The Importance of Protein
The Importance of Protein
Why is protein important for our bodies?
Amino acids are the building blocks for protein. There are 22 amino acids that the body uses to make the thousands of body proteins needed to sustain life. Nine of the 22 amino acids are called essential amino acids, which means our bodies cannot make them; therefore, we need to get them from the food we eat.
Protein is used for:
- Growth and maintenance of tissues within the body. Your body is constantly breaking down protein and then making more protein to build and repair tissues. Usually your body will break down the same amount of protein that it rebuilds. However, there are times that your body breaks down more protein than it can create (such as when you are ill or during pregnancy) and your body will need more dietary protein. Other people who need more protein are people recovering from a surgery or an injury, older people and athletes.
- Making enzymes. Enzymes are proteins that help with the thousands of biochemical reactions that take place within your body. Body functions that use enzymes include: digestion, energy production, blood clotting and muscle contraction.
- Communication between your cells, tissues and organs. Hormones are proteins that help regulate things like fluid balance (antidiuretic hormone), growth (human growth hormone), and blood glucose levels (insulin and glucagon). There are also proteins in your blood (albumin and globulin) that help maintain fluid balance by attracting and retaining water and prevent fluid from going into the spaces between your cells which can lead to swelling or edema.
- Structure, strength and elasticity in certain cells and tissues. Some of the fibrous proteins are keratin (found in skin, hair and nails), collagen (found in bones, tendons, ligaments and skin) and elastin (found in uterus, lungs and arteries).
- Immune health. Proteins form antibodies to help protect your body from disease-causing bacteria and viruses.
- Transporting and storing nutrients. Transport proteins will carry substances like vitamins and minerals, blood glucose, cholesterol and oxygen throughout your body and into and out of cells. For example, hemoglobin is a protein inside of red blood cells that carries oxygen from your lungs to body tissues. Ferritin is a storage protein that stores iron, mostly in the liver.
- Energy. Proteins can supply your body with energy (4 calories per gram of protein). Carbohydrates also supply your body with 4 calories per gram while fats provide 9 calories per gram. Your body has a storage system for carbohydrates (glycogen) and fats and these reserves can be used as fuel. In addition, these macronutrients are metabolized more efficiently compared to protein. Since protein is used throughout the body for many other functions, your body would prefer to not use protein for energy.
How much protein do we need?
We cannot store extra protein as muscle or amino acids so we need to eat enough protein each day. It is better to try and evenly distribute the protein we eat throughout the day. This will allow more amino acids to be available for muscle repair, muscle protein synthesis, and the many other functions of protein mentioned above. The body needs only about 20-25 grams of protein at a time to stimulate muscle growth. Adding protein to meals and snacks helps to promote feelings of fullness and decreases blood sugar levels compared to when only eating carbohydrates. Including protein (as well as fiber and healthy fats) when eating slows down digestion so that blood sugar doesn’t go up as high or as fast after eating.
The Recommended Dietary Allowance (RDA) for protein is 0.36 grams of protein for every pound of body weight; however, this is now considered a minimum amount. For adults who exercise regularly, the recommended amount is 0.5-0.7 grams of protein per pound of body weight. For adults trying to build muscle mass, stay in the upper end of the range (0.7 grams). An adult with extra body fat should not use their actual weight when figuring out how much protein they need but rather use a weight that is closer to their Ideal Body Weight (IBW). IBW for men is 106 pounds for the first 5 feet of height + 6 pounds for each additional inch. For women IBW is 100 pounds for the first 5 feet of height + 5 pounds for each additional inch.
Examples (Adults who exercise regularly/are trying to build muscle mass)
To determine the recommended amount of protein for a man who is 6 feet tall and weighs 250 pounds:
IBW is 178 pounds. This amount could be rounded to 200 pounds (a weight that is closer to this person’s IBW than his actual weight). So the recommended protein range would be (0.5 x 200) – (0.7 x 200) or 100-140 grams of protein per day. Ideally this protein would be spread out throughout the day. If this man were eating 3 meals and 3 snacks each day, he could have 25-30 grams of protein for each of the 3 meals and about 10-15 grams of protein with each snack.
To determine the recommended amount of protein for a woman who is 5 feet 4 inches tall and weighs 170 pounds:
IBW is 120 pounds. This amount could be rounded to 140 pounds (a weight that is closer to this person’s IBW than her actual weight). So the recommended protein range would be (0.5 x 140) – (0.7 x 140) or 70-98 grams of protein per day. If this woman were eating 3 meals and 3 snacks each day, she could have 20-25 grams of protein for each of the 3 meals and about 5-10 grams of protein with each snack.
What about protein supplements?
The amounts of protein in the above examples can be easily consumed when a person eats protein rich foods. Since foods contains other essential nutrients besides protein, it makes sense to try and meet your protein needs through food rather than relying on protein supplements. In addition, protein supplements tend to be highly processed. Supplements are not regulated as rigorously as foods and drugs so you may not be receiving the amount of protein that is listed on the Nutrition Facts Label. In addition, protein supplements sometimes contain artificial sweeteners or high fructose corn syrups to give the product has a sweet taste. If you do decide to use a protein supplement choose one with no added sugars or one that is naturally sweetened.
What and when should we eat before and after exercising?
It is important to fuel your body before and after exercising. For workouts that are 60-90 minutes in length having a snack about an hour before exercising that is mostly carbohydrates which empty quickly from the stomach and provide energy for the muscles is a good option. If the exercise will be longer than that adding some protein to the snack will provide more sustained energy. Try and eat within a few hours after exercising or sooner if you are hungry. It is important to eat something that contains both protein and carbohydrate since the muscles can use amino acids from the blood to build muscle, and the muscles can absorb carbohydrate from the blood to replenish depleted glycogen stores.
What foods are high in protein and low in fat?
Animal Sources
| Food | Amount of Protein (grams) | Amount of Fat (grams) |
| Egg White (from 1 large egg) | 3.5 | 0.1 |
| Large Egg | 6 | 5 |
| Nonfat Greek Yogurt, plain (5.3 oz) | 14-15 | 0 |
| Nonfat Milk (8 oz) | 8.7 | 0.6 |
| Light String Cheese (1 oz) | 6 | 2.5 |
| Shrimp (3 oz) | 19 | 1.4 |
| Cod (3 oz) | 17 | 0.2 |
| Tilapia (3 oz) | 22 | 2.4 |
| Tuna, canned in water (3 oz) | 16 | 0.5 |
| Chicken Breast (3 oz**) | 27 | 2.8 |
| 93% Lean Ground Turkey (3 oz) | 16 | 6.1 |
| Boneless Pork Loin (3 oz) | 26 | 5 |
**3 ounces of meat or fish is about the size of a deck of cards.
Plant Sources
| Food | Amount of Protein (grams) | Amount of Fat (grams) |
| Quinoa (3/4 cup cooked) | 6 | 2.6 |
| Oatmeal (1 cup cooked) | 5 | 2.5 |
| Kidney Beans (1/2 cup) | 8 | 0.4 |
| Black Beans (1/2 cup) | 7 | 0.4 |
| Low-Fat or Oil Free Hummus (1/4 cup)** | 4 | 0 — 4 |
| Lentils (1/2 cup cooked) | 12 | 0.5 |
| Tofu, extra firm (3 oz) | 8 | 4.5 |
| Edamame (1/2 cup, shelled pods) | 9.2 | 4 |
| Green Peas (1/2 cup) | 4.1 | 0.2 |
| Peanut Butter Powder (2 Tbsp, 16 g) | 8 | 2 |
**Look for hummus that has 2 grams of fat or less per 2 Tbsp serving. Some good options: Lantana Brand Hummus (Black Bean, Pumpkin Spice, or Beet Hummus), Hope Brand Black Garlic Hummus, Wild Garden Brand Traditional Hummus; Roots Brand Oil-Free Original Hummus; Cedar’s Brand Fat and Oil Free Hummus; or make your own hummus using an Oil-Free Hummus recipe (use this Low Fat Hummus recipe on the Health Plus Website or look online).
What happens if we don’t eat enough protein?
As discussed earlier, protein is required for many of the body’s functions so your body needs plenty of protein from dietary sources to stay healthy and work the way it should. If you don’t consume enough protein, your body will need to break down the protein stored in muscles so that the body has the amino acids it needs to make hormones, enzymes, antibodies, transport and storage proteins, etc. This would cause you to lose muscle mass which will decrease your strength and slow down your metabolism.
Information compiled from:
Healthline
Nancy Clark’s Sports Nutrition Guidebook, 6th Edition (2020)