How much protein is too much? Is there such a thing, and can it hinder my muscle-building goals?
Traditional bodybuilding dogma has always held that more protein is better. While this is true to a point, it can sometimes be more beneficial to decrease your protein intake and get those nutrients from other sources.
Think about your diet as a pie chart: x percent of that pie will be made up of protein, y percent fat, and the remainder carbohydrates. Regardless of the percentages you pick, they will always add up to 100%. You can never eat above 100%, so increasing one nutrient source will always decrease your intake of another.
If you continue to drive your protein intake upward, chowing down on more dry chicken breasts, then the protein percent of your pie will get bigger and bigger. This shrinks the fat and carbohydrate pie slices, thereby reducing your intake of essential fats, fiber, fruits, vegetables, and grains - all of which play important roles in a muscle-building diet. Depending on your fitness goals, there are actually ideal ranges for each macronutrient.
Synthesize, Don't Oxidize
We typically oversimplify protein, thinking it will always go toward growth. It actually does more than drive protein synthesis and provide amino acids for building muscle. Once those needs have been met, your body will actually break down and oxidize protein for energy. You don't necessarily want to be a protein oxidizer. You don't want to train your body to break down protein (dietary or muscle) and use it for energy. Just as switching from a high- to low-carbohydrate diet causes your body to increase the enzymes that burn fat as fuel, eating protein far beyond your body's ability to build muscle with it will cause increases in the enzymes that oxidize protein (both dietary and muscular) for energy.
"We typically oversimplify protein, thinking it will always go toward growth."
Maximizing Protein Synthesis
Instead of offering your body excess protein to oxidize for energy, your goal should be to maximize protein synthesis by eating the proper amount of protein at the right times.
We now know that there is both a protein threshold and timing component to protein's muscle-building ability. For whatever reason, people have long assumed that you can only digest 30 grams of protein at a time. Perhaps people thought our intestines contain a magical sensor that stopped absorbing protein once it registered 30 grams. Whatever the logic, your body can certainly digest much more than 30 grams of protein in one sitting.
However, 30 grams may be the proper amount of protein needed to get blood amino acid levels high enough to flip the muscle-building switch. The switch analogy is appropriate here. Like a light switch, once you flip the muscle-building switch, you can't turn it "more" on. When you hit the protein threshold and initiate protein synthesis, you can't initiate it more.
The other component to protein synthesis is flux. Giving yourself an infusion of amino acids throughout the day via proteins shakes, eggs, steaks and chicken isn't actually maximizing protein synthesis. Instead, you need a change in your blood amino acid levels. To reboost protein synthesis, blood amino acids need to drop and then spike. This occurs naturally when you eat 4-to-5 meals per day, but not if you're drinking a protein shake at every turn. I know it seems counterintuitive, but skip the constant protein shake sip and you'll actually maximize synthesis.
So, How Much?!
To maximize protein synthesis (and muscle growth), you know your goal: eat the right amount of protein at the right times. There are no steadfast numbers that say that X grams of protein are enough, where Y protein is too much. Over time, however, I have found that hypertrophy is maximized when protein constitutes 30-to-35% of your total calories.
This gives you enough protein to maximize protein synthesis and build muscle, but not so much that you displace the opportunity to hit optimal levels of other essential nutrients. 30-to-35% of your daily calories is still a lot of protein, and essentially double the RDA, but it falls within the National Academies of Medicine's "acceptable macronutrient distribution range, " so you don't need to worry about any adverse effects.