Why is everyone so obsessed with protein?

Key takeaways

A reasonable variety of ordinary foods generally supplies enough protein; Gardner says Americans consume about 50% more than the RDA already.
Protein cannot be stored as a reserve, so excess is converted into carbohydrate or fat and may displace fiber-rich plant foods.
Weight-loss studies cited by Gardner found little meaningful advantage for high protein, while good food quality mattered more than choosing low-fat or low-carb.
Only 5% of Americans eat enough fiber, which supports gut bacteria and the protective intestinal lining.
Until microbiome-based dietary recommendations become more reliable, the guests’ practical advice is to eat more legumes, vegetables, fruits, and other whole foods.

Summary

The protein recommendation is already padded with safety margins

Host Flora Lichtman asks Stanford nutrition researcher Christopher Gardner where the familiar 50-to-70-gram protein recommendation came from. Gardner traces it to nitrogen-balance studies from roughly 70 years ago, in which researchers measured nitrogen entering and leaving the body after changing subjects’ protein intake. The estimated requirement was 0.66 grams per kilogram, or about 0.3 grams per pound, then raised to 0.36 grams per pound to protect people above average. Gardner says Americans already eat about 50% more than that RDA, and protein is not a major nutrient concern; fiber is more often lacking.

Protein became important through meat, labor, and bodybuilding

Food historian Hannah Cutting-Jones traces protein’s status to 1840s German chemists, who separated food into protein, carbohydrates, and fat but treated protein—closely associated with meat—as the most important. During industrialization, researchers recommended high protein for manual laborers, while 1950s bodybuilders and weightlifters adopted supplements. She cites coach Bob Hoffman’s homemade soy-protein chocolate sludge for the U.S. weightlifting team as an early “chicken shake.” Protein remained niche until later dietary politics made it central to mainstream food marketing.

Diet research did not show that high protein wins

Gardner says the 1990s food pyramid followed battles over saturated fat and red meat, with the meat industry resisting recommendations that might reduce meat consumption. After 2003 studies connected higher-protein diets with weight loss and maintenance, protein products gained a new audience. But Gardner’s own trials found good-quality low-fat and low-carb diets essentially tied, with food quality more important than the ratio. In the two-year, 800-person Pounds Lost study, participants assigned to 15% or 25% protein drifted toward roughly 20%, so the trial could not really test high versus low protein.

Excess protein cannot be stored—and may crowd out better food

Asked whether protein can be saved for a rainy day, Gardner says the body stores unlimited fat and limited carbohydrate but has no dedicated protein reserve. After protein is used for cell repair, enzymes, hormones, hair, and fingernails, the remainder is converted to carbohydrate and then fat if carbohydrate stores are full. Protein-maxing can also displace fiber, vegetables, legumes, and beans. Cutting-Jones says protein products commonly use whey and soy; whey was once cheese-making waste before becoming the basis of a multibillion-dollar supplement business.

Fiber is old, useful, and less glamorous than protein

Cutting-Jones says fiber-maxing is not new: John Harvey Kellogg and his brother Will promoted bran flakes and corn flakes in the 1870s to replace greasy, meaty diets with plant foods. Only 5% of Americans eat enough fiber, but fiber lacks protein’s links to appearance, athletic performance, weight loss, and aging, instead being associated with prunes and bowel movements. Gardner explains that fiber is a carbohydrate-like molecule humans cannot digest, so it reaches the colon, where gut bacteria ferment it into compounds that can lower inflammation and support the gut lining.

The guests recommend whole-food “maxing” and join the leguminati

Gardner says every food, including plants, contains all 20 amino acids, and the proportions in chickpeas, lentils, and whole grains are more similar to meat than people assume; plants simply contain less total protein. Fibers come in dozens of forms, and future personalized medicine might match a person’s missing microbes with foods such as oats or lentils, but the science is not there yet. Until then, he and Cutting-Jones recommend more legumes, vegetables, and fruit. Flora endorses “whole food max” and jokes that listeners should join the “leguminati.” She closes by asking for foraging stories at 877-472-4374.

Show notes

It’s impossible to ignore the latest nutrition trend: protein-maxxing. Stroll through the grocery store and you’ll find protein chips, protein-packed ice cream, and even sparkling protein water. Not to mention the FDA’s new upturned food pyramid, which puts steak and a roast chicken at the top.

Where did this protein craze come from, and how much protein do we actually need? And what about protein-maxxing’s less popular cousin, fiber-maxxing? Flora talks through the history and the science of protein and fiber with food historian Hannah Cutting-Jones and nutrition researcher Christopher Gardner.

Guests:

Dr. Hannah Cutting-Jones is a food historian and assistant professor at the University of Oregon.

Dr. Christopher Gardner is a nutrition researcher, a professor at Stanford Medicine’s Prevention Research Center, and the author of “Food Sense: What to Eat and Why.”

Transcripts for each episode are available within 1-3 days at sciencefriday.com.

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