3500 Calories To Lose A Pound - Is This Formula All Wrong?
By Tom Venuto, NSCA-CPT, CSCS
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)
(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: http://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
