Protein is an extremely important nutrient that we must get through our food because we can’t synthesize it on our own. Children need protein for growth, and adults need protein for the repair of tissues and for daily detoxification. However, too much of this nutrient can be detrimental to your health. In the short term, taking in more protein than you need can lead to low energy and reduced athletic performance because your body has to work extra hard to convert protein to glucose to use as fuel. Over the long term, excess protein can increase your likelihood of developing diabetes, tumors, heart disease, infertility, and osteoporosis. It may also accelerate the aging process and shorten your healthspan (the age at which you live free of chronic disease).
So how much protein do you need for growth and tissue repair without getting too much of a good thing? Many scientists agree that 0.6 grams of protein per kilogram of body weight is the magic number for staying in positive protein balance, and this number has been elevated by two standard deviations to account for outliers who may have slightly higher protein requirements due to strenuous exercise or recovery from illness. Therefore, the optimal amount of protein is 0.8 grams per kilogram of body weight for ages 19 – 65. This amounts to about 55 grams of protein for a 150 pound adult. Because adults over age 65 do not produce as much growth hormone, and because they do not utilize amino acids as efficiently, they have increased protein requirements. The “magic number” for adults over age 65 may be 1.3 grams per kilogram of body weight. This amounts of 88 grams of protein daily.
These are optimal requirements — not minimal requirements! If you are under age 65, you are probably eating too much protein. The good news is that proteins coming from whole plant-based foods — such as broccoli, beans, and potatoes — has not been shown to have the detrimental effects that excessive animal-based proteins produce. Therefore, if your optimal protein intake is only 55 grams, but you’re getting 90 grams of protein daily, you’re doing just fine if most of that protein is coming from whole plant foods such as lentils and kale. Instead of focusing on “not eating too much protein,” your best plan of action is to get the majority of your calories (and protein) from whole plant-based foods.
I’ve written more about why this dietary shift is so critically important for multiple facets of your health (and what exactly you should be eating) in my latest book, Plant-Powered Paleo: The New High Carb Lifestyle for Omnivores. It’s on sale now right here. Recipes and a meal plan are included at the end of the book, which will give you a jumpstart into a healthier, more delicious way of nourishing your body with real food.