Optimizing Protein: How Much Is Enough?

Do you think you eat enough protein to optimize physical and metabolic health?

Most people will answer yes, but surveys show that the vast majority of people are not eating enough protein. Due to a combination of misconceptions about protein and suboptimal eating habits, many people are coming up short when it comes to protein intake.

This article will review the state of the research on how protein impacts body composition and health and provide recommendations for optimizing your protein intake.

Benefits of Protein

Ask your average person what they think of when they hear the word “protein” and they will probably reply “muscle.” It’s true that eating protein stimulates protein synthesis in the body, helping to build muscle when combined with weight training. But protein has many other benefits including the following:

• Improves bone mineral density.
• Provides the building blocks to make neurotransmitters that regulate mood.
• Blunts hunger to prevent overeating and fat gain.
• Improves deep sleep by balancing brain chemistry.
• Lowers blood pressure by improving the function of blood vessels.
• Improves biomarkers associated with longevity and quality of life.

An argument could be made that protein is the most important macronutrient for optimizing health and function over the lifespan. It’s also vital for athletes who want to enhance physical performance.

How Does The Body Use Protein?

Eating the right amount of protein serves several purposes in the body:

• First, it is burned for energy, especially during endurance exercise.
• Second, protein is used to make neurotransmitters.
• Finally, protein stimulates protein synthesis in muscle, connective tissue, and bone.

Protein synthesis is critical because the body is constantly in a fluctuating state of muscle loss and gain. With fasting or a meal that lacks protein, your muscles will be in a state of “breakdown.” Any time you provide the building blocks for muscle by eating protein, it’s a good thing. Protein intake puts you closer to a state of positive protein balance, which allows for the growth of muscle over time.

How Much Protein Can Muscle Use?

The U.S. RDA would like you to believe that all you need is a relatively small amount of protein daily, recommending that adults consume 0.8 g/kg of bodyweight (0.36 gram per pound of body weight). But this amount doesn’t prevent protein breakdown, let alone come close maximizing protein synthesis in any population. It’s also insufficient for optimizing satiety or preventing overeating.

A wealth of research has come to the following conclusions regarding optimizing protein synthesis:

For maximal protein synthesis in the absence of exercise, younger adults need between 0.24-0.3 g/kg of protein per meal. This equals 17.5 to 21 grams per meal for a 160-pound person.

Older adults (over 50) suffer from something known as “anabolic resistance,” which means that they need more protein per meal to maximize protein synthesis. Scientists recommend 0.4 g/kg of protein per meal, which works out to 28 grams for a 160-pound adult.

How Much Total Protein Does The Body Need?

Total protein intake is also key: Studies recommend a minimum of 1.6 g/kg (0.73 g/pound) of protein over the course of the day to optimize protein synthesis. For a 160-pound person this equals 116 grams total. Athletes and people involved in resistance training may benefit from going as high as 2.4 g/kg/day.

Protein should be spread out over meals at strategic intervals. By repeatedly stimulating protein synthesis every few hours, you can prevent the body from shifting into a state of protein breakdown. One study found protein synthesis to be significantly higher in response to eating 20 grams every four hours over the course of the day compared to a smaller dose of 10 g every 1.5 h or a larger dose of 40 g every 6 hours.

Strength Training Makes Everything Better

Protein intake is one of two factors that impact muscle mass. Resistance exercise is the other. Strength training with weights sensitizes the muscles to the amino acid building blocks in protein. Some experts theorize that exercise increases the capacity to use amino acids.

Because resistance exercise primes muscle to use protein, a large dose of protein is recommended after training. Previously, 20 grams of protein was thought to optimize protein synthesis, but more recent studies show that as high as 40 grams of protein may be ideal. One study found a 19 percent increase in protein synthesis with 40 g compared to 20 g. Scientists conclude that 30 grams is the sweet spot for younger athletes, whereas older adults involved in resistance training will likely benefit from the 40 gram dose.

How Much Protein When Trying to Lose Fat?

Protein intake should be the cornerstone of any weight loss plan due to its ability to blunt hunger. Protein intake also shifts the body to lose fat rather than muscle. For overweight individuals, about 25 percent of lost weight is muscle mass. The effect is greater for leaner individuals, who may find that 50 to 60 percent of weight lost is from muscle. Higher protein intake can prevent this.

In one study, when protein intake was 1.6 g/kg during a diet and exercise program that cut 40 percent of calories, muscle was better preserved compared to a diet that provided the U.S. RDA of 0.8 g/kg.

Adding strength training into the mix can halt lean mass losses even in leaner subjects. Muscle mass increased in lean individuals who went on a 4-week energy-restricted diet and resistance trained 6 days a week while consuming 2.4 g/kg of protein. A meta-analysis concluded that lean individuals should consume protein in the range of 1.6 to 2.4 g/kg a day and in some cases as high as 3 g/kg a day when cutting to prevent body mass loss.

How Important Is Protein Quality?

Plant-based marketers are one of several groups incorrectly saying that proteins made from grains, nuts, and seeds are good sources of protein. In fact, these proteins have low biological value and they lack essential amino acids necessary for stimulating protein synthesis.

This is why scientists always use whey protein when testing the effect of different training protocols on protein synthesis. Derived from milk, whey protein contains all the essential amino acids like other animal proteins. It contains plenty of leucine, which is the most important amino acid for stimulating protein synthesis. Other foods with high biological protein value include eggs, beef, poultry, and fish.

Because the body can’t use vegetable-derived protein sources as efficiently as animal proteins, a higher total protein intake is needed to achieve the same physiological effects. Simply, you may need to bump your daily protein goal up from recommended numbers if you’re getting your protein from vegetarian sources.

Are Carbs Necessary?

One of the hard-to-get-rid-of myths about protein synthesis is that you need to consume carbs post-workout in order to maximize protein synthesis. The theory goes that carbs spike insulin, which can improve protein balance when amino acids are low in the blood stream. However, protein alone raises insulin, and research shows that taking carbs with protein does not enhance the anabolic effect, nor does it contribute to greater muscle building. Therefore, for people interested in losing fat or who need to be careful about blood sugar spikes, there’s no drawback to taking protein by itself.

Take Aways

Protein is the most important macronutrient for optimizing health and function over the lifespan. It’s also vital for athletes who want to enhance physical performance.

Older adults require more protein per meal to get the same muscle building effect as younger adults. Experts recommend 0.4 g/kg of protein per meal for older adults and 0.24 to 0.3 g/kg in youngsters.

Total protein intake may be the most important factor: A minimum of 1.6 g/kg of protein over the course of the day is recommended for older adults and anyone interested in maximizing lean body mass in the absence of exercise.

More research is needed, but it’s possible that resistance training increases the capacity for the body to use protein, meaning that athletes and individuals involved in resistance training may benefit from going as high as 2.4 g/kg of protein a day.

Timing of protein is the third important factor when it comes to nailing protein intake. Spreading protein out evenly over all your meals will yield better muscle building results than end-loading it at dinner, as most people do.

Protein can help with fat loss, reducing appetite and helping to preserve lean mass. A daily intake ranging from 1.6 to 3.0 g/kg is recommended in conjunction with strength training.

Animal proteins are the highest quality proteins. When eating plant-based proteins, you may need to bump your daily protein goal up from recommended numbers to optimize protein synthesis and muscle development.