You need protein for various functions. Protein provides structure for cells and tissues and is a component of enzymes that run various biochemical reactions. Proteins are major components of bodily fluids that help maintain fluid balance within and between cells. You also need the amino acids that makeup protein to build muscle tissue. These are all reasons why you shouldn’t fall short of this essential macronutrient that you get from your diet.
Yet you need your macronutrients in a healthy balance, enough protein but not too much. As with most things in life, more isn’t always better. Some athletes and bodybuilders consume several protein drinks each day in addition to their meals. It’s true that athletes need more protein because they break down muscle tissue when they train, and that tissue needs repair. Plus, high-protein diets for weight loss are popular because they increase satiety and reduce the desire to eat. But is there a point where consuming more protein offers no further gains or even becomes harmful?
How Much Protein Do You Need?
Do you really need to sip that protein drink after a workout? How much protein you need is partly related to how physically active you are and how intensely and often you exercise. Although scientists don’t know the exact amount of protein people need for optimal health, they’ve established some guidelines.
The guidelines say a sedentary person needs 0.8 grams of protein per kilogram of body weight. That’s around 50 grams of protein for the average person who weighs 140 pounds. You can easily get that amount of protein through diet if you don’t eat a restrictive diet or consume a vegan diet. Even on a vegan diet, it’s not hard to eat enough high-protein plant foods to meet that requirement.
If you’re physically active, you need more protein since you’re sustaining more muscle damage when you train. Experts believe that people who exercise need between 1.6 and 2.0 grams of protein per kilogram of body weight to account for the extra demands on their muscles. Most people who exercise with the exception of athletes who train strenuously daily will do fine with around 1.6 grams of protein per kilogram of body weight, and there’s little benefit to getting more.
How Much Protein is Too Much?
Protein is a controversial topic. Some experts believe the average American diet already contains too much protein. Is there an upper limit of protein you shouldn’t exceed? At one time, there was concern that consuming a high-protein diet places strain on the kidneys and could cause kidney damage if extreme and prolonged. Fortunately, there’s no evidence that high protein is harmful to healthy kidneys, but if you have reduced kidney function, experts don’t recommend consuming a high protein diet. If your kidney function is significantly reduced, a low-protein diet to help reduce further strain on the kidneys is recommended. Metabolizing protein is more complex than breaking down carbohydrates and fats and your kidneys must work a bit harder to clear the metabolites.
What is a high-protein diet? It’s consuming more than 1.2 grams of protein per kilogram of body weight. Patients with mild kidney failure are advised to consume no more than 0.8 grams of protein per kilogram of body weight per day. Studies show a lower protein diet can slow how quickly chronic kidney disease progresses. So, you wouldn’t want to go on an Atkin’s or a very-low carbohydrate diet if you have reduced kidney function.
Some studies also show that eating an abundance of protein places an added metabolic demand on the body. It takes more energy for your body to break down protein than carbohydrates or fat. In some respects, this is beneficial since you burn more calories breaking down protein and that makes it easier to lose weight. But there’s also evidence that a high-protein diet increases the risk of cardiovascular disease and some forms of cancer. The greatest risk comes from animal protein, including red and processed meat.
Type of Protein
The source of your protein matters too. Plant-based protein sources don’t seem to carry the same health risks as animal-based protein. According to the National Institutes of Diabetes, Digestive, and Kidney Diseases, consuming vast quantities of animal protein increases the risk of kidney stones. Making more plant-based protein choices doesn’t seem to increase the risk in the same way as animal protein.
Diversify your protein sources and make sure you’re getting some of your protein from plant-based sources. Soy, beans, lentils, dried peas, and some whole grains are healthy options that also contain fiber. Even vegetables contain protein. However, except for soy, most plant-based protein sources lack or are low in one or more essential amino acids. You can make up for this shortfall by eating a variety of plant-based protein sources.
The Bottom Line
Help yourself to more protein if you’re physically active, but don’t go overboard. Rather, consume a balanced diet that includes some plant-based protein, combined with an abundance of fruits and vegetables. Unless you’re in a hurry and can’t eat a meal, you probably don’t need that protein shake.
The best way to consume protein is by eating it as part of a balanced diet, along with other nutrients like carbohydrates, fats and vitamins and minerals. Drinking protein shakes on occasion isn’t harmful but consuming more than 2.0 grams of protein per kilogram of body weight is overkill for most people, even athletes. Whether it carries longer-term risks, beyond a higher risk of kidney stones, is still unclear.
References:
- “Dietary Protein Intake and Chronic Kidney Disease.” ncbi.nlm.nih.gov/pmc/articles/PMC5962279/.
- Narasaki Y, Okuda Y, Moore LW, You AS, Tantisattamo E, Inrig JK, Miyagi T, Nakata T, Kovesdy CP, Nguyen DV, Kalantar-Zadeh K, Rhee CM. Dietary protein intake, kidney function, and survival in a nationally representative cohort. Am J Clin Nutr. 2021 Jul 1;114(1):303-313. doi: 10.1093/ajcn/nqab011. PMID: 33742197; PMCID: PMC8246621.
- “Eating, Diet, & Nutrition for Kidney Stones | NIDDK.” niddk.nih.gov/health-information/urologic-diseases/kidney-stones/eating-diet-nutrition.
- Delimaris I. Adverse Effects Associated with Protein Intake above the Recommended Dietary Allowance for Adults. ISRN Nutr. 2013 Jul 18;2013:126929. doi: 10.5402/2013/126929. PMID: 24967251; PMCID: PMC4045293.
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