Are You Getting Enough Protein to Reach Your Fitness Goals?

The first step to reaching any fitness goal is a healthy diet, of which protein is a vital part. Getting enough protein is essential for building and maintaining muscle. Plus, it helps with weight loss! Here we'll discuss how to determine how much protein you really need to reach your fitness goals. 

How to Determine Your Specific Protein Needs

Eggs and avocado on english muffin
Jeff Wasserman/Stocksy United

The amount of protein you need is based on your age, weight, and health goals. In the United States, the recommended daily allowance (RDA) for protein is 0.8 grams per kilogram of bodyweight (0.36 g/lb/day). While this is adequate for sedentary adults who want to maintain muscle mass without losing or gaining weight, recent research suggests that seniors and people with fitness goals may benefit from more.

Seniors (>65 years) are especially susceptible to age-related muscle loss. With regard to proteins, healthy seniors should consume at least 1.0–1.2 g/kg/day (0.45–0.54 g/lb/day), while sick or injured seniors should consume at least 1.2–1.5 g/kg/day (0.54–0.68 g/lb/day).

Physically active people (including seniors) should aim for an even higher protein intake, as it has been shown to improve recovery from exercise, preserve lean mass, and bolster fat loss. Both 1.2–1.7 g/kg/day (0.54–0.77 g/lb/day) and 1.4–2.0 g/kg/day (0.64–0.91 g/lb/day) have been recommended, with one study noting increased benefits from 2.4 g/kg/day (compared to 1.2 g/kg/day) in men exercising under a 40 percent calorie deficit.

If you have a BMI of more than 30, you may want to calculate your protein requirements based on your goal bodyweight rather than your current bodyweight, so as to avoid overeating.

How Protein Is Used for Energy and Why High-Protein Doesn't Mean Harmful

Protein can be converted into glucose, the sugar your body uses for energy. This occurs at a higher rate during a low-carbohydrate diet and slows down when carbohydrates are plentiful. Physical activity also increases the rate of this process, with endurance exercise having a higher effect than anaerobic activity.

Proteins are composed of amino acids. The more overall calories the body has to work with, the more efficiently it uses protein. To wit: Fewer amino acids are used for energy and more to build muscle tissue.

Why High-Protein Diets Aren't Harmful

According to a 2001 statement from the American Heart Association, high-protein diets are dangerous because they “do not provide the variety of foods needed to adequately meet nutritional needs. Individuals who follow these diets are therefore at risk for compromised vitamin and mineral intake, as well as potential cardiac, renal, bone, and liver abnormalities overall.”

Yet, while protein-restricted diets are generally recommended for people with kidney or liver damage, there is little scientific evidence to support the hypothesis that a high-protein diet is harmful to the heart or liver, kidneys, or bones of a healthy person.

Ideal Sources of Protein

Fish, meat and eggs are ideal sources of protein.

Proteins rich in all nine essential amino acids (EAA) are called complete proteins. They are found mostly in animal products (primarily meat, fish, dairy, and eggs), but also in some plant products (notably soy, quinoa, buckwheat, and chia seeds). If you buy a supplement, choose one that functions as a complete protein source. When you buy whole foods, however, don’t restrict yourself, as different proteins from different foods will bring you all the amino acids you need. For instance, while pea and rice proteins are “incomplete” separately, their combination can make for a complete protein.

Protein sources do matter in the context of your overall diet, though. To keep calorie count low, or to free up some calories for a guilt-free indulgence, you might want to prioritize lean protein sources—such as soy, chicken, egg white, or warm-water fish (such as tilapia and bass). On the other hand, fatty fish (such as bluefin tuna and salmon) are rich in omega-3 fatty acids, of which we seldom get enough, so leaner is not always better.

Supplementing Protein Is Optional

Before considering supplementing protein, evaluate your diet to determine if you can swap out certain foods to meet your protein requirements. Remember, getting protein through whole foods provides benefits that supplementation cannot. For example, high-protein beans like soybeans or lupin beans also contain fiber that can benefit your microbiome and help you feel full. As for unprocessed whole meats, they often pack a good amount of vitamins and minerals lacking in most protein supplements.

If your current diet doesn’t provide you with enough protein to reach your daily goal, and if you cannot make more dietary changes, then protein powders are a cheap and convenient way to increase your daily protein intake.

Whey and casein powders are both derived from milk protein (which is 20 percent whey and 80 percent casein). If you are neither lactose intolerant nor vegan, whey is an easy choice, for it is cheap and very anabolic (good for building muscle). Casein is more expensive, less anabolic, but more anti-catabolic (good for preserving muscle). Since casein digests slowly, it is often seen as the ideal protein to consume before going to sleep.

Vegans can turn to soy, a complete protein, or to a 70:30 pea:rice protein blend, which is seen as the vegan alternative to whey due to similar amino acid profiles. Depending on processing techniques, the estrogenic isoflavone content can be greater in soy protein isolate than in soy protein concentrate, but it is still too small to elicit any significant hormonal response when as much as 200g of soy protein isolate is consumed per day.

Other supplementation options for conserving muscle mass during caloric restriction include leucine and β-hydroxy β-methylbutyrate (HMB). Leucine is the primary anabolic amino acid in protein; it is responsible for signaling muscle tissues to grow. Some 5 percent of leucine is metabolized into HMB. For anti-catabolic purposes (i.e. to hinder muscle breakdown), 1 g of HMB is equal to about 20g of leucine. However, for anabolic purposes (i.e. to promote muscle growth), leucine seems to have a slight upper hand on a gram-per-gram basis.

Don't Overthink Protein

Getting enough protein shouldn’t be an overwhelming challenge. Most concerns regarding protein supplementation—such as finding the right kind of protein to take and figuring out when to take it—stem from overthinking. As long as you exercise regularly, sleep well, and eat enough protein (through whole foods and, if you wish, the occasional supplement), your body will have the tools it needs to build muscle and keep you healthy.

Research has shown high-protein diets to be safe for healthy people. People with liver or kidney issues should talk to their doctor about their protein intake before making dietary changes or supplementing protein.

If you’re intimidated by the amount of daily protein you need for your health and fitness goals, start by eating your favorite protein-rich foods while occasionally exploring a new option. Food variety will make it easier to get enough protein without stressing about it.


Bauer J, et alEvidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study GroupJ Am Med Dir Assoc (2013)

Campbell B, et alInternational Society of Sports Nutrition position stand: protein and exerciseJ Int Soc Sports Nutr (2007)

Deutz NE, et alProtein intake and exercise for optimal muscle function with aging: recommendations from the ESPEN Expert GroupClin Nutr (2014)

Longland TM, et alHigher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trialAm J Clin Nutr (2016)

Morley JE, et alPrevalence, incidence, and clinical impact of sarcopenia: facts, numbers, and epidemiology — update 2014J Cachexia Sarcopenia Muscle (2014)

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