Optimal Protein Intake

By Rebecca Haight and Luke Serwinski

The importance of protein

Proteins are a part of every cell and tissue of the human body. They contain essential and non-essential amino acids essential in helping our bodies repair and grow. Simply put, only ingesting protein leads to muscle growth.  Carbs and fat won't grow muscle.  And, sad to say, even with the alcohol-induced effects of confidence and beer goggles, calories from alcohol won't cause muscle growth either.

Our bodies are constantly recycling proteins and the protein we consume through our diet can be used to replace broken down proteins and maintain balance. This is an on-going process which requires steady and sufficient protein feedings throughout the day.  Not just at one meal, not just on Tuesdays but at basically every meal.

RDA protein requirements

The Recommended Dietary Allowance (RDA) for protein is 0.8 grams of protein per kilogram of body weight. That amounts to about 0.35 grams per pound of body weight.

So, for instance, a person weighing 165 pounds should consume around 60 grams of protein a day (165x0.35), per RDA recommendations.

However, this RDA is only a representation of the amount of protein needed to meet your basic nutritional requirements. It’s not necessarily a recommendation on how much protein you should eat every day.

It’s actually a pretty low recommendation and most people, especially those who workout frequently, will need to consume more.

In fact, for a relatively active adult, just eating the RDA of protein would supply as little as 10% of his or her total daily calories.

Keep in mind; there are approximately four calories per gram of protein. So for the same 165-pound person in the previous example, the consumption of 60 grams of protein would only amount to the intake of about 240 calories.

The average American consumes closer to 16% of his or her daily calories in the form of protein, from both plant and animal sources.

There is a growing concern in the US, that we, as Americans, are consuming too much protein. And simply looking at the RDA for protein would lead many to believe they too are consuming protein in total excess. Many health professionals, however, are expressing just the opposite. Reports show many Americans are consuming too little protein, not too much. In fact, multiple reports contend, we should be consuming up to twice the RDA of protein.

New research suggests protein should make up 15% to 25% of total daily calories, although it could be above or below this range depending on your age, sex, and activity level.

That being said, there are a lot of false claims out there regarding recommended protein intake for those looking to gain muscle mass.

Latest research findings

For starters, there is a common myth that protein intakes above 1.8g/kg of total body weight (a full gram above the RDA) will help dieters maintain muscle mass. However, this claim does not have strong supporting evidence. Even if protein intakes above 1.8g/kg does assist lean mass maintenance, it probably doesn’t help everyone equally due to individual variance.

Of all the studies comparing higher versus lower protein intakes in people performing resistance training, 80% of them don’t show a significant difference favoring higher or lower protein intakes.

That being said, a new study examining the protein requirements of bodybuilders found that, on average, 1.7g of protein per kilogram of total body mass was the requirement on off days from training. They speculated it might be higher on training days. However, the same study acknowledged that some individuals have higher protein needs than others. Keeping that in mind, 2.2g/kg was the suggested guideline to avoid many individuals falling below their optimal intake.

Another study pitted very high protein intakes (3-4.4g/kg) against “normal” high intakes (1.8-2.2g/kg). Collective results found that less fat mass was gained in the very high protein groups compared to the semi-high protein groups, even when the subjects attempted to follow a caloric surplus. This implies that protein intakes above traditionally recommended ranges could possibly be useful due to their effects on total daily energy expenditure (TDEE) and satiety.

In fact, a separate dieting study found a protein intake of 2.4g/kg of total body weight was more effective for promoting fat loss and lean body mass (LBM) gain compared to 1.2g/kg during a 4-week dieting period in detrained, overweight men.

Based on findings from all these studies, 0.8-1g/lb (1.8-2.2g/kg) is probably the highest intake you’ll benefit from in terms of enhancing strength or mass gains when you’re not in a deficit.

In terms of dieting, its still unclear whether you’d benefit from an intake higher than 1.8-2.2g/kg for muscle retention. However, there probably are some benefits in terms of satiety and potentially mood.

But be wary of going too high, as excess protein can displace your caloric allotment for carbs and fat. But more on that below!

How protein converts to fat (hint: it basically doesn't)

Rant from Luke:

When you consume more protein than your body needs, the excess converted by the liver into mostly glucose and ketones.  But the process of then converting THAT to body fat is not efficient and thus rarely would excess protein be converted to body fat.  Since protein is so satiating that if you approached a situation where you just ate a ridiculous amount of daily protein, the satiating effects would likely cause you to still eat at maintenance or less.

The metabolic pathway is not very efficient for turning protein into body fat.  Of the two main by-products of excess protein ingestion, glucose is (despite popular belief) not efficiently converted to body fat and ketone bodies such as beta-hydroxybutyrate have powerful appetite suppressing effects.

In fact, dietary fat is THE most efficiently converted to body fat.  So in a case where excess protein is ingested you have the triple whammy of protein being very satiating, excess glucose not being converted efficiently to fat (most likely burned off as energy) and ketone bodies suppressing appetite further.

The main driver of fat gain is, as always, excess calories.  So if you over eat you will gain weight.  Excess fat is the most easily converted to body fat, with carbohydrates next and protein dead last.  In the event of an extremely high protein diet, it will be very hard to over-eat, meaning you'll likely still be at energy balance or less.

These reasons are exactly why high-protein diets are recommended by so many informed nutrition coaches.  You maximize protein synthesis (muscle gain), suppress appetite, stabilize blood sugar and reduce the risk of ingesting excess calories.  So why on earth would you eat the RDA of 0.8 g/kg when it is likely too low to maximize all the benefits above?

To drive a final nail in the coffin of the low-protein debate, in a study conducted by George Bray in 2012 took subjects and over-fed them by 1000 calories per day.  In three groups of 5%, 15% or 25% protein, all groups gained body weight to a similar degree.  But the 25% protein group gained the most muscle as a percentage of their weight gain.  So we can see that excess calories are the major driver of weight gain while higher protein drives lean muscle gain.  So even when over-eating, ingesting more protein will likely cause a higher percentage of weight gain from muscle than fat.

And, like we said above, f you ingested an even higher protein diet (25% isn't THAT high), it would probably keep you so full it would be hard to over-eat.

Enough said.

Sources:

“ACSM | Brochures.” American College of Sports Medicine, www.acsm.org/public-information/brochures.

Campbell, Meg. “Can Protein Turn Into Fat?” LIVESTRONG.COM, Leaf Group, 3 Oct. 2017, www.livestrong.com/article/477319-can-protein-turn-into-fat/.

Helms, Eric, et al. “Reflecting on Five Years Studying Protein (by Eric Helms).” Stronger by Science, 20 May 2017, www.strongerbyscience.com/reflecting-on-five-years-studying-protein/.

Pendick, Daniel. “How Much Protein Do You Need Every Day?” Harvard Health Blog, 20 Oct. 2017, www.health.harvard.edu/blog/how-much-protein-do-you-need-every-day-201506188096.