise program.

Last year, for example, I learned to fly a helicopter. Despite the best efforts of my long-suffering instructor, Captain Joe Moore, I took forever to learn how to land the thing. This was because I kept insisting on maintaining a fixed speed and rate of descent, even though I was obviously going to miss the landing spot completely.

It wasn’t until I learned to make small, continuous adjustments to my height and speed — depending on where I was in relation to my goal — that I was finally able to land the helicopter in the right place.

I’ve known people stick with the same diet and exercise program for months and months, despite the fact it was delivering little or nothing in the way of results.

If what you’re doing now hasn’t worked for the last four weeks, four months — or even four years, it’s probably not going to start working tomorrow. You need to try something different.

"There exists a virtually unlimited number of exercise and nutritional strategies you can experiment with if your initial plan doesn't produce the results you want," writes Tom Venuto in his e-book Burn the Fat Feed the Muscle.

"Don't be too dogmatic or rigid in your approach. Be flexible. It's good to have a plan, but don't get married to your plan. The more options you have at your disposal, the greater your chances will be for success. Leave yourself room to improvise."

Tom covers this subject in a lot more depth in chapter four of Burn the Fat Feed the Muscle.

Ultimately, it doesn't really matter if you use a simple formula (see How Many Calories Do You Need to Lose Weight? or How to Gain Weight Without Getting Fat in the Members-Only Area) or a more complicated method to set your starting point. What's most important is that you avoid continuing with a diet and exercise program that isn't delivering the results you want.

Although you need to stay committed to your goal if you ever want to reach it, you'll also need to remain flexible in the approach you use to get there.

Read other articles by Christian Finn

About the Author

Christian Finn is a Certified Personal Trainer and holds a masters degree with distinction in exercise science. He's lectured at a number of universities and private training organizations around the United Kingdom on fitness training, weight loss and the effective use of nutritional supplements. He writes extensively on the subject and his articles have been published in numerous magazines, leading industry journals and websites worldwide, including Men's Health, Men's Health Muscle, Fit Pro (April/May 2001), CAM magazine (February 2003), Image (January 1997), Zest (March 2004), and Body Life magazine (March/April 1997). He was also featured in the July 2004 issue of Muscle & Fitness (UK edition). His website, TheFactsAboutFitness.com, is dedicated to providing its members up-to-date, unbiased information and research on the world of fitness.

References

1. Kershaw, E. E., & Flier, J.S. (2004). Adipose tissue as an endocrine organ. Journal of Clinical Endocrinology and Metabolism, 89, 2548-2556
2. Levine, J.A., Eberhardt, N.L., & Jensen, M.D. (1999). Role of nonexercise activity thermogenesis in resistance to fat gain in humans. Science, 8, 212-214
3. Wang, Z., Heshka, S., Zhang, K., Boozer, C.N., & Heymsfield, S.B. (2001). Resting energy expenditure: systematic organization and critique of prediction methods. Obesity Research, 9, 331-336
4. Weyer, C., Pratley, R.E., Salbe, A.D., Bogardus, C., Ravussin, E., & Tataranni, P.A. (2000). Energy expenditure, fat oxidation, and body weight regulation: a study of metabolic adaptation to long-term weight change. Journal of Clinical Endocrinology and Metabolism, 85, 1087-1094