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.

So what can we take away from this study?

• If you want to lose fat, more protein is crucial – at least a half-gram of protein per pound of body weight per day. That's at least 100 grams per day if you weigh 200 pounds.
• Just as important, you probably need to get fewer than 40 percent of your total daily calories from carbohydrates. In our study, the group getting daily protein shakes also cut their carb intake to about 43.5 percent. If they'd gone lower, research suggests, they would've gotten even better results.
• If you have a lot of fat to lose, and your goal is a dramatic change in your body composition, research shows you should have at least two-thirds of a gram of protein per pound per day (about 135 grams for a 200-pounder), and fewer than 150 grams of carbs a day. (The subjects in our study averaged about 190 grams of carbs a day, and still saw decent changes in body composition in 10 weeks.) At worst, you should never consume more than 1.5 grams of carbs for every gram of protein.

Those numbers, however, are for beginners. For serious lifters and competitive strength athletes, we have to bump up the protein.

The International Society of Sports Nutrition, in a 2007 position statement, concluded that bodybuilders and strength/power athletes require just under a gram of protein per pound per day. [3]

But even the ISSN statement looks at studies based on nitrogen balance, which underestimates how your body actually uses protein by a large amount – 40 to 55 percent. (I'd tell you how I came up with that number, but I can feel my editor staring me down with his bleeding eyeballs.)

More sophisticated estimates of protein requirements suggest that you can break it down in terms of individual essential amino acids ("essential" means your body can't make them from other amino acids in your diet). I've done that in the following chart, adding 40 percent to the totals for regular folks to estimate how much T-Nation readers need to reach their goal of improved body composition:

* BCAAs – branched-chain amino acids – include the first three essential aminos on the list: isoleucine, leucine, and valine.

Essential aminos are found in the greatest concentration exactly where you expect to find them: milk, eggs, meat – animal protein sources, in other words. A serving of Metabolic Drive, for example, contains 20 grams of protein, about 9 of which are essential amino acids.

Donald Layman, a nutrition professor at the University of Illinois, offers a simple solution: Eat a minimum of 30 grams of protein for breakfast, and at least 30 grams of protein at every subsequent meal, with meals no more than five or six hours apart. [4]

Researchers at Cal State-East Bay came up with a more complex formula for T-Nation types: Each time you have a protein-containing meal, you should have the equivalent of 23 to 33 grams of protein in that meal. They also concluded that you'll get the biggest anabolic response if you have these meals about every two hours. [5]

The first is probably too casual for muscleheads like us. The second is a bit fanatical, even by our standards. So here's the middle ground: go for six meals a day, each containing at least 25 grams of protein.

That's a general, all-purpose recommendation. Use the following system to tailor your protein consumption to your current needs.

1. Choose your current training cycle from the list that follows.
2. Determine your desired (goal) body weight, in pounds.
3. Multiply your desired body weight by the suggested grams of protein per pound of body weight per day.
4. Results from Step 3 provide you with your recommended grams of protein per day.
5. Divide your total daily protein into six meals per day.
6. If Step 5 suggests you need fewer than 25 grams of protein per meal, round up to 25. In other words, everyone using this system will have at least 150 grams of protein per day.

Off-Season or Moderate

You have no specific goals beyond maintaining your current body composition. You need 0.8 grams of protein per pound of body weight per day.

Moderate to High Intensity

You're pushing yourself to build muscle, gain strength, and/or lose fat. You need 1 gram of protein per pound of body weight per day.

High Intensity or Pre-Competition

You're in serious training, possibly preparing for a bodybuilding contest or some other competition that requires peak performance. You need 1.36 grams of protein per pound of body weight per day.

While optimal protein needs will continue to be a hot topic for discussion for years to come, it's good to have some research to back up assertions that are in conflict with the recommendations of lay people and lay nutritionists.

1. Rand WM et al. Am J Clin Nutr 2003;77:109–27
2. Lockwood et al. Nutr Metab 2008, 5:11
3. Campbell B et al. J Int Soc Sports Nutr 2007, 4:8
4. Layman DK. J Am Coll Nutr 2004, 23(6 Suppl):631S-636S
5. Wilson J and Wilson GJ. J Int Soc Sports Nutr 2006;3(1):7-27