Fiber is essential for keeping your intestines and gut microbiome healthy, he said. It helps keep your bowel movements regular and serves as food for your gut microbes. Diets higher in fiber can also reduce the likelihood of developing certain gut disorders, like irritable bowel syndrome, he said.
Mr. O’Meara recommended aiming for equal portions of vegetables, protein and whole grains at most meals. Or, if you’re trying to limit calories to lose weight, he said, make half of the plate vegetables and a quarter each protein and whole grains.
Weight Gain
A popular claim on social media is that you must follow a high-protein diet if you want to lose weight or gain muscle. But if you’re not doing enough strength training or other exercise to match your increased protein consumption, Dr. Mozaffarian said, any excess calories, including those from protein, will be turned into fat.
Mr. O’Meara also noted that favoring protein-rich foods over vegetables could lead to weight gain. A half-cup of cooked vegetables, for instance, has an average of about 25 calories, whereas a half-cup of cooked chicken has about 140 calories, he said. If you triple a serving of chicken to eat more protein, you consume five to six times as many calories as you will if you triple a serving of vegetables, Mr. O’Meara said.
Kidney Issues
If your kidneys are healthy, you probably don’t need to worry much about excess protein consumption, Dr. Hensrud said. However, for the more than 1 in 7 Americans with chronic kidney disease — especially those who may be close to needing dialysis — metabolizing large amounts of protein can stress the kidneys, Dr. Hensrud said, further reducing kidney function.
Kidney stones are also a potential side effect of consuming too much animal protein, Dr. Hensrud said. If you drink enough water, however, your risk is far lower.