By Tom Venuto, NSCA-CPT, CSCS
www-BurnTheFat-com
www-BurnTheFat-com
Most fitness conscious people have heard that there
are 3,500 calories in a pound of fat, so if you create a deficit of 3500
calories in a week, you lose a pound of weight. If you create a deficit of 7000
calories in a week, you lose two pounds, and so on. Right? Well, not so fast…
Dr. Kevin Hall, an investigator at the National
Institute of Health in Bethesda has done some interesting research about the
mechanisms regulating human body weight. He recently published a new paper in
the International Journal of Obesity that throws a wrench in works of the “3500
calories to lose a pound” idea.
Some of the equations in his paper made my head
hurt, but despite the complex math he used to come to his conclusions, his
article clearly prompts the question, "3500 calories to lose a pound of
WHAT?" His paper also contained a lot of simple and practical tips you can
use to properly balance your caloric intake with output, fine tune your calorie
deficit and help you retain more muscle when you diet.
Below, I’ve distilled some of the information into
a simple bullet-point summary that any non-scientist can understand. Then I
wrap up with my interpretation of how you can apply this data in your own fat
loss program:
Calculating the calories required to lose a
pound and fine-tuning your caloric deficit
- 3500
calories to lose a pound has always been the rule of thumb. However, this
3500 calories figure goes back to research which assumed that all the
weight lost would be adipose tissue (which would be ideal, of course).
- But
as we all know (unfortunately), lean body mass is lost along with body
fat, which would indicate that the 3500 calorie figure could be an
oversimplification.
- The
amount of lean body mass lost is based on initial body fat level and size
of the calorie deficit
- Lean
people tend to lose more lean body mass and retain more fat.
- Fat
people tend to lose more body fat and retain more lean tissue (revealing
why obese people can tolerate aggressive low calorie diets better than
already lean people)
- Very
aggressive low calorie diets tend to erode lean body mass to a greater
degree than more conservative diets.
- whether
the weight loss is lean or fat gives you the real answer of what is the
required energy deficit per unit of weight loss
- The
metabolizable energy in fat is different than the metabolizable energy in
muscle tissue. A pound of muscle is not 3500 calories. A pound of muscle
yields about 600 calories.
- If
you lose lean body mass, then you lose more weight than if you lose fat.
- If
you create a 3500 calorie deficit in one week and you lose 100% body fat,
you will lose one pound.
- But
if you create a 3500 calorie weekly deficit and as a result of that
deficit, lose 100% muscle, you would lose almost 6 pounds of body weight!
(of course, if you manage to lose 100% muscle, you will be forced to wear
the Dieter’s Dunce cap)
- If
you have a high initial body fat percentage, then you are going to lose
more fat relative to lean, so you may need a larger deficit to lose the
same amount of weight as compared to a lean person
- Creating
a calorie deficit once at the beginning of a diet and maintaining that
same caloric intake for the duration of the diet and after major weight
loss fails to account for how your body decreases energy expenditure with
reduced body weight
- Weight
loss typically slows down over time for a prescribed constant diet (the
“plateau”). This is either due to the decreased metabolism mentioned
above, or a relaxing of the diet compliance, or both (most people just
can’t hack aggressive calorie reductions for long)
- Progressive
resistance training and or high protein diets can modify the proportion of
weight lost from body fat versus lean tissue (which is why weight training
and sufficient protein while on calorie restricted diets are absolute
musts!)
So, based on this info, should you throw out the
old calorie formulas?
Well, not necessarily. You can still use the
standard calorie formulas to figure out how much you should eat, and you can
use a 500-1000 calorie per day deficit (below maintenance) as a generic
guideline to figure where to set your calories to lose one or two pounds per
week respectively (at least that works “on paper” anyway).
Even better however, you could use this info to
fine tune your caloric deficit using a percentage method and also base your
deficit on your starting body fat level, to get a much more personalized and
effective approach:
15-20% below maintenance calories = conservative
deficit
20-25% below maintenance calories = moderate deficit
25-30% below maintenance calories = aggressive deficit
31-40% below maintenance calories = very aggressive deficit (risky)
50%+ below maintenance calories = semi starvation/starvation (potentially dangerous and unhealthy)
20-25% below maintenance calories = moderate deficit
25-30% below maintenance calories = aggressive deficit
31-40% below maintenance calories = very aggressive deficit (risky)
50%+ below maintenance calories = semi starvation/starvation (potentially dangerous and unhealthy)
(Note: According to exercise physiologists Katch
& Mcardle, the average female between the ages of 23 and 50 has a
maintenance level of about 2000-2100 calories per day and the average male about
2700-2900 calories per day)
Usually, we would suggest starting with a
conservative deficit of around 15-20% below maintenance. Based on this
research, however, we see that there can be a big difference between lean and
overweight people in how many calories they can or should cut.
If you have very high body fat to begin with, the
typical rule of thumb on calorie deficits may underestimate the deficit
required to lose a pound. It may also be too conservative, and you can probably
use a more aggressive deficit safely without as much worry about muscle loss or
metabolic slowdown.
If you are extremely lean, like a bodybuilder
trying to get ready for competition, you would want to be very cautious about
using aggressive calorie deficits. You’d be better off keeping the deficit
conservative and starting your diet/cutting phase earlier to allow for a slow,
but safe rate of fat loss, with maximum retention of muscle tissue.
The bottom line is that it’s not quite so simple as
3,500 calories being the deficit to lose a pound. Like lots of other things in
nutrition that vary from person to person, the ideal amount of calories to cut
“depends”…
Note: The Burn the Fat, Feed The Muscle program not
only has an entire chapter dedicated to helping you calculate your exact
calorie needs, it was designed very specifically to keep a fairly conservative
approach to caloric deficits and to maximize the amount of lean tissue you
retain and minimize the amount of metabolic adaptation that occurs when you’re
dieting. The approach may be more conservative, and the fat loss may be slower,
but it has a better long term track record… You can either lose weight fast,
sacrifice muscle and gain the fat back like 95% of people do, or lose fat slow
and keep it off forever like the 5% of the people who know the secrets. The
choice is yours. For more information, visit: www-burnthefat-com
References:
Forbes GB. Body fat content influences the body
composition response to nutrition and exercise. Ann NY Acad Sci. 904: 359-365.
2000
Hall, KD., What is the required energy deficit per
unit of weight loss? Int J Obesity. 2007 Epub ahead of print.
McArdle WD. Exercise physiology: Energy, Nutrition,
and Human performance. 4td ed. Williams & Wilkins. 1996.
Wishnofsky M. Caloric equivalents of gained or lost
weight. Am J Clin Nutr. 6: 542-546.
About the Author:
Tom Venuto is a natural bodybuilder, certified
strength and conditioning specialist (CSCS) and a certified personal trainer
(CPT). Tom is the author of "Burn the Fat, Feed The Muscle,” which teaches
you how to get lean without drugs or supplements using methods of the world's
best bodybuilders and fitness models. Learn how to get rid of stubborn fat and
increase your metabolism by visiting: www-burnthefat-com
