How much is enough?
As a scientist with a focus on nutritional interventions, I take
serious issue with the way the RDA was calculated. And, if it were
up to me, I'd explain to Testosterone readers the
benefits and drawbacks of different methods for measuring how the
body uses protein. My editor, though, has other ideas.
He says it makes his eyeballs bleed to read phrases like
"indicator amino acid oxidation," and I respect that.
Still, for the record, I think there's a strong scientific
argument against the methods used to calculate RDAs, and a strong
argument in favor of a more accurate system.
So I'll spare you the technicalities of that argument.
Instead, let's look at what's behind Door #2:
In a fat-loss study conducted recently at our lab at OU, we
recruited a group of sedentary but otherwise healthy adults (both
genders), and assigned each person to one of three groups.
The first group (shown in the charts below as CON) did nothing
except allow us to keep track of their diet. Like typical American
adults, they eat more protein than the RDA suggests (about a
half-gram per pound of body weight per day, which is 21 percent
higher than the RDA), and about three grams of carbohydrate for
every gram of protein.
The second group (EX) ate that same diet, but added exercise:
two days a week of strength training, three days a week of
endurance work.
The third group (EXFS) exercised and also added one or two
protein shakes a day. They averaged 0.72 grams of protein per pound
of body weight per day. That's about 60 percent more protein
than the other two groups. [2]
The first thing that jumps out: Even with a crappy diet, the
first exercise group (EX) lost some fat — about two pounds in
the 10-week study. But by adding one or two protein shakes a day
(one shake per day for the first two weeks, two shakes for the next
eight weeks), the final group lost more than twice as much,
dropping about five and a half pounds, on average.
When you put newbies on a five-times-a-week workout program that
includes strength and endurance, you expect them to add a bit of
muscle while they drop some fat. So it's no big surprise that
the first exercise group would gain a bit of muscle (about half a
pound) while dropping some fat.
As before, the extra-protein group got twice the benefit, adding
a pound of muscle to go with the loss of five pounds of fat. Even
for newbies, that's not bad for just 10 weeks!
Both exercise groups increased their strength, of course. And,
again, the group with extra protein saw slightly bigger gains
— which is to be expected, since muscle strength is so
closely related to muscle size.
If you're wondering why the non-exercising control group
also increased in strength, I should note that it's such a
slight gain as to be statistically nonsignificant — it could
be a fluke, or it could be that one or two people in the control
group got some exercise we didn't know about. Either way, it
doesn't matter.
The exercise group getting more protein also improved their
endurance more than the non-supplemented exercisers. We
weren't surprised by this finding; we figured that the group
getting more protein would experience more complete recovery
between workouts, so it makes sense that they'd be able to
work out harder and see bigger improvements in their aerobic
performance.