We all want to burn more fat for weight loss, body
shaping, health and wellbeing or for sporting purposes. Trim that butt, waste
that cellulite, smooth those love handles, bust that belly; it’s all part of
the trim and slim exercise and diet activity many of us indulge in.
In this article you will see exactly how fat burning
works and how to get the best out of your exercise program. Also, I'll outline
two weights circuit programs I developed to help you burn fat and lose weight
-- one for beginners and one for fitter trainers.
The Basics of Fat Burning
Energy in, energy out. The body normally burns a mix of carbohydrate,
as glucose, and fat for fuel. How much of either depends on your physical
activity and if, or what you have eaten recently. When you use more energy than
you take in from food and drink, the body burns stored fat and carbohydrates, and
then even protein, to fuel your everyday activities even if you are not
exercising
That’s what happens when people starve of course; the
body starts to eat itself. Depending on your family history -- your genetics --
and the way you eat and exercise to create this energy deficit, your body may
decide to get conservative and drop your metabolic rate to try to hold onto
body weight. Some of us seem to have inherited this tendency more than others,
the origins of which may be in the early periods of human evolution where
'feast or famine' was more or less the norm.
Glucose, fat and protein. Even so, starvation always works eventually and
the body starts to break down its own tissue for fuel. Stored carbohydrate
called glycogen is quickly used up, then goes the fat stored under the skin and
around the internal organs. Protein in muscle is then broken down to create
glucose to keep the brain working and you conscious.
Fat and glucose are the body’s two main energy
sources. Fat you know well, glucose comes mainly from carbohydrate foods like
rice and bread and potatoes and protein is supplied mainly by meat and beans
and dairy products. The amino acid building blocks of protein foods can be
converted to glucose in emergencies. Your body always burns a mix of fat and
glucose except at very high intensities, and the ratio of the fat and glucose
in 'the burn' varies with intensity and time of exercise.
Fat burning zone. You
may have noticed that some bikes and treadmills at the gym have a setting that
says “fat burning zone”, which implies a setting for intensity or speed. The
reason for this is that the body burns a greater percentage of fat at a slow
pace (or after about 90 minutes of exercise). The fat burning zone, a low
intensity speed zone is mainly a gimmick, and here is the reason.
Even though you burn more fat going slowly, you
still burn some fat at much faster speeds or intensity. It all
boils down to how much energy you expend in totality. For example, if you
compare exercising at a slow rate that burns 60 percent fat and 40 percent
glucose and a higher intensity or duration that burns only 30 percent fat and
70 percent glucose, you may still burn more fat at the higher intensity.
A typical example. Exercise
(1) is the slower 60/40 mix and exercise (2) is the faster, 30/70 mix of fat
and glucose fuel.
1.
Walking on a treadmill for 30 minutes --
180 calories used -- 108 calories of fat burned
2.
Running on a treadmill for 30 minutes --
400 calories used -- 120 calories of fat burned
You can see from this example that the bottom line
really is how much energy you expend -- and that is the ultimate fat burning
measure. The theoretical fat burning zone is mostly a convenient myth.
Weight Training Does it Better -- Or Does It?
Muscle burns more fat. Weight training is increasingly recommended as a
fat-busting tool because some experts say extra muscle burns more energy than
body fat at rest, so if you develop more muscle and have a higher muscle to fat
ratio than before, you must burn extra energy and more stored fat as a result.
This is true and has been shown in metabolic studies. However, the differences
are not that dramatic; perhaps less than a few tens of calories per day for
each pound of muscle increased, for most people.
Does that mean you shouldn’t worry about weight
training? Certainly not, because weight training has many other benefits for
health and performance, not the least of which is extra muscle. It’s just that
this advantage has been somewhat overstated and we need to get this fat burning
thing right in order to develop the best weight loss and performance programs.
Getting the afterburn. Okay, so extra muscle does not provide that much
advantage, but what about the afterburn? The 'afterburn', or the amount of
energy you use after you stopexercising, has been promoted as an
important slimming idea. If you can get afterburn, which is really another way
of saying your metabolism increases for several hours or longer after a
particular exercise, then that’s a bonus because you burn fat during the
exercise and after you cease as well. Will the fun ever stop!
However, this idea has recently been reconsidered as
well. An article in the Journal of Sports Science reported
that despite some promising early studies of this effect, the idea has not
proven to be as useful as first thought.
Exercise scientists call this afterburn effect EPOC,
which stands for Excess Post-exercise Oxygen Consumption. The authors of that
study say that the high intensities required -- greater than about 75 percent
of maximum heart rate -- are probably beyond what most people wanting to lose
weight can cope with in sustained exercise. So the afterburn advantage from
lifting weights or running fast is there, but you need to be able to sustain
that intensity, which means a lot of hard work. No secrets there, I'm sure.
We also need to consider how fuel is used
preferentially according to how your body stores are maintained. After you do a
vigorous or long workout, your blood and muscle glucose will be much lower than
before you started. Low glucose stores signal the body to burn fat
preferentially. So after hard exercise that uses a lot of
glucose, the body switches to burning fat. That's why all energy expenditure is
important, not just fat burning duringexercise.
