Protein is essential for virtually every one of yur cellular functions. Most people, when they think of protein, think of building muscles. There’s much more to protein than merely muscle.
You need protein for the structure, metabolic function, and regulation of all tissues and organs, including muscle. Every cell in your body is full of enzymes,which are proteins that control your metabolism.
Protein is also important for neurotransmitters which are responsible for mood and even your sleep. Your bones, your ligaments, your tendons, your liver, your brain, skin, and fingernails are all built from proteins.
Why do we need protein?
To truly understand protein, we must first understand that proteins are built from amino acids and these amino acids are the foundation of how we will build your diet. By getting your protein intake correct, you will get your amino acid requirements correct. There are 20 of these amino acids and some sources of protein you eat have more of these amino acids with a better balance of the individual amino acids than others.
- Protein is used for everything but it is especially critical for maintaining a healthy muscle mass which is increasingly difficult to maintain as we age as we lose 1% of our muscle every year we age past 40.
- Maintaining our muscle mass is a key indicator of health and longevity. Lack of it makes fragile!!
Protein and muscle synthesis
Muscle is the organ of longevity. It functions beyond locomotion. Muscle is the foundation of your metabolism, helping to regulate blood sugar and blood lipids. It’s also an endocrine organ that secretes myokines, proteins that help regulate metabolism in all other tissues in the body. The stronger and healthier your muscles, the more carbohydrates and fat your body burns. It is your metabolic currency.
The nine indispensable or essential amino acids, defined as those that the body is unable to synthesise from simpler molecules, are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Cysteine and tyrosine can partly replace methionine and phenylalanine, respectively. Under certain extreme physiological conditions such as in prematurity or during some catabolic illnesses, the non-essential amino acids arginine, cysteine, glutamine, glycine, proline and tyrosine may be require in the diet. Under normal conditions, glutamine, glutamate or aspartate can supply arginine; methionine and serine can be converted to cysteine; glutaminic acid and ammonia can be converted to glutamine; serine or choline can supply glycine; glutamate can provide proline and phenylalanine can be converted to tyrosine. These amino acids are sometimes termed conditionally indispensable. Alanine, aspartic acid, asparagine, glutamic acid and serine are non-essential. The amino acids act as precursors for many coenzymes, hormones, nucleic acids and other molecules.
Proteins in the diet and the body are associated with a number of other vitamins and minerals and are more complex and variable than other energy sources such as fat and carbohydrate. The polypeptide chains that make up proteins are folded into three-dimensional structures that include helical regions and sheet-like structure due to interaction between the amino acids in the chain. The final shape of a mature protein often reflects its function and also interactions with other molecules. The protein’s structure may influence its digestibility.
The body of a 76 kg man contains about 12 kg of protein. Nearly half of this protein is present as skeletal muscle, while other structural tissues such as blood and skin contain about 15% (Lentner 1981). Myosin, actin, collagen and haemoglobin account for almost half of the body’s total protein content. Only 1% of the body’s store is labile (Waterlow 1969, Young et al 1968), so its availability as a reserve energy store, compared to body fat, is limited. Unlike carbohydrate and fats, the body does not maintain an energy storage form of protein.
Proteins are found in both animal and plant foods. The amino acid profile of animal proteins is closer to that of humans but all of the necessary amino acids can be provided in the amounts needed from plant sources. Certain proteins can cause allergic responses in some individuals notably milk, eggs, peanuts and soy in children and fish, shellfish, peanuts and tree nuts in adults.
Protein need per meal
In order to stimulate enough protein synthesis we need to get around 2.5grams of leucine in one meal. Imagine your muscles like car. You need some sort of key to be able to turn it on right? Enough leucine is the key for your muscles!
How does this translate into actual food?
Learn to design each meal around a targeted amount of high quality protein. I recommend three meals each day for most adults with a minimum of 30 grams of high quality protein to optimize muscle protein synthesis. But this recommendation is also goal dependent. If you’re trying to gain muscle, you can increase your intake to four meals. It’s more effective to increase your meal number than to eat more and more protein at a single meal. For example, if your protein target is 200 grams a day, and you already have three meals containing 40 grams of protein each, you should add an extra meal. There will be more on that later.
- Animal and plant proteins are needed in different amounts as plants don’t have the needed Amino-acids in the correct amounts.
- We need a minimum of 30grams of protein per meal.
There are two types of amino acids:
First, there are the essential amino acids. These come directly from our diet and we need a daily supply; and for some amino acids, a supply at each meal.
Then, we have nonessential amino acids. Our body produces these all on its own.
Since every individual has a different overall diet, all the similarities notwithstanding, there are two possible occurrences. The first is you are not getting enough protein. The other is you have no idea how much protein you’re actually getting in a day. For someone who isn’t as conscious of their diet, I usually find most people are a combination of the two.
They aren’t getting enough, and they have no idea how much they aren’t getting until they make an attempt to quantify it by tracking their intake.
On top of that, there are recommendations out there for protein intake. The current RDA (Recommended Dietary Allowance) for protein is set at 0.8 grams per kilogram of body mass (or about 0.36 grams per pound), which equates to only 72 grams of protein per day for a person weighing 200 lbs.
YOUR WEIGHT (kg) 0.8 RDA (IN GRAMS) FOR PROTEIN
Depending on your background and experience, this might sound absurdly low, relatively high, or you might feel neutral about it one way or the other. Nevertheless, the RDA exists for a reason, and that reason is to keep you alive. The RDA is defined as the bare minimum to simply exist. That is, the RDA is designed to prevent deficiencies and provide for basic tissue repair and not much more. It doesn’t take into account active lifestyles or people who want to protect muscle and longevity as we age. And I absolutely want you to optimize your current way of life, just as much as you do. In that regard, more protein will likely be more beneficial for you. It’s time to find out why.
You are now beginning to understand the vital role that protein plays and that it’s function is not limited to building new muscle. For instance, antibodies, used in an immune response, are made of proteins. When a toxin or otherwise foreign substance, known as an antigen, enters your body, your antibodies protect you by fighting them off.
In addition, many of your hormones, such as insulin, are made from proteins; and some like thyroid hormones, for example, are made from amino acids and transported by proteins. Thyroid hormones help to regulate your blood glucose and metabolic rate, and can impact growth hormone secretion and bone health.
Although all proteins are made of amino acids, not all proteins contain the correct balance of amino acids your body needs. Amino acids are the key to understanding protein needs, and I want to highlight three of them.
This is an essential amino acid found in high quality protein and is the key amino acid that drives muscle protein synthesis. It’s also a modulator of insulin signalling, a fuel for skeletal muscle, and a primary nitrogen donor for production of alanine and glutamine in skeletal muscle. In addition to muscle protein synthesis, Leucine also increases your ability to burn fatty acids.
That all sounds well and good, but think about how you age. As we age, our muscles become less efficient at the critical processes of repair and replacement of existing proteins. This aging process is called anabolic resistance. We succumb to what’s known as sarcopenia, the gradual loss of our muscle tissue.
However, the good news, we can blunt or mitigate this aging process with the right choices of exercise and protein. This means Leucine is even more important as we get older, and it’s also why our protein intake, both quantity and quality, should increase with age.
This protein, in addition to starting with the letter “L” and having two syllables and sounding kind of similar to Leucine, is another essential amino acid, which means you can only get it via your diet.
Lysine plays a large role in synthesizing proteins within your body. Not only that, Lysine is also responsible for the proteins specifically in your connective tissues, tendons, which connect a bone to a muscle, and ligaments, which connect bones to bones at a section called a joint. Your tendons and ligaments are composed of a structural protein called collagen, and Lysine is instrumental in collagen formation.
Lysine also forms the backbone of the molecule called carnitine essential to help your muscles burn fats for fuel. Lysine is extremely low in grain products and virtually absent in wheat. Breads and cereals are very poor-quality proteins.
Finally, we come to an amino acid that has more than two syllables and doesn’t start with the letter “L” but is just as important as its friends. Methionine is responsible for making creatine (that thing you might think is a steroid because weight lifters love it, but it really isn’t a steroid and is one of the most researched supplements around).
Methionine is important for the synthesis of carnitine, which is instrumental in fatty acid oxidation, and in the synthesis of another amino acid, cysteine, which leads to Glutathione, an antioxidant that helps with your immunity, and for production of DNA and taurine. Methionine also plays a role in detoxification of metals like lead and mercury as well as protecting the cell from pollutants due to its sulfur side groups.
Finally, methionine is always the first amino acid transcribed from mRNA so without enough of it, protein synthesis doesn’t even start. Methionine is often in low amounts in plant proteins, especially in legumes, lentils, and nuts.
Applying the info to your life
There are a couple of things I want you to notice.
First, there’s a lot of overlap among the foods listed. Because of that, I have a nifty three-way Venn diagram and right in the middle are all the foods that are rich in all three of these amino acids.
Second, you’ll notice the list has a few plant-based options, but the bulk of the foods listed are from animals, in some form or another. This is because animal sources are the highest in these particular amino acids. Now, it’s not impossible to get them on a vegetarian diet, especially if you are a lacto-ovo vegetarian. If you’re a lacto-ovo vegetarian, you still have the option to take in some high-quality animal protein sources from animals in the form of dairy and eggs.
It’s not impossible to get these essential amino acids in a vegan diet, though your options will be limited, and you will need to eat more total protein and more total calories to reach your goals. You may want to consider supplementing your diet to prevent a deficiency.
Before diving into the nuances of a balanced diet, you need to figure out how much you need to eat in a given day. It will be different for each of you, and there are a lot of equations out there on the internet to choose from. You are more than free to try those out, if you want. However, for the sake of ease, there’s a simple set of math equations everyone can follow to figure out their caloric and macronutrient needs.
Let’s assume a 90kg man. For him, we will use his body weight as our number in which we figure out his caloric intake. Before we do that, there are a few points of note about the calories within the food we eat. Specifically, every macronutrient has a calorie count per gram.
As we have established protein is critical for your muscle health, always begin your diet planning with decisions about protein. Our goal is 1.5 gram of protein per pound of body weight and every gram of protein produces 4 calories. So, for our 90 guy, should have around 150g of protein and that produces 600 calories.
How you decide to split carbs and fats that is for another chat.
More on Leucine
The minimum RDA for Leucine is only 2-3 g per day, but remember the RDA is designed simply to prevent deficiencies. You will want to shoot for at least 8 to 9 g per day for optimum muscle health with at least 2.5 g to 3.0 g at each meal.
The good news is once you start eating high quality protein and hitting your protein target every day, this will be easy to accomplish. To achieve your protein needs and optimize muscle protein synthesis, you need to eat a minimum of 30 grams of protein at each of your three meals per day. The origins of this 30 g number is not magic and it’s not related to the myth that your body can only use 30 g of protein in a meal. The 30 g is simply the amount of protein in an average meal that is required to get the minimum of 2.5 g of Leucine. The actual amount of Leucine differs in individual proteins.
Whey protein is a rich source of Leucine which is why it is a favourite of most body builders. Whey has about 11% Leucine, while meats have about 8.8%, soy about 7.8%, wheat 6.8% and quinoa 6.0%. So, you can get 3.0 g of Leucine with 27 g of whey protein or 34 g of beef protein, but it requires 38 g of soy, 44 g of wheat or 50 g of quinoa. For most meals, you’ll want your protein amount between 30-50 g, which is the sweet spot for muscle protein synthesis.