Are you eating enough protein, or too much?

High-protein diets to lose weight or boost muscle have been around for decades – witness the popularity of Atkins, paleo and carnivore diets, as well as protein powders and shakes.

Adherents swear by them, but are these diets good for you? Who might benefit from eating more protein and who should be more mindful of their intake?

Cape Cod Hospital registered dietitian Rachel Songer, LDN, does not recommend following a high protein diet to lose weight. Fad diets usually become unsustainable for most people, she said.

“Stick with something feasible to stay with down the road,” she said. “Your average person – there’s no health benefit to a high-protein diet.”

Eating too much protein to lose weight can backfire, as your body will convert the excess protein into fat, she said.

“Your body knows what it needs. It’s not a ‘more is better’ kind of thing,” she said.

In addition, regularly consuming a lot of protein can tax your kidneys – your body’s filtration system.

“Your kidneys are working extra hard to excrete all this urea, nitrogen (from the protein),” she said. “You need to make sure you’re staying hydrated when you’re eating high protein. Helps to filter out all that extra nitrogen.”

The Case for More Protein

Some researchers say high protein diets can be a healthy way to lose weight. A September 2020 article in the Journal of Obesity and Metabolic Syndrome says 6-12-month clinical trials demonstrated high-protein diets can help people lose weight and keep weight off without reducing kidney function in healthy adults. Longer studies should be performed to confirm these results, the researchers noted.

Other researchers say some groups of Americans don’t get enough protein – notably older adults.

Humans require a sufficient amount of protein to maintain good health. Digestion breaks down proteins into amino acids that fulfill many roles. According to the U.S. Department of Agriculture, they help:

• Build every type of tissue – including muscle, blood, bones and skin, as well as hair, connective tissue and nails.
• Create enzymes used to perform cellular processes.
• Make hormones to regulate growth and metabolism.
• Provide energy to fuel the body. Protein, along with carbohydrates and fat, form the three main sources of dietary calories.

Some people do need more protein than others. Pregnant and lactating women, infants, children and teenagers require more protein to aid in proper growth and development, according to the National Library of Medicine.

People recovering from surgery need extra protein to promote wound healing, according to Songer.

There is research that indicates older adults should consume more protein to help offset age-related muscle loss, called sarcopenia, according to the National Resource Center on Nutrition and Aging.

“A lot of elderly people do benefit from it,” Songer said.

How Much Protein?

The U.S. RDA (recommended dietary allowance) for daily protein consumption for adults is 0.8 grams per kilogram of body weight. For someone weighing 150 lbs., or 68 kg., this would amount to 54.4 grams of protein per day. A 130-lb. adult would need 47 grams, and a 180-lb. adult would need 65 grams.

However, some health organizations argue this formula should be based on ideal weight, not actual weight, in light of the obesity epidemic, notes a January 2021 paper in Advances in Nutrition. The researchers also wrote that the RDA for adults remains the same despite differences in age, sex and body type, and ignores special needs of athletes and other physically active adults, the elderly and those with kidney disease.

Eating enough protein to satisfy the RDA isn’t difficult for most adults. Here’s some common foods and their protein content, from the U.S. Department of Agriculture:

• Ground beef, 90 percent lean, 3 oz. 22.19 grams
• Fried chicken, 3 oz. 19.41 grams
• Firm tofu, 4 oz. 21.76 grams
• Haddock, raw, 3 oz. 13.87 grams
• Plain low-fat yogurt, 6 oz. 8.93 grams
• Canned white tuna in oil, 3 oz. 22.5 grams
• Black beans, uncooked, 8 oz. 41.9 grams
• Cured ham, cooked, 3 oz. 12.82 grams
• Pasta, dry, enriched, 8 oz. 11.87 grams
• Peanuts, dry-roasted and unsalted, 8 oz. 35.5 grams
• Cheddar cheese, 8 oz. 30.19 grams
• Top sirloin beef steak, trimmed and broiled, 3 oz. 22.78 grams
• Whole milk, 8 oz. 8 grams
• Eggs, uncooked, 1 large. 6.28 grams
• Sunflower seeds, shelled and oil-roasted, no salt, 8 oz. 27.08 grams

These foods differ not only in the amount of protein they contain, but their fat, salt and sugar content as well, so you’re adding those, too, when you eat them. Getting your protein mainly from red meat has been associated with developing cardiovascular disease, type 2 diabetes and some cancers, perhaps, in part, from the animal fat it contains. A study, published April 2019 in the American Heart Association Journal Circulation, comparing diets high in red meat to those high in plant sources (legumes, nuts and soy) showed consumption of plant-based protein resulted in healthier levels of total cholesterol and low-density cholesterol. Plant foods also may decrease the risk of kidney damage in patients who require more protein, according to a December 2020 article in Nutrients.

“Typically, if you’re a meat eater, you get plenty” of protein, Songer said. “Vegans and vegetarians need to be a little more mindful,” though plant foods contain all the essential amino acids.

She suggested not trying to get the bulk of daily protein in a single meal.

“Your body can only handle so much at once,” Songer said. “Space it out.”

She recommended people discuss their eating habits with their doctor and said a dietitian could calculate their specific protein needs.

“It’s always a balancing act,” she said.

Two Special Categories

Songer advocates getting protein from less processed foods, eating less red meat and incorporating more fruits and vegetables into your diet for their natural nutrients and fiber, rather than relying on protein powders and drinks, which can contain added sugar. However, she said, these supplements can be useful for elderly people who may not cook often, don’t have much of an appetite and may rely on snacks or one meal a day for their nutrition. According to the National Resource Center on Nutrition and Aging, older adults may need 1-1.2 grams of protein per kg of body weight. That’s 20-50 percent more than the standard RDA for adults.

“A lot of elderly people are at risk,” she said. “Getting adequate protein is important.”

At the other extreme are people with chronic kidney disease. Consuming too much red meat, shellfish and organ meats can increase the risk of kidney stones made of uric acid, according to the National Kidney Foundation. These same foods are high in purines, and eating too much of them and drinking alcohol can lead to gout, a painful type of arthritis when urate crystals form in joints, often in the big toe or leg, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

Therefore, people with kidney disease need to restrict their protein intake, especially those who haven’t progressed to dialysis to filter out wastes from their blood, Songer said. Once on dialysis, their protein levels can be increased somewhat.