Exercise For Weight
Loss: Busting Plateaus
Chester J. Zelasko, Ph.D. | September 2004
Weight loss requires
that you eat less and exercise more. You can lose weight without exercising
but you’ll lose muscle mass as well as fat. That’s not really desirable
because muscle tissue is metabolically more active than fat tissue. In
effect, you’ll have to eat even less calories to lose weight.
While you may not like it, you have to move more to eat more. It’s even more
important when you reach a plateau while losing weight—and everyone reaches
a plateau at some point. This paper will explain how you can bust the
plateau without cutting your calories.
The Role of Exercise in Weight Loss
Very simply put, exercise uses calories. The more calories you use
exercising, the more you can eat and still lose weight. Interestingly,
exercise by itself is not an effective way to lose weight. There are at
least two reasons for this phenomenon.
First, we can’t possibly exercise enough to burn a sufficient amount of
calories and live the lives most of us live with work, family, and volunteer
activities. Exercise at a moderate level uses about 10 calories per minute.
Even walking for 30 minutes only uses about 300 calories—less if we exercise
at a low level. That still leaves 23.5 hours left in the day that you won’t
be using excess calories. As an aside, that’s why it’s important to be more
active the rest of the day. Park farther from the office, take the steps
instead of the escalator, anything to move your body that uses calories.
Second, and most disconcerting, is that we adapt quickly. That means our
body learns to be efficient. As we continue to exercise regularly, our body
learns to use the least number of muscle fibers to do the same job and to
use less energy doing it. That means that the number of calories used per
workout decreases. The exercise is good for our cardiovascular health and
for the body overall. It just won’t burn the same number of calories as it
used to and so we plateau. What can we do about it? Read on.
There are two ways a person can bust a weight loss plateau via exercise.
First, a person could exercise longer to use more calories. There is no
question that it will work. In fact, one popular train of thought is to
exercise longer and slower to burn more fat. How does that work?
When you exercise, your body would rather burn sugar (glucose) than anything
else. Why? Because it can maximize the energy it gets from that source. Fat
and, to a limited extent, protein can also provide energy but not as
efficiently. When you’re sitting comfortably in a chair, you’re using a
little more fat than carbohydrate—unless you ate something within the past
hour. When you rise and start walking, you shift to burning a higher
percentage of carbohydrates. Moving from a walk to a jog to a run to an
all-out sprint will continue to shift the carbohydrate percentage higher
until you are using carbohydrates exclusively. The theory behind fat-burning
exercise is to workout at a low level to burn more fat. While it works, the
problem is that you have to invest more time—something we hold as a
premium—to get to the fat burning stage (1). It’s just not an acceptable
solution for the lives most of us lead. (For a further explanation of
fat-burning exercise, see the Current Issues paper Fat Burning Exercise:
Separating Fact From Fiction.)
The second way to bust a plateau is to increase the intensity of exercise
for one or two workouts a week. There are two ways to increase intensity:
increase the speed or rate at which you exercise and/or increase the grade
or resistance of the exercise. For example, if you walk for exercise, you
can walk faster or you can walk up a hill. If you’re using an exercise bike,
you can increase the revolutions per minute or increase the resistance
setting of the bike. The same principle can be applied to any mode of
exercise: faster and/or harder.
The key is doing this in a systematic way. That’s called interval training
or IT for short. IT utilizes short bursts of high intensity work mixed with
normal pace. The length of the interval is dependent on your fitness level
but usually varies from 30 seconds to 2 minutes. For beginners, the interval
can be as simple as walking up two flights of stairs every third minute of
your walk. For those who are fitter, it may be one minute of jogging every
third minute of your walk. If you use an exercise bike, you can increase the
revolutions per minute from 60-70 rpm to 90-100 rpm for 30 seconds every
third minute. Keep the total minutes you workout the same whether it’s 30 or
45 minutes. Just intersperse the intervals regularly throughout the workout.
IT accomplishes several things. It induces muscle damage that takes energy
to repair. That increases metabolism and you use more calories. IT also
makes you fitter because you’re challenging your cardiovascular system more
than a typical walk or jog. Remember, only use the IT workout once or twice
per week. Too much of a good thing can end up leaving you without enough
time to recover.
When you hit that weight loss plateau, don’t despair. The solution lies in
pumping up the intensity to get you off and losing weight again! In short,
take the hills instead of the plains as you stride toward your better life.
- Zelasko, C. J. Exercise for weight loss: What are the facts? (1995).
Journal of the American Dietetic Association. 95:1414-1417.