Most bodybuilders know that adequate protein consumption is critical to building muscle. You are what you eat, right? If you eat meat, you’ll become meaty. This may be an oversimplification, but it has some truth. In order to build muscles, you need to supply them with the essential amino acids found in protein. Deficiency of essential amino acids will impede your muscle growth. Therefore, high-quality, complete proteins are critical to success in dieting and training. Some bodybuilders look at protein with a “more is better” mentality. Others may not be able to afford this mentality, as protein is the most expensive macronutrient. Not to mention, and this is up for debate, excessive protein consumption might not be so healthy.
The recommended daily allowance for protein is only 0.8 grams per kilogram (g/kg) of bodyweight. For a 180-pound man, that would be only 65 grams of protein per day. Clearly, this won’t be enough for a bodybuilder. The ADA and ACSM put out a position stand recognizing that strength athletes like bodybuilders need 1.2 to 1.7g/kg per day.1 Furthermore, the International Society of Sports Nutrition (ISSN) recommends 1.4 to 2.0g/kg for physically active individuals.2Based on the ISSN recommendation, this would allow 164 grams of protein per day for the 180-pound bodybuilder. If you space your food out over five meals per day, these recommendations would allow for ~32 grams of protein per meal. Will this be enough for you? Are all proteins created equal?
How Protein is Used
The amino acids from protein act as building blocks for muscle proteins and molecular signals to build muscle. Complete proteins are those that provide all of the essential amino acids, which include the branched-chain amino acids (BCAAs). When the BCAA leucine reaches your muscle, it signals to your muscle to turn on the protein-making machinery. Muscle proteins make up the contractile elements of muscle. The more you have, the bigger and stronger your muscles.
Protein can also act as an energy source. Oxidation of proteins for energy produces similar calories as carbohydrate, ~4 calories per gram of protein. However, protein and carbohydrate have different effects on your physiology. Consumption of a carbohydrate meal results in significantly higher insulin release than a protein meal. Insulin turns your muscles and fat into storage mode, shutting down fat burning and turning on storage of glucose as glycogen. A protein meal does not have such a profound effect on insulin release and thus doesn’t turn off fat burning like carbohydrates do. Also, a protein meal results in more food-induced thermogenesis.
Protein Needs and Limits
Bodybuilders utilize the ability of protein meals to boost their metabolism for getting ripped. In this case, protein is consumed in higher quantities to provide not only building blocks but also energy substrate. When a dieting bodybuilder goes to a low-carb diet to get in shape, he has to increase protein and fat consumption to avoid rapid loss of muscle. He may boost his protein intake up to 3 to 3.5 grams per kilogram per day. Unfortunately, there aren’t many studies to support the safety of protein intakes this high, but anecdotally it seems pretty safe, at least in the short term, and there are some populations who live at >3g/kg/d their whole lives.3 There isn’t a defined tolerable upper limit to protein intake, but the acceptable macronutrient distribution ranges (AMDR) set by the Institute of Medicine suggests that protein shouldn’t be more than 35 percent of your macronutrient calories.3 This can conflict with the goals of a dieting bodybuilder.
Cuthbertson and colleagues demonstrated that 10 grams of essential amino acids was sufficient to maximally stimulate muscle protein synthesis at rest.6 This dose would correlate to approximately 25 grams of a complete protein like whey isolate or meats. Older individuals may need 20 to 30 percent more protein because of age-related decline in absorptive capacity.16Muscle protein synthesis goes through a rise and fall over the course of three to four hours after a meal.7 Thus, because of the refractory nature of the protein synthesis machinery, it makes sense that protein only needs to be consumed five times per day.13 This is the basis of my “G.A.I.N. Plan” five meal per day diet (5MAD).
Splitting Up Protein Intake
Data supports that your food, or protein, should be divided up throughout your day.11Epidemiologic data suggests that most people put a heavy weight on the consumption of their protein at dinner. Breakfast often has the lowest amount of protein. A recent study compared the “typical” skewing of protein later in the day with a more even spread over three meals.11 They compared spreading 90 grams of protein evenly over three meals (30, 30, 30) versus skewing the protein (10, 15, 65). By more evenly distributing protein throughout the day, the researchers found 25 percent greater 24-hour muscle protein synthesis rates. This research also goes along with a study that showed no further improvement in muscle protein synthesis was achieved by consuming a 12-ounce steak with 90 grams of protein over a 4-ounce steak with 30 grams of protein.12 Now if we take into consideration protein timing and the post-workout anabolic window, we may be able to improve upon their results.
If 25 grams of protein is all that is needed, then is 125 grams per day all you need on the 5MAD diet? Even for a 200-pound bodybuilder? Probably not. There aren’t a whole lot of studies that have had subjects that match the typical bodybuilder who tears down a lot of muscle in the gym only to build even more. Besides, unless you match the same weight, age and sex of the subjects in the research studies, you probably need more protein, as is suggested by the ISSN.2
Leucine and Muscle Protein Synthesis
The leucine content of food has been shown to directly correlate with increases in muscle protein synthesis. Research suggests that there may be a minimum amount of leucine needed per meal to maximally stimulate muscle protein synthesis; this ranges between ~2 to 3 grams per meal (0.05mg/kg bodyweight). In fact, one study demonstrated 33 percent greater muscle protein synthesis with 3.5 grams of leucine versus 1.87 grams given during a workout as part of an essential amino acid solution.5 For whey protein isolate, which is relatively leucine rich, 20 to 30 grams of protein will meet the need to maximize muscle protein synthesis in most people. For proteins like beef and fish, this could require up to 35 grams of protein to achieve adequate leucine quantities.
Protein Amounts and Age
Age definitely comes into the equation when determining how much protein is needed for maximal protein synthesis response after training. One study showed that a 20-gram whey protein shake is plenty to maximize muscle protein synthesis in young adults.8 Another recent study suggested that 20 grams of egg protein was also sufficient.10 However, 20 grams is not enough for 70-year-olds, as they may need as high as 40 grams of whey protein to overcome their “anabolic resistance.”9 These studies suggest that any higher amounts of protein will only result in the oxidation of the amino acids and formation of the potentially toxic performance-reducing substance called urea.
Inconsistencies
A closer look at these studies can reveal some inconsistencies. For instance, in the study by Witard et al., the subjects were fed a high-protein breakfast with 45 grams of an undisclosed protein source. Why a 45-gram breakfast? Then the subjects did resistance training at three hours after breakfast. Within 45 minutes, they finished their exercise and consumed either 20 or 40 grams of whey protein isolate. They concluded that the 20-gram shake was sufficient at maximizing muscle protein synthesis even though their data couldn’t rule out a 14 percent further increase at 40 grams because the study was underpowered (needed more subjects). The egg protein study also trended higher with an almost 10 percent greater increase at 40 grams despite lack of statistical significance. Larger studies are needed to be certain that we should stop at 20 grams post-workout.
Nutrient timing appears to be very important when it comes to maximizing muscle growth. Recall the study we discussed earlier that suggested that 3.5 grams of leucine given during training was better than 1.87 grams at increasing muscle protein synthesis. Well, when the same doses are given at rest, there doesn’t appear to be a significant difference in the protein synthesis response between the two doses.14 However, the higher dose of leucine at rest appears to limit muscle protein breakdown. I would think that the excess leucine may be degraded to its metabolite HMB, which has muscle-sparing properties. Many other studies have explored the post-workout “anabolic window” where muscle is extra sensitive to insulin and nutrients, with protein and carbohydrate producing a larger spike in protein synthesis. Some data suggests that this is something that has been made up in the lab because so many studies are done in a fasted exercise protocol.15 Consequently, any food given after a fast AND a workout is going to produce a large protein synthesis response. It’s like starving someone and then force-feeding them.
Get Meaty
Despite all of the data presented in this article, it is my opinion that 1 gram of protein per pound of bodyweight divided over five meals ensures maximal leucine and essential amino aciddelivery to muscle to stimulate and fuel muscle growth. I am certain that no study mentioned here would suggest that this would result in protein deficiency in anyone. This quantity is safe in most people and won’t likely lead to performance decrement. If protein cost is prohibitive, cutting back to the ISSN or ACSM recommendations is acceptable. If you are a vegetarian, add leucine to your meals. Eat your meat and get MEATY!
Dr. Victor Prisk is a board certified orthopaedic surgeon and IFBB professional bodybuilder in Pittsburgh, PA. Dr. Prisk is an active member of the GNC Medical Advisory Board and creator of the “G.A.I.N. Plan.” He is an NCAA All-American gymnast, champion swing dancer and NPC Welterweight National Champion
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