Can you get too much protein? Good question. With M&F and your gym buddies preaching the minimum of 1 gram per pound of bodyweight and a lot of mainstream media talking about the dangers of that standard, things can get a bit confusing. This two-part series, presented in easy-to-follow Q&A format, should help assuage your fears.
Q: Why does M&F recommend such comparatively high amounts of protein?
A: We have a lot of reasons, but probably the most important one is this: It works to give you the physique you're looking for. "Muscle growth happens when protein synthesis exceeds protein breakdown," Elliott says. "The availability of protein plays an important role in that process, so it follows that increased amino acid availability—such as what is provided by the intake of dietary protein—will result in a greater anabolic response."
It has been proven that the more protein you eat, the more protein synthesis occurs in your muscles. In a study published in The Journal of Physiology in 2003, researchers found that subjects who had been given an infusion of amino acids experienced a boost in muscle protein synthesis. No surprise, right? The amazing thing was that the rate at which subjects built muscle protein increased as the amount of protein in their bloodstreams increased. Therefore, the more protein you eat, to a degree, the more muscle you'll build—all day long, with or without exercise.
We have other reasons for our recommendations, too. One of them is pretty basic: You're most likely taking supplements (branched-chain amino acids, beta-ecdysterone) that boost protein synthesis, but if you don't have a well of protein for your muscles to draw on, those supplements aren't going to do much. Another reason is because there's evidence that eating protein can keep you lean. For one thing, it's the hardest macronutrient for your body to digest, which means your body has to use more energy (calories) to break it down. Protein also increases the amount of a hunger-blunting peptide called PYY in your bloodstream, meaning you won't be hankering for munchies soon after eating a high-protein meal.
Yet another reason for our protein recommendations is more complicated, but no less rational. In fact, it's all about ratios. In addition to deciding the RDA for nutrients, the FNB recently established what it calls the Acceptable Macronutrient Distribution Range (AMDR) for protein, carbohydrates and fat to tell us what percentage of our calories should come from each. The AMDR for protein is between 10% and 35% of total calories. Now, to support the kind of body you're boasting (or looking to build), you have to put down a lot of calories.
Our advice is generally that a 180-pound guy should eat 18 calories per pound of bodyweight per day, or about 3,240 calories. And that's just to maintain his mass. So let's do the math: Thirty-five percent of 3,240 is 1,134 calories of protein; divide that by 4 (the number of calories in a gram of protein), and you get 284 grams of protein per day. Divide that by our example's bodyweight (180), and you get 1.6 grams of protein per pound of bodyweight per day.
It just goes to show that bodybuilders generally eat within the FNB's acceptable range; it's the FNB that's not familiar with how much food bodybuilders need. Because you consume way more calories (sometimes almost twice the requirement of the average couch-sitter) per day, you have to eat that much more protein. Otherwise, as we discovered by doing more math, you'd be in for an equally fat gut. We plugged in the numbers to see what our 180-pound bodybuilder would be eating if he stuck with the RDA for protein and ate only 0.8 gram of protein per pound of bodyweight per day. Since he'd be eating only 144 grams of protein, he'd have to fill his plate with something else—like, oh, 500 grams of carbs. Needless to say, that's more than his body could use for energy, so all the excess would head straight for his fat stores.