There is probably no other topic on this planet that people find more confusing – and frustrating – as body fat, or more specifically how to get rid of it.
In this article we discover the truth about fat blasting, metabolism, and calorie burning. In the process, we’ll find out just how you can optimize what you’re doing to get rid of unwanted stored fat faster.
The Law of Energy Balance
We all need a specific amount of energy in order to maintain ourselves and keep a healthy weight. If the amount of energy that we take in consistently exceeds that amount, the extra will be stored as body fat. If the amount of energy is consistently lower than the required level, body fat will be tapped into in order to make up the shortfall and we will lose weight. This is known as the law of energy balance.
The key variable in the law of energy balance is the amount of energy that we consume. And that is something that each of us has total control over. You are the master of what goes into your mouth, which gives you the power to control your energy balance.
You are also in control of energy expended. You can increase the amount of energy expended through exercise. However, exercise alone is not the best way to lose weight. Studies show that while regular, vigorous exercise can induce weight loss in a controlled experiment, it isn’t such a successful strategy among people in the real world. Too often we make up for the extra energy expended by eating more food. Often, too, we simply don’t do enough exercise.
Research also indicates that exercise by itself leads to more weight loss in men than it does in women. For the best chance at long term fat loss, we need to combine regular exercise with some smart changes to the way that we eat.
Your Daily Energy Use
The amount of energy that you use daily is the sum total of:
- Your metabolic rate
- The amount of energy in calories that you use in processing and digesting food
- The amount of energy you burn during physical activity
The word metabolism refers to all the chemical processes involved in converting food into energy. The rate at which we do this is as known as the resting metabolic rate (RMR).
Exercise to Burn Fat
Physical exercise is the most important component of daily energy expenditure. As well as burning calories, it will provide you with a whole host of health benefits. Both normal daily activity and ‘workouts’ are important in maximizing the contribution of physical activity to total daily energy expenditure. But it is more structured exercise that really revs up the calorie burn by increasing the demand for energy significantly both during the session and afterwards, when the body uses additional energy to recover.
Vigorous exercise, such as a spinning class, can increase your metabolic rate by six to ten times the resting rate. When you consider that a 130-pound woman burns roughly 60 calories an hour at rest, you can see what an impact a 49 minute run at nine-minute mile pace would have in total daily energy expenditure. The woman would burn an extra 450 calories, a 34% increase.
The great thing about exercise is what is known as the after burn effect or, more precisely ‘excess post-exercise oxygen consumption (EPOC). This describes the amount of oxygen used over and above baseline levels in getting the body back to normal after a workout. The even better news is that the after burn effect is almost totally filled from stored body fat!
The size of the after burn effect is determined by the type, duration and intensity of the exercise that you choose. Exercise at greater than 75% of maximum capacity has a significantly greater effect than lower intensity exercise. You will not get a great deal of EPOC from low intensity exercise, because you haven’t used up much glucose and it is the replenishment of glucose stores which is one of the most energy hungry processes.
However, we need to keep the EPOC effect in perspective. You won’t be able to burn off a bad diet with it. You will be able to burn between 50 and 200 calories following a typical high-intensity workout. For example, a study in Medicine and Science in Sport & Exercise found that 45 minutes of resistance training elevated the metabolism for two hours afterwards, resulting in an additional expenditure of 155 calories.
Eating to Beat Fat
Digesting and processing the food we eat actually requires calories. This phenomenon, the ‘thermic effect’ of food, accounts for around 10 per cent of total energy expenditure. While you can’t do much to increase this, you can decrease it by skipping meals or trying starvation diets, thereby depriving your body of its opportunity to get busy with food processing. Research shows that, for weight loss, grazing, or taking in your daily calories over a number of small meals rather than in just one or two large sittings, is more effective, because small meals are not accompanied by a dramatic insulin response that promotes the storage of food as fat.
The Best Fat Blasting Workouts
The often repeated advice about exercising moderately for 30 minutes on most days of the week is fine, if your goal is to improve your general health and reduce your risk of heart disease, but if you want to get aerobically fit, lose weight, keep it off and stave off the age-related declines in metabolism and muscle mass, it simply isn’t enough, either in amount or intensity.
The 30 minutes of moderate exercise prescription would burn approximately 200 calories. Studies, such as one from the US National Weight Control Registry, showed that successful weight-loss maintenance entailed burning twice as much as this, while research published in the Journal of the American Medical Association found that in a group of overweight women who embarked on a diet and exercise program, 40 minutes of exercise every day produced and maintained a 29-pound loss over 18 months, while lesser amounts did not succeed in keeping weight off.
In addition, studies are showing that while low-intensity exercise (like walking) is good, more intense activity has even greater benefits. According to exercise physiologist Gary O’Donovan, vigorous exercise is the most effective form that you can do . . .
Health, fitness and performance are all maximized by working harder, which isn’t to say that you won’t benefit from lighter exercise, just that you will benefit more if you work.
Research backs him up. A study in Medicine and Science in Sport & Exercise found that, in young women, high-intensity cycling compared to low-intensity cycling with an identical overall work output (so the low intensity group cycled for longer) resulted in significantly higher energy expenditure during the exercise itself and over the subsequent 24-hour period.
The Fat Burning Zone
Energy for exercise is produced through the metabolism of fats, carbohydrate and protein (the latter supplies just 5-10 per cent of energy needs during exercise). So, the ideal scenario, if you are aiming to lose body fat or control weight, is to enable as much of that energy as possible to come from fat stores.
Fat metabolism takes place in the mitochondria of muscle cells – the energy producing factories. But fats can be metabolized only when there is enough oxygen present. When you are putting just a small amount of effort into your workout, and aren’t breathless, there is plenty of oxygen available, so the energy comes mainly from fat.
The problem is that, at such low intensities, the total calorie expenditure is very low, and consequently, even if 90% of energy comes from fat, total energy expenditure is low.
As energy intensity increases so does total calorie expenditure. The body begins to rely more heavily on carbohydrate as an energy supply. But because the overall calorie expenditure is higher, the actual amount of fat burned is also higher. In addition, as you get fitter, you can work at a greater intensity while still burning lots of fat.
So, while low to moderate intensity exercise burns the greatest proportion of fat as a percentage of total energy expenditure, higher intensity exercise burns more calories overall and it is the total energy expenditure that counts.
The Bottom Line
Higher intensity exercise will not only give you greater health and fitness benefits, it will also take up less of your time – and it will allow you to burn fat faster and more efficiently. So, what is the best fat fighting form of exercise? It is the one that you most enjoy and will do most often. Whatever you choose make sure that it follows these criteria:
- It should use the large muscles of your body
- It should be sustained for 20-30 minutes
- It should make you sweaty and a little breathless
- It should be done regularly
- It should be weight bearing (like walking and running) rather than weight supported (like swimming or cycling)