by Charles Poliquin Iron Magazine
There’s a lot of confusion about protein.
Do you know how much protein you should be eating per meal?
What about over the course of the day?
This article will help you figure out how much protein to eat by answering six common questions people have about how the body uses protein.
#1: How much protein do you need to maximally trigger protein synthesis?
A lot of people think the body can only “absorb” 20 to 30 grams of protein at a time. This is not technically true because as we’ll see in #4, the body absorbs all the protein you eat.
It is true that 20 to 30 grams is the amount of protein that will maximally trigger protein synthesis.
So, these are two different things, which are getting confused:
1) Stimulating protein synthesis, and
2) The body absorbing the protein.
An example of the numerous studies investigating the amount of protein needed to maximally trigger protein synthesis is a 2009 study by Symons that found that a meal containing 30 grams of lean beef increased muscle protein synthesis by about 50 percent in both young and old volunteers. A larger dose of 90 grams of beef didn’t further increase protein synthesis.
This means that when it comes to eating whole foods like a quarter-pound of beef or 3 ounces of chicken, you’d get the same increase in protein synthesis as if you ate three times that.
#2: How much protein do you need from a supplement following strength training?
The research also consistently shows that 20 to 30 grams of protein after training will maximally stimulate protein synthesis. Egg, whey, and casein protein (among others) have all been tested.
For instance, when a dose of 0, 5, 10, 20, and 40 grams of whole egg protein were compared, 20 grams was enough to maximally trigger protein synthesis. There was no added benefit from 40 grams.
It’s over the course of the day that a greater protein intake becomes important because this sustains protein synthesis and may accelerate recovery. For example, a 2012 study by Moore found that taking four 20-gram doses spaced every 3 hours produced a better balance between protein breakdown and synthesis after the workout than consuming 10 grams every 1.5 hours, or 40 grams immediately post-workout and at 6 hours after training.
First, 10 grams is not a large enough dose to offset protein breakdown or optimally rebuild muscle and lean tissue after training, even if it’s taken in a pulse format every 1.5 hours. You need 20 grams.
Second, a large total protein dose is necessary over the course of a day, but a 20-gram dose is adequate per feeding or “meal.” Naturally, you don’t have to take four doses of whey protein. You could take one dose and get the rest of your protein from food, spacing it out every few hours.
Third, it’s recommended that the average person interested in body composition or fat loss only use one dose of whey protein and then get the rest of their protein from whole foods. Or get all of your protein from whole foods if you prefer.
It’s really body builders and athletes who are aggressively trying to put on muscle or accelerate recovery for intense, frequent training who may benefit from dosing with whey.
#3: Which protein source is best?
When it comes to protein supplements, whey is the best protein you can use because it has a better amino acid profile. It triggers protein synthesis more and it’s use with training leads to greater lean muscle mass gains over the long term. It also contains more leucine, the most important amino acid for triggering protein synthesis.
Still, there have been rumors that casein protein should be taken with whey for greater gains because casein is more slowly digested. This claim doesn’t hold up well to scrutiny because casein is simply an inferior protein source and there are better ways of sustaining protein synthesis over the course of a day than taking casein, such as eating whole protein every few hours.
First, some people are allergic to casein, which could be due to the fact that human milk contains a very low percentage of casein compared to whey (10 percent versus 90). Or it could be that casein is more of a problem for people who eat gluten because gluten can increase risk of leaky gut.
Second, research shows there are therapeutic health benefits of whey protein. For example, whey protein has been shown to improve metabolic health despite triggering a large insulin response. It is even being tested as a supplement that can manage type 2 diabetes.
#4: What happens when you eat more than 20 to 30 grams of protein?
So, 20 to 30 grams of protein is all you need to trigger protein synthesis, and we already have a clue that it’s better to spread protein intake out over the course of day than eat a huge amount all at once.
But what happens if you ignore the research and go ahead and take 40 to 50 grams of protein every day with training?
Once protein synthesis is maximally stimulated, the rest of the protein is used for other purposes such as building enzymes, hormones, neurotransmitters, immune factors, and so on.
Some of it stored as amino acids in muscle tissue as a reserve for times when dietary amino acid stores are low. If your body is deprived of protein for a period, it uses these stored amino acids for energy or synthesis of other essential proteins.
After those priorities are taken care of, the body can use protein for energy. It turns it into glucose via the liver, which you can burn. This process leads to the conversion of nitrogen from the amino acids into ammonia, which you excrete in urine.
It’s this elimination of ammonia that appears to be the reason that people incorrectly say that “extra protein is excreted through the urine.”
That’s not true since your body has already absorbed, metabolized, and “used” the protein before the ammonia byproduct is eliminated. One thing to know about ammonia is that if levels in the blood get too high, your pH will become more acidic, which the body will balance out with calcium reserves.
The other thing that will happen, especially if things aren’t working right in the body, is you will eliminate the overload of ammonia in sweat. If your sweat has an ammonia odor, you should dial back your protein intake.
#5: Can excess protein be stored as fat?
Because excess protein can be turned into glucose and used as energy, it can technically be stored as fat. However, it’s very unlikely that a high protein intake will make you fat.
You always have to think about these things in the context of other factors including the following:
1) your total calorie intake
2) the proportion of carbs and protein you eat
3) your body fat and lean mass percentages
4) your physical activity level
5) your age
For example, if you are sedentary, have a high protein intake (say 1.6 to 2 g/kg of body weight), but you also have a high carb and total calorie intake, you might gain fat.
But, if we assume that “high-protein” means that protein is taking up a large proportion of your calories (20 to 30 percent), your calorie intake isn’t excessive, and you are active, you won’t gain fat. Here’s why:
• Protein doesn’t cause large spikes in blood sugar and it tends to improve insulin sensitivity. It also leads to better balance of other hormones like leptin and ghrelin that help you avoid hunger.
• Protein boosts your metabolism because it costs the body more calories to process protein than it does carbs or fat.
• Because protein triggers protein synthesis, it builds lean mass, which sustains the amount of calories you burn at rest.
#6: How much protein should you eat?
Research into the issue has concluded that 0.82 g/lb or 1.8 g/kg of body weight of protein is the amount to be maximally beneficial for body composition. This doesn’t mean that if you eat more you’ll gain fat, but that more is unlikely to give you additional gains in lean mass, and from a research standpoint, there’s no evidence of a metabolic advantage.
Obviously, not everyone is the same and it’s possible that some people may truly experience body composition benefits from eating more protein. In practice, 1 to 2 grams of protein per pound of body weight of protein is useful for fat loss when on a low-carb diet, especially if you are training hard and need to improve insulin sensitivity. The high protein dose is beneficial because it reduces hunger and supplies calories to aid in recovery from training when carbs are restricted.
There is some evidence that “cycling” your protein intake can lead to greater gains in muscle mass with strength training. One review found that when trainees had their protein intake increased by at least 60 percent over normal during a hypertrophy-workout phase, they had superior gains.
This appears to be most effective if your protein intake is fairly low to begin with. For example, if you’re eating 1 g/kg of protein, you could easily bump that up to 1.6 or 1.8 g/kg and expect to experience greater growth with training than if you just increased to 1.3 g/kg because the “change” is at least 60 percent. But, if you’re already at 2g/kg, you have little room to increase protein much without serious force feeding.
Finally, the rate at which you oxidize or “burn” protein for energy or use it for protein synthesis will vary depending on how much you eat and how much you train. The body is highly adaptive and its goal is to work as efficiently as possible.
When you decrease protein intake, your body “uses” more of it for protein synthesis and related processes, but if you eat more, the percentage of protein utilization decreases. Extra goes into gluconeogenesis.
Here’s the bottom line:
• If you want to lose fat, protein is your friend. Shoot for at least 1.6 g/kg a day of protein. Make sure your total calories and proportion of carbs is ideal for your physical activity and unique genes.
• If you want to put on muscle, protein is king. Shoot for at least 1.6 g/kg of protein a day and be sure to spread your intake out over the course of the day.
Consuming 20 to 30 grams of protein at once is all you need to stimulate protein synthesis, but that doesn’t mean you can’t eat more if you want to. There’s just no muscle building advantage.
• See our list of the Best Protein Foods For Fat Loss and Body Composition here!
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