Protein and amino acids are considered the building blocks of our bodies, aiding in the growth of everything from muscles to tendons and organs to hormones. Protein is made from more than 20 amino acids, nine of which are considered essential and can only come from food. We need protein to keep repairing our bodies as we age. Since our bodies don’t store amino acids and must make them, it’s vital to understand that not all amino acids are the same.
Signs You’re Not Consuming Enough
In the United States, we may not be as familiar with the signs of protein deficiency and malnourishment as many are in the developing world, where millions lack access to protein-rich foods.
Serious signs of protein deficiency include:
Weakness of the heart/respiratory system
Overall weakness and fatigue
Problems with hair, skin and nails
Slower wound healing
Decreased muscle mass
Increased bone fractures
Complete proteins are foods that contain the nine essential amino acids everyone needs to thrive. Animal-based proteins, such as meat, fish, poultry, eggs and dairy are the best and most accessible sources, along with a few plant-based proteins, such as quinoa, buckwheat and soybeans.
But these plant sources often do not contain as much protein per serving as animal products, which can make meatless diets a challenge. Vegetarians and vegans are at higher risk of being protein deficient and should especially be aware of these differences.
How Much Protein? A Few Factors
The average adult male needs about 60-90 grams of protein per day while adult females need 45-75 grams, according to the National Institutes of Health. Individuals who are especially active every day, such as nurses, will likely have higher protein requirements to meet their nutritional needs. Older adults also need more protein to prevent health issues like sarcopenia (muscle loss due to aging). Athletes or people recovering from injury also may need more protein than average. Your individual dietary needs will depend on your own health history.
A comprehensive resource guide on proteins, including nutrition by age, by health condition plus tips for those on food assistance programs and more, is provided by the U.S. Department of Agriculture.
Too Much Protein and Other Myths
Some people believe that high-protein diets can cause kidney problems or make you fat, but neither of these are true. Simply put, the body does not convert excess protein to fat. Research shows that protein-rich diets lead to significant benefits, such as lowering blood pressure and reducing diabetes. And because protein takes longer to digest, it has a satiating effect, helping you feel fuller for longer.
When you boost your protein intake, you may notice an increase in how many calories your body burns each day. Known as the thermic effect of food, these calories are burned as you digest your food and make up to 10 percent of your daily calorie expenditure. Protein uses more energy to digest than anything else, and so your body burns more calories when you eat more protein.
These factors often allow people to lose weight or prevent weight gain simply by adding more protein to their diets. If you’re trying to lose weight, not being hungry all the time can be a big help!
Protein is also a stimulus for muscle growth. So if you boost your protein intake while consistently lifting weights and working out, you can expect to see an increase in your amount of lean muscle mass as well. Many coaches and trainers suggest much higher daily protein amounts for athletes and/or bodybuilders, or about 1-1.5 grams of protein per pound of bodyweight each day.
Finally, no solid evidence exists that plant-based diets improve performance more than animal-based diets. In fact, some evidence suggests the opposite — that because of the relatively higher proportion of certain muscle-building amino acids like leucine, animal-based diets can make building muscle easier than similar plant-based diets, which lack leucine. The same goes for certain B-vitamins, which are plentiful in animal proteins but are not found in equivalent amounts in plants.