Are high protein diets healthy?
Over the years, various so-called "high protein" diets have come in and out of fashion, either with the goals of weight loss or building muscle mass. Many people believe that a high protein diet is the most healthy choice, but the fact is that consuming too much protein isn't healthy at all.
Most people in the U.S. have diets that are adequate in protein without the need for supplementation or consuming excess protein intentionally. Only elderly women, strict vegetarians with an unbalanced diet, and people with certain conditions, including eating disorders, are at risk for too little protein consumption.
What foods contain protein?
Protein, while typically associated with meat consumption, can be found in a variety of other foods, like nuts and seeds, milk products, tofu, eggs, dry beans, and peas. Even some grains, vegetables, and fruits contain a small amount of protein.
Animal-based foods are sometimes referred to as complete proteins; this means that they contain all the essential amino acids your body needs to function properly. These proteins are also known as high-quality proteins. Incomplete proteins contain some, but not all, of the essential amino acids. Incomplete, or complementary, proteins are found in grains and plant-based protein sources. Formerly, it was believed that one needed to eat incomplete proteins together with other incomplete proteins at the same meal to balance out the lacking amino acids; now, research has shown that the incomplete proteins can be eaten any time during the same day for the body to combine the complementary proteins.
The recommended amount of protein consumption is about 10%-35% of your daily calories. Adult women need, on average, 46 grams of protein a day, while adult men need about 56 grams. A 3-ounce portion of meat has about 21 grams of protein, and 8 ounces of yogurt has about 11 grams. One cup of dry beans contains about 16 grams of protein.
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What happens when I eat too much protein?
Consuming excess protein in the diet (over 35% of total calories), especially with carbohydrate restriction, can lead to the buildup of toxic ketones, substances made when the body uses its own fat cells for fuel in the absence of sufficient carbohydrates. Ketones can harm the kidneys as they try to excrete these substances. This is accompanied by a corresponding loss of water through the kidneys, leading to dehydration. Symptoms of consuming a ketogenic diet can include
There is excess stress on the heart, and muscle mass and bone calcium both decline. The American Heart Association does not recommend high-protein, low-carbohydrate diets because they often contain high-fat foods and can lead to deficiencies in some nutrients like fiber and certain vitamins. A healthy and balanced diet is by far the best choice for those who want to lose weight or improve athletic performance.
Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine
United States. Centers for Disease Control and Prevention. "Nutrition for Everyone: Protein." Oct. 4, 2012. <http://www.cdc.gov/nutrition/everyone/basics/protein.html>.