Protein is generating buzz in headlines and high protein diets are being praised as viable options for simultaneously losing weight and building muscle. So, what differentiates a high-protein diet from a low-protein diet? How does one calculate protein needs? Does protein source matter?
As a longtime weightlifter and competitive bodybuilder, I have paid careful attention to the levels and sources of protein in my diet for many years. The “macros” plan I have followed has served me well and is a practical plan for most people.
With this approach, the diet is founded on total caloric intake, with ranges for calories appropriated to the three macronutrients—protein, carbs and fats. The first step is to determine caloric needs based on goals, and then set levels for protein, followed by fats and carbs. The final touch is to convert these numbers to foods.
Protein is the body’s structural and functional macronutrient while carbs and fats are its energy macronutrients. While protein can be metabolized for energy, this is not ideal. This occurs only when there is an abundance of protein and inadequate carbs and fats to support normal energy production.
Because of its significance, it behooves you to figure out where you are with protein levels and adjust, if necessary, to achieve health and fitness goals.
Protein Guidelines
It can be challenging to determine protein needs because they vary by individual and because there are no clear-cut answers. However, there are a few places to start. One is the Dietary Guidelines for Americans (DGA) established by the U.S. Department of Agriculture (USDA) and the U.S. Department of Health and Human Services. Updated every five years, the latest guidelines were revised in 2020.
Protein recommendations are based on the calorie level of the diet, with adjustments for gender, age and activity level. For example, diets at the 2,000-calorie level should get 5.5 ounces of protein equivalents per day, with breakdowns of 26 ounces of meat, poultry and eggs, 8 ounces of seafood, and 5 ounces of nuts, seeds and soy products per week. The Acceptable Macronutrient Distribution Range (AMDR) for protein among adults is 10-35% of caloric intake.
Unfortunately, this is not very useful for most people as calorie levels are not tied to either body height or weight. Rather they are based on “average” height and weight. If you are a moderately active 40-year-old woman, guidelines suggest a daily intake of 2,000 calories and 5.5 ounces of protein. But the caloric and protein needs of a woman who is 5’ 2” and 130 pounds look very different than those of a 6’ 2” woman who weighs 280 pounds. Thus, the DGA guidelines are a starting point at best.
This is also why the percentage daily value on nutrition labels should be taken with a grain of salt. This number is based on a 2,000-calorie diet. More useful is the protein grams per serving, which is mandatory for all food labels. The U.S. Food and Drug Administration regulates most food labels while the USDA Food Safety and Inspection Service regulates meat and poultry labels.
| Females 19-30 | Females 31-50 | Females 51+ | Males 19-30 | Males 31-50 | Males 51+ | |
|---|---|---|---|---|---|---|
| Calorie Level | 2,000 | 1,800 | 1,600 | 2,400 | 2,200 | 2,000 |
| Protein (grams) RDA | 46 | 46 | 46 | 56 | 56 | 56 |
| Protein (% kcal) AMDR | 10-35 | 10-35 | 10-35 | 10-35 | 10-35 | 10-35 |
A guideline that considers body weight is the Recommended Dietary Allowance (RDA) established by the Food and Nutrition Board of the Institute of Medicine. The current protein recommendation is 0.8 grams of protein per kilogram of body weight or 0.36 grams per pound of body weight. This equates to 46 grams of protein for a sedentary woman weighing 128 pounds and 56 grams for a sedentary man weighing 154 pounds.
Keep in mind that RDAs are intake levels judged to adequately meet the nutrient needs of practically all healthy persons. They may not meet the needs required for optimal health and performance, muscle hypertrophy and recovery. And they are not based on body composition.
Protein Needs Likely Far Greater
More and more, scientific literature points to higher protein requirements, especially for active and moderately active individuals, aging Americans and those who want to lose weight. Generally, protein requirements for adults range from 0.8 to 2.2 grams of protein per kilogram of body weight. Training sessions of longer duration or intensity require higher protein levels. As well, strength training requires higher protein levels than cardiovascular training.
Recent developments in methods used to determine protein needs suggest higher minimums for protein than the DGA and RDA. Using indicator amino acid oxidation (IAAO), Pencharz, Elango and Wolfe (2016) showed minimum protein requirements have been underestimated by 30-50%. In practice, they suggest 1.5 to 2.2 grams of protein per kilogram of body weight be consumed from a variety of high-quality proteins. Using the same IAAO method, Bandegan et al. (2017) found similar results in a study on male bodybuilders and Keto et al. (2016) proved endurance athletes have higher protein requirements than their sedentary peers.
Demling and DeSanti (2000) showed it is also possible to simultaneously lose body fat and increase lean mass and strength with a lower calorie, higher protein diet and resistance training. Josse, Atkinson, Tarnopolsky and Phillips (2011) found similar results with high-protein, high-dairy diets and exercise in a study of overweight and obese women.
To calculate your protein needs, a practical approach is to consider contemporary research and your level of activity, as shown in the table below.
| Activity Level | Exercise | Protein (grams/kilogram body weight) |
|---|---|---|
| Sedentary | None | 0.8 to 1.2 |
| Moderately Active | Cardiovascular | 1.2 to 1.6 |
| Moderately Active | Resistance Training | 1.5 to 2.0 |
| Moderate to Vigorous | Cardiovascular | 1.5 to 2.0 |
| Moderate to Vigorous | Resistance Training | 1.7 to 2.2 |
To find your numbers based on pounds of bodyweight, use the following formula: body weight pounds / 2.2 x protein requirement = protein grams. For example, the protein needs of a moderately active cardio training woman might look like this: 135 / 2.2 x 1.2 = 74 grams protein. A vigorously active resistance training man might have these numbers: 210 / 2.2 x 2.2 = 210 grams protein.
Another approach is to calculate protein intake based on fat-free mass. But this requires knowledge of body composition. Research by Helms et al. (2014) suggests protein intakes of 2.3 to 3.1 grams per kilogram of fat-free mass (1.0 to 1.4 grams per pound of fat-free mass) when dieting or for lean, resistance training individuals in a caloric deficit.
Protein Sources
Keep in mind that all protein sources are not created equally. Protein quality is dictated by the number of essential amino acids (EAAs) the food contains and its digestibility. Protein quality also refers to the completeness of a protein. A food that contains all EAAs in appropriate quantities is called a complete protein. In general animal proteins and soy are complete proteins and plant proteins are incomplete.
Vegetarians and vegans need to carefully plan their diets to ensure they are getting adequate levels of EEAs. One strategy is to consume a variety of protein sources, including complementary proteins. Some common complementary proteins are rice and beans, wheat and peanut butter, pasta and peas, and lentils and almonds. Complementary proteins need not be paired in the same meal but should be consumed on the same day as total daily EEA is more important than EEAs per meal.
Adequate levels of the amino acid leucine are critical for active individuals and athletes. Leucine is a primary factor for increasing muscle protein synthesis and facilitating muscle recovery and growth. Sources high in leucine are whey supplement (2.6 grams per standard serving), casein supplement (2.3 grams), soy supplement (2.1 grams), chicken breast (2.0 grams), pork loin (1.9 grams) and wild-caught salmon (1.8 grams). A single whole egg has 0.54 grams of leucine.
When calculating protein needs, be sure to consider total calories as well. If your goal is weight loss, upping the protein content won’t help you take off pounds since weight loss hinges on being in a caloric deficit.
Consider the entire protein package and what comes with the protein, including micronutrients (vitamins and minerals) and the two other macronutrients: fat and carbs. A big juicy steak might be loaded with protein, but it is also loaded with fat. Your post-workout protein bar might be a candy bar in disguise, loaded with sugar, fat and additives that negate health benefits.
Protein Timing
Protein timing is hotly debated at the gym. It is gym culture to bring a shaker bottle pre-loaded with protein mix to capitalize on the so-called “anabolic window” that follows a training session. More important to muscle hypertrophy and recovery, though, is the total daily protein consumption.
Nevertheless, there are advantages to strategically timing protein intake throughout the day due to an “anabolic threshold” for muscle protein synthesis (MPS). In a study by Areta et al. (2013), athletes consumed 80 grams of whey protein in differing amounts and intervals 12 hours post-training. MPS for 20 grams of protein consumed four times at three-hour intervals was superior to 40 grams every six hours or 10 grams across eight servings. Athletes consuming 20 grams per meal crossed the threshold more often than athletes consuming 40 grams. And 10 grams was not enough protein to stimulate MPS.
The benefit of even consumption of protein across meals on MPS was documented by Mamerow et al. (2014). One group ingested equal amounts of protein across three meals (about 30 grams each) while the second group consumed the same amount of protein in a skewed distribution of 10-15 grams for breakfast and lunch and 65 grams for dinner. MSP rates were 25% greater for the participants with even protein distribution. This contradicts standard American habits, which lean towards high-carb, low-protein breakfasts and high-protein dinners.
From a practical standpoint, to maximize anabolism, consume at least four meals of high-quality protein every three hours at a rate of 0.4 grams of protein per kilogram of body weight (Schoenfield and Aragon, 2018).
Consuming protein as a pre-exercise snack may be helpful if protein has not been consumed 1-3 hours before training. Protein during a workout (beverage with 1-2% protein) may only be necessary for very long training sessions or endurance events. Of equal significance to protein in the post-workout meal are carbs, ingested in a ratio of 3:1 or 4:1 carbs-to-protein.
A fueling strategy for strength athletes is illustrated in the graphic below.
Protein Considerations for Aging Americans
Changes in body composition are a natural occurrence as we age. Among the changes is a reduction in total body protein, which contributes to impaired wound healing, skin elasticity and ability to fight infection.
In younger adults, protein tissue accounts for 30% of whole-body protein turnover. It declines to 20% or less by the age of 70. Elderly adults are less responsive to the anabolic stimulus of low doses of amino acid intake than younger individuals. However, this lack of response can be overcome with higher levels of protein or EAAs.
Experts in the field of protein and aging recommend a protein intake between 1.2 and 2.0 grams per kilogram of body weight. Older adults can also support protein intake with EAA supplementation, especially leucine. Studies demonstrate maximal stimulation of MPS with 15 grams of EEAs. Read more about protein consumption and the elderly in a study by Baum, Kim and Wolfe (2016).
There is no one-size-fits-all approach for nutrition, including protein requirements and sources. Your needs will be dictated by goals, activity levels, stage of life, and food preferences, among others. The guidelines I have given here can serve as a starting point and then be adjusted based on the outcome.
If you would like to learn more about my nutrition coaching services, send me an email.