Dear Science,
My friend’s trainer at the gym told her she didn’t need to buy
any of the fancy supplements they were selling there. He said she
should just take an aspirin and drink a glass of grapefruit juice every
morning, and it would speed up her metabolism. Is the grapefruit
juice/aspirin thing true? Do the supplements they sell at the gym do
anything real? Thanks!
Burning Belly
Dietary supplements are a pit of despair for science, a den of
bold unproven claims held to irrational depths by legions of
believers. Before overturning that rock, let’s talk about
metabolism.
Like cars, we consume energy as we go about our
business—measured in kilocalories; for surreal reasons, food
packages just call them calories. One kilocalorie is the energy needed
to heat a liter of water one degree centigrade. A typical person
requires somewhere between 1,500 to 3,500 kilocalories worth of energy
per day just to exist—called the basal metabolism. This is what
your friend wants to increase, to speed up—becoming less
efficient, more Hummer than Prius.
Tremendous variation exists from individual to individual in this
rate; you can experimentally determine yours. Over the course of a
couple weeks, weigh yourself each day and then calculate your seven-day
rolling average weight to see if your weight changed over time. Record
what and how much you eat over this time, using food calorie tables to
determine the total calories you ate during the test period. A program
like CRON-o-Meter is perfect for this. Each pound of fat contains about
3,500 kilocalories, so for each pound you gained or lost, subtract or
add 3,500 kilocalories respectively from the total. Then calculate the
average number of calories you ate per day. This is your basal
metabolism. Science, doing this, found his basal metabolism is about
a thousand kilocalories less a day than the average person’s of his
gender, height, weight, and activity level; he fears cookies.
An astounding number of drugs can increase or decrease the basal
metabolism. For example, ephedrine—known to most people around
here as pre-meth—increases basal metabolism and suppresses
appetite. Thanks to hideous side effects, this is a poor long-term
dieting strategy.
What about those gym supplements? Like all supplements, there is
no legal requirement for testing if they are safe, if they work, or
even what is in the supplement; for all we know, many supplements
are shredded Chinese newspapers.
What of the trainer’s combination? Aspirin increases the effect of
drugs like ephedrine. Grapefruit juice can slow down the destruction
and removal of a wide variety of drugs, increasing the effect of
metabolism-modifying medications. Like the supplements, who knows if
they’ll increase your basal metabolism. Science suggests you do
some self-experimentation and report back.
Inquisitively Yours,
Science
Send your science questions to
dearscience@thestranger.com
