What is protein?
Proteins are macronutrients that contribute to the renewal and construction of muscles, appendages (hair, fur, and nails), bone matrix, and skin. "Amino acids are the pearls of a necklace that form protein."
In fact, a protein is a combination of several amino acids. These are the building blocks that make up proteins. There are 20 amino acids in total, 9 of which are considered essential. These cannot be synthesized by the body, so they must be obtained from your diet.
What are the 9 essential amino acids?
- Valine
- Isoleucine
- Leucine
- Histidine
- Tryptophan
- Methionine
- Phenylalanine
- Lysine
- Threonine
- Structural role: This is their fundamental role. Proteins make up a very large number of structural elements in our body, such as cell membranes, collagen, connective tissue, bones, muscle mass, etc.
- Catalytic role: Many reactions take place every second in our bodies. It is proteins, in the form of enzymes, that ensure the proper functioning of these reactions, which are important for our health: digestion, nutrient absorption, energy production, etc.
- Role in muscle contraction: Proteins make up the fibers that make up muscle. Shortening these fibers allows muscle contraction.
- Role in the transport of molecules in the blood: for example, hemoglobin is a protein that allows the transport of oxygen in the blood while transferrin transports iron. There are many other transporters.
- Protective role of the immune system: antibodies are proteins that will detect all substances foreign to the body (antigens) and trigger the mechanisms for their elimination.
- Regulatory role of the endocrine system: Many hormones, such as insulin, which is involved in regulating blood sugar, are proteins. Hormones can be synthesized by different organs to ensure a regulatory function of our body's homeostasis (they keep the body in a stable and viable state).
Energy role: Proteins play a minor role in energy. In fact, if there is a lack of energy-producing macronutrients such as lipids or carbohydrates, proteins can be broken down into energy. 1 gram of protein provides 4 kcal, just like carbohydrates.
What foods are rich in protein?
There are two food sources of protein:
Animal proteins.
They contain all the essential amino acids in large quantities. They are found in all meats (red meats, chicken, turkey, etc.), fish (salmon, tuna, etc.), eggs, but also in dairy products (milk, cheese, yogurt).
Animal protein content per 100 grams.
- Cheese: 22 g
- Meat, fish, egg: 18 g
- Fresh cheese: 8 g
- Dairy: 6 g
- Yogurt: 4 g
- Milk: 3.5 g
Plant proteins.
Cereals (oats, rice, wheat, etc.) and legumes (lentils, peas, soy, etc.) are excellent sources of plant-based protein, although they may be deficient in certain essential amino acids.
- Lentils: 25.4 g
- Split peas: 22.8 g
- Chickpeas: 20.5 g
- Flour: 10 g
- Raw starch: 10 g
- Bread: 8 g
- Cooked starch: 2 g
- Fresh vegetables: 1 g
- Fresh fruit: 0.5 g
Eating meals that include sufficient amounts of protein is also beneficial because the digestion process for this nutrient is slow. Incorporating high-protein foods into your meals helps you achieve a longer-lasting feeling of satiety.
How much protein do you need?
It is important to consume good quality protein daily and in adequate quantities relative to your daily needs. For a non-athletic adult, ANSES recommends that protein intake cover 10 to 20% of total daily energy intake with a minimum of 0.83 g of protein/kg of body weight/day. However, these are reference values, corresponding to a minimum daily requirement for a healthy adult and not an ideal to be achieved. For athletes, everything depends on the type of physical activity practiced and your goals. However, it is recommended to consume between 1.2 and 2 g of protein per kg of body weight per day. Such an intake allows for optimal reconstruction of muscle fibers damaged during exercise.
For example, a 70 kg man will need to consume between 84 (70×1.2) and 140 (70×2) grams of protein per day.
How to distribute protein consumption in your diet?
It is recommended to spread your total protein intake over all your meals to promote better absorption and digestion. For certain at-risk populations, such as the elderly, it may be recommended to consume the majority of your daily protein in one serving in the morning.
What is whey protein?
Whey protein, also known as whey protein or lactoserum, is a protein extracted from cow's milk. It is rich in essential amino acids and ideal for muscle growth. It is the most widely used dietary supplement among athletes for muscle repair and building thanks to its rapid absorption. Whey protein should therefore be taken around workouts. Its low lactose content makes whey protein easily digestible and suitable for people with lactose intolerance.
Should you follow a high-protein diet?
It can be useful to resort to a high-protein diet if you want to increase your muscle mass, coupled with intensive sports training. Paradoxically, it is also common to resort to a high-protein diet when you want to lose weight. Indeed, protein, along with fiber, provides a feeling of rapid and lasting satiety. However, be careful, the best way to lose weight healthily and sustainably is to have a varied and balanced diet. Furthermore, know that it is useless to consume more protein than your body needs because any excess will be eliminated and not used to repair your muscles. Protein is only useful for bodybuilding, true or false? False. Protein is an essential nutrient regardless of your goal. Athlete or not, you must consume protein to avoid the loss of your muscle mass but also potential health problems. However, taking protein supplements (whey protein, protein bars, etc.) is actually more useful for athletes who want to increase their muscle mass and have access to faster-absorbing proteins.
What is casein?
Casein is a milk protein like whey. Milk contains 80% casein and 20% whey. It differs from whey protein in that it is digested more slowly by your body. Therefore, the timing of this protein consumption is different to maximize your muscle gains. Casein helps fight muscle breakdown and should ideally be taken with snacks or before bed. Conversely, whey is conducive to muscle building and should be taken around workouts.
In summary.
Proteins play essential roles in the proper functioning of our bodies. There are two types of protein: plant protein and animal protein. ANSES recommends consuming 10 to 20% of total energy intake from protein for a reference adult and 1.2 to 2 g/kg of body weight/day for athletes. It is recommended to spread protein consumption throughout the day.
