Don’t Believe the Hype


I recently got an email from a client asking me my opinion about a diet book.  She sent me the book’s basic outline and it didn’t look outrageous – cut out refined carbs, eat lean protein and lots of veggies, drink only water, etc.  Some of the recommendations could be considered a little suspect, but overall it wasn’t a crazy program.   What really caught my eye was that the author guaranteed a “20lb. weight loss in a month.”  Twenty pounds in a month….really?!  So, I sat down with my little calculator and started crunching some numbers to figure out exactly how that would work.

Heavy artillery in the battle of the bulge

If we all buy into the basic premise of the law of thermodynamics, weight loss is a calories in – calories out formula.  If you eat more than you burn, you’ll gain weight.  Eat less than you burn, you’ll lose weight.  It’s not exactly that simple, but let’s use it as a principle from which to extrapolate, shall we?

I’m going to go on the assumption that when people say they want to “lose weight,” they really mean they want to lose fat.

For the record, that’s not muscle tissue…

So, one pound of body fat is essentially 3500 calories of stored energy.  To lose it, you’d need to decrease calories by that amount, increase your activity by that amount, or some combination of caloric deficit and increased energy output.  Eat less, move more…you get the idea.

So, losing 20 pounds of fat equates to using 70,000 stored calories.  Taking an average of thirty days in a month, that comes out to a 2,333 calorie deficit, or about 2/3 pounds lost every day of the month.  I’m not going out on a limb by saying those kinds of results would be very atypical.  An ambitious but achievable goal is more on the order of 1-2 pounds per week, or 4-8 pounds in a month.  Based on the math, I’m sure you can see why.

My message is to beware of overblown claims related to diet and fitness.  Lose 20 pounds in a month, pack on 30 pounds of muscle in 30 days, get washboard abs in just 3 minutes a day three days a week – if it sounds too good to be true, it is.

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Michael Bento is an Advanced Trainer at the Clubs at Charles River Park. He holds a Masters degree in Human Movement and is certified by the National Academy of Sports Medicine as a Corrective Exercise Specialist and Performance Enhancement Specialist.

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