How do I burn calories?

Your body burns off calories while undertaking several different types of activity. Some are easier to influence than others. So, for the purposes of this web site, we will split those which can be more easily affected into three groups:

•    Basal metabolic rate (BMR)

•    Normal daily activity

•    Specific additional energy burning activity

Understanding these different ways of burning calories is important. It will help you to make decisions about how to change your current lifestyle to meet your future ideal lifestyle.

In this section of the web site we will take you through the steps of estimating, as accurately as possible, your total daily calorie allowance for maintaining your current weight. Once you have that information you can then make better decisions about your future plan of action regarding calorie intake.

The figures in the graph above are for illustration only. But they do show that the BMR is typically the largest element of your daily calorie expenditure, often between 60% and 70% of your total.

You can have a significant positive influence on your BMR. The contributions made by normal daily activity and by additional exercise are also within your control from the outset. You can follow those links to look at each of these in more detail.

What is my Basal Metabolic Rate?

Your basal metabolic rate (BMR) is the rate at which your body burns energy (measured in kcals or calories) when at complete rest.

Even if you were asleep all day your brain would consume a large amount of energy as would your other organs and body tissue in keeping your heart pumping and your lungs breathing, maintaining your temperature, carrying out the enormous number of chemical interactions, ongoing body repairs and so on. People with larger bodies have to work harder just to keep operating smoothly so burn more calories than smaller people.

Muscle in the body consumes much more energy than fat. So people with a lot of muscle will have higher BMRs compared to those with more body fat. Since men tend to have more muscle than women they are allowed, on average, a higher calorie intake than a woman with the same body weight.

Everyone has their own BMR and it varies with a number of factors including sex, weight, body composition, age and your genetic make up. Your BMR can be estimated using some straightforward and well-established methods.

What can I do to change my basal metabolic rate?

Some factors are outside your control. For example, some people are genetically programmed to have higher rates than others; these are often people who can’t sit still and never seem to put on weight.
...your calorie intake allowance will also reduce as your slim down

Your BMR will also decrease as you get older, typically by around 2% per decade after your 20’s.

But you can increase your BMR through diet and exercise. By doing so you will begin to burn more calories naturally, even when resting and sleeping.

Caution - if you embark on an overly restrictive calorie reduction regime then you may actually cause your body to automatically adjust your BMR downwards! This will mean your body burns less calories in an effort to preserve energy during what it perceives to be “lean” times. This will almost certainly create the opposite effect that you intended.

Probably the best way to naturally increase your BMR is to replace body fat with muscle. As muscle burns more energy than fat your overall calorie expenditure will increase. For this reason you will find weight control and weight loss is more effective if a reduction in calorie intake is combined with an increase in physical activity.

Using overall body weight to calculate BMR gives a reasonable estimate for the majority of people. We each have differing body compositions such as the amount of lean body tissue – muscle, organs and the like – compared to body fat in the form of essential fat and storage fat. Those who are at either end of the body composition scale - particularly well muscled or particularly fat – will not get as accurate a reading as more mainstream body types. Heavily muscled individuals will receive a calculation that underestimates their calorie expenditure while very fat individuals will be given an artificially high allowance figure.

If you know, or are planning to find out, what your body composition is then you can use a more accurate formula to estimate your BMR. Separate formulae for males and females are not needed as the gender based difference in lean muscle mass is taken care of in the calculation:

And remember, your BMR will also change as your body changes. If you are reducing your weight, and all other things are equal, then your BMR will reduce with your weight. That means your calorie intake allowance will also reduce as your slim down. This reduction can be effectively offset through exercise which, as well as expending immediate energy, will build more muscle mass and raise your background burn rates.