There are so many tips and opinions available about how much protein we should be consuming. Those information can be summarize into "we need to eat more protein", "too much protein will make you fat", "our body doesn't digest more than 30g of protein at a time", and so on.
From a science perspective, depending on what you are wanting to accomplish, protein intake can vary from 1.2g/kg of your body weight (.54g/lb) to 3.3g/kg (1.5g/lb).
Something important to keep in mind is that although we talk in terms of protein requirement, however, we don’t really have a protein requirement. We do have amino acids requirement, especially with 9 essential amino acids. There are 20 amino acids and 11 we can make in our body and 9 must come from food source, hence the name essential amino acids. These 9 essential amino acids are building blocks to new protein. For example, leucine and mTOR, arginine and nitric oxide, lysine and carnitine, and so on. Because this is somewhat complicated, we summarize as protein requirements.
Protein or amino acids are important in the creation of not just muscle but also hormones and enzymes as well. For example, for our body to create insulin, it needs 51 amino acids. Myosin, which is an important fiber in muscle and its motion, requires a thousand amino acids.
What does this all mean? It means that we need to be mindful of why we are consuming protein and understanding what sources have fair number of amino acids.
Sources of Protein
When selecting protein sources, you should be mindful of their /quality. Protein quality is determined by the availability of 9 essential amino acids and amount of each that is in the food.
This information can be found in amino acid score chart called DIAAS and PDCAAS. The score is determined by how many different essential amino acids are in food sources and their amount. It is not a definite but a good place to check the quality of the protein sources.
It is important to understand that when food source is consumed in variety per meal, it can complement each other and may be able to consume what essential amino acids each may be lacking. For example, chicken breast is high in amino acid score but does lack in amino acids called tryptophan. Cooked rice is lower in amino acid score but lack in amino acids called lysine but contains tryptophan. If you can prepare chicken breast served with rice you can complete the essential amino acids requirement.
Here are some of the food sources that are high in protein with amino acid score according to DIAAS.
Food Source (per 100g) – amino acid score; protein (g)
Chicken Breast – 100; 23g
Egg (hard boiled) – 113; 6.3g
Beef – 111; 20g
Almonds – 37; 21g
Whole milk – 114; 3.2g
Soy (edamame cooked) – 91.5; 12g
Pea (Raw) – 91.5; 5.4g
Rice (white cooked) – 59; 2.7g
Protein Supplements
In comparison, the study for protein supplements between whey, soy and casein proteins whey protein seems to be the ideal form of protein source in muscle and strength building. Whey protein and casein are made from milk. Whey protein comes with different form depending on how much lactose has been removed from milk. Whey protein concentrates have a ratio of 7:3 between protein and lactose. When it comes to whey protein isolates this ratio will be 9:1. If you are lactose intolerant, you can use whey protein isolate or collagen peptide.
The benefit of whey protein is it has high concentration of essential amino acids, especially BCAA (branched chain amino acids) and another form of amino acid called cysteine. BCAA promotes anabolic response to muscles which helps recover and build muscle after physical activities. Whey protein also has important benefits for your immune system. Amino acid cysteine promotes glutathione which is antioxidants and free-radical scavenger. Cysteine also has benefits in skin health. Whey protein also works as hunger suppressant. So, when you take whey protein in the morning you can feel full until lunch time.
Those who have allergic reaction to whey or those who follow vegan diet, soy, pea, hemp, and rice protein can be an option. Especially soy protein does have high concentration of BCAA and glutamine. Soy protein is more arginine compared with whey protein, which helps dilate blood vessels and improve blood flow. However, soy protein does have trypsin inhibitor which inhibits protein breakdown. When protein enters the body, it needs to break down into amino acid for absorption. With trypsin inhibitor, this process can slow down. This is one of the reason people are concerned about using soy products. However, the trypsin inhibitor is weak against heat and fermentation so fermented soy and tofu does not have this issue though soy milk does. So, it is not good advice to mix protein with soy milk.
Though soy protein can slow down protein absorption, this can be beneficial. For example, for those who are on weight loss program or want to use protein before going to bed. Slow-release protein can keep the amino acid level steady for extended period. However, when the body needs protein supply immediately, such as after workout, may want to use whey protein.
What is your goal?
When setting your protein amount and what type of protein source you want, you need to consider the purpose of your protein intake. Are you planning to increase muscle mass or do you want to maintain muscle mass while losing fat? Some people just want to be in good health and not thinking about gaining muscle or losing fat.
What is your activity level?
Protein intake can vary from your activity level. If you have a sedentary lifestyle then you probably do not need as much protein as those who are athletes who are trying to increase strength during off season.
What is your current condition?
The condition I am referring to is whether you are healthy body weight, overweight, pregnant and so on. If you are overweight or obese, you want to increase your protein, however, it is not as much as you want. If you have issues with liver and kidneys or on various medications, you may want to consult with your physician and dieticians (not nutritionists) on what you can do about protein intake.
Let's talk about how much protein a person will need.
If you have a sedentary lifestyle where you are in front of a computer at work, you should aim for at least 0.54g/lb of your body weight. Of course, as your activity level goes up, such as start working out or hiking over the weekend then this number should increase.
For healthy individuals who are active and want to maintain their lean muscle mass, they should be aiming for 0.64g/lb to 0.73g/lb of protein per day.
If you are healthy individuals who are active and wish to increase muscle mass, then the amount of protein would be from 0.64g/lb to 1.09g/lb.
If you are healthy individuals who want to lose fat, you should aim for 0.82g/lb to 1.24g/lb.
If you are obese or overweight, regardless of your activity level, you should aim for 0.54g/lb to 0.68g/lb. The weight you should be calculating is your current body weight and do not need to be calculating with your ideal body weight.
The amount of protein illustrated above seems to work for older adults (50-year-old+).
Pregnant women may need 0.77g/lb of protein to support both fetus and them.
Case Study 1
Let's say we've got 200lb overweight individual. This person should be consuming anywhere between 108g to 136g of protein a day. One of the reasons to keep the protein intake not too high for obese or overweight individuals is because of insulin. In protein there is an amino acid called alanine, which does promote secretion of insulin. Although insulin spikes are not significant compared with carbohydrates, those who are overweight or obese already have insulin in bloodstream to take care of. Therefore, along with minimizing carbohydrate intake is often suggested.
Case Study 2
If 120lb individual wants to build muscle, their protein intake can range from 76.8 g to 130.8 g per day.
Case Study 3
If 140lb an individual who is 65 wants to maintain muscle but lose fat should be consuming 114.8 g to 173.6 g
Trial and Error
Although these numbers are all through scientific findings, these numbers are guided. What work for you should be determined by trial and error based on the number suggested above.
Start with working towards the amount of protein you should be consuming from numbers above for 4-8 weeks. From there, see how you want to adjust according to what you are feeling and experiencing. Adjust your protein intake based on what outcome you are experiencing.
Kota Shimada
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