Garth Davis, a weight-loss surgeon who runs a clinic in Houston, tells a story about a patient of his, a woman who became terrified of yams. Originally from Ghana, she had grown up with them as a staple, but abandoned her traditional diet in favour of the Western way: eggs for breakfast, a salad with chicken midday, a protein shake for a snack, and a breast of grilled chicken for dinner. When Davis asked why she thought she was gaining weight, she blamed the carbs. “What carbs?” he said. “You’re not eating a single carb.” While demonizing every starch, grain and noodle available, the woman had embarked on a ceaseless pursuit of protein. Like thousands of Davis’s patients—and for a time, Davis himself —the woman was convinced that protein was the answer to her weight-loss woes.
His patients weren’t alone. When Davis started paying attention, he began to notice signs of an obsession everywhere: the profusion of protein bars at convenience stores, the fashionability of protein superfoods like quinoa and chia, the “high-protein” claims on cereal boxes, all promising to kill hunger and cut pounds. Meanwhile, Davis was also seeing athletes and seniors eating protein to gain weight. Indeed, he concluded, we are hailing protein as the all-purpose, must-have macronutrient; it helps us slim down, it helps us bulk up, and supposedly makes us all-round healthier. The phenomenon impelled him to delve into research from scientists, epidemiologists and market analysts to figure out just how much protein we’re packing into our diets and whether it’s actually making us unhealthier.
Related: The truth about food addiction
“We are proteinaholics,” Davis declares in his forthcoming book, Proteinaholics. “We’re on a protein binge.” Indeed, the World Health Organization found that Americans eat more than twice the protein suggested by the Dietary Recommended Intake, which is harmonized across North America. That means a 150-lb. person is eating more than half a dozen eggs’ worth of protein per day. The most recent statistics from Canada are a decade old, but market research shows egg consumption is at its highest since the 1980s; chicken consumption has shot up from about eight birds per capita per year in the 1970s to more than double that today; Greek yogourt sales have doubled over just the past decade; sales of peanut butter and other nut-based spreads are expected to rise 65 per cent between 2013 and 2018, and protein supplements are expected to more than quadruple in sales over that time. According to the Wall Street Journal, “hummus is conquering America.”
A study titled “Protein fever” from the market-research firm Mintel found that a quarter of North Americans are willing to pay a premium for high-protein foods. A liquor company in the States has even launched a protein-infused vodka, and you can now buy energy bars—once the domain of hikers who used them in place of meals while summiting mountains—on board Air Canada, never mind that you can hardly budge in your seat.
The truth is, just about every food, including ones we don’t remotely consider to be a protein source—like sliced bread or cauliflower—still provides some protein. A package of Mr. Noodles contains almost as much protein as a Clif Bar. Davis told Maclean’s, “We’ve begun this artificial calculus whereby we judge foods based on their protein content, when really there’s protein everywhere.”
There’s a constant push for us to get more. Last January, academics at a conference in Toronto, with sponsors including Danone, Dairy Farmers of Canada, Egg Farmers of Canada, Canada Beef and the Canadian Pork Council, called for raising the recommended protein intake by up to 75 per cent for some Canadians. Similarly, recommendations to raise protein levels from the Protein Summit and Protein 2.0 Summit in Washington, sponsored by the Beef Checkoff Program and National Dairy Council, were published in the American Journal of Clinical Nutrition and have been downloaded more than 75,000 times online.
Christopher Gardner, a nutrition scientist at Stanford University’s medical school, wrote a letter with his colleagues to the journal’s editor saying the recommendations are “insane.” “North Americans are absolutely confused about how much protein they need,” he says. “There is no doubt we’re eating too much protein,” concurs Valter Longo, the director of the Longevity Institute at the University of Southern California. “There’s a lot of interest in selling protein, but we’re already getting way too much. We’re obsessed.”
Never in history have we eaten so much protein. Although proponents of Atkins and the still popular Paleo diet suggest that their hefty protein intakes imitate the meal plans of cavemen, historians widely point out that our ancestors were better gatherers than hunters. Although the word protein comes from the Greek word proteos, meaning “of prime importance,” it was named for the importance of protein in making up the human body, not for its significance in the ancient Greek diet. Prior to the world wars, protein was largely reserved for the wealthy; the layperson’s diet in western European and North American countries were less like “meat and potatoes,” more like “leek and potatoes,” with meat and dairy enjoyed twice a week or less.
Canada’s first dietary recommendations, published in the Canadian Medical Association Journal in 1939, told us to get just 10 to 12 per cent of our calories from protein. Today, the recommendations give an upper range of 35 per cent of calories from protein—and higher for children and new mothers. Davis speculates the upward trend began with scientists in the 1950s who recognized that people with more body fat—the same ones who ate more animal protein—could better handle infectious disease, not taking into account chronic diseases that would come with the new alternative.
Indeed, where there’s a source of protein, there’s also a source of trouble, beginning with weight gain, some researchers are warning. “Let’s stop speculating,” says Davis. “Let’s really get into the science.”
What the science shows is that eating protein results in eating more calories, not less. The concept of “volumetrics” tells us that, because high-protein foods tend to be dense, they don’t take up much space in the stomach, meaning we need to eat more calories before our stomach receptors sense that we’re full. Meanwhile, lower-protein foods like fruits and vegetables take up a lot of space in the stomach, triggering the sense of fullness after fewer calories have been consumed.
A tablespoon of pure peanut butter contains more than twice the calories as a tablespoon of pure fruit jam—which is why it may be a convenient calorie source for, say, Canadian soldiers, who get packets of peanut butter in their rations; the extra calories are worrisome for people sitting in offices. Even the protein sources we don’t think are dense are still packed with calories. Two eggs have more calories than a packet of Quaker’s oatmeal. Although eating meat quickens metabolism by about one or two per cent, this has little impact compared to the effects of the fibre we would consume by replacing that meat with fruits and vegetables—especially since these foods hold much of their weight from fibre that doesn’t get converted into calories at all.
Many of the studies cited by protein advocates fall short of effective cases for eating protein. When nutritionist Leslie Beck wrote in the Globe and Mail last month that a high-protein breakfast helps teens lose weight, she was referencing a study of just 57 teens, in which the high-protein breakfast still contained grains and the low-protein breakfast was a ready-to-eat box of Chex, Cheerios, Oatmeal Squares or Total, rather than unrefined whole grains. When Kellogg’s claims that products like Special K protein bars “satisfy hunger,” says Davis, they are comparing their products to almost purely sugary alternatives. Researchers at the University of Sydney have studied satiety indexes of hundreds of foods; the most hunger-suppressing food they’ve found—above any protein bomb—is a boiled potato.
Protein supplements also don’t make us feel full in the way we think. If we drink a protein shake or smoothie without eating any carbs, we might think our bodies are full, but what’s happening is that our bodies start to burn fat instead of carbs. While this may sound ideal for weight loss, it’s in fact a process that releases chemicals called ketones and thereby causes nausea, headaches and fatigue. Although feeling ill may make us eat less in the short term, long-term studies show that low-carb, high-protein dieters gain weight back. Stanford University’s Gardner studied the effects of various diets on people over a period of two years. Although an Atkins regime led people to lose the most weight in six months, those people regained it faster than anyone on high-carb diets.
Even academics who argue for increased protein intake say supplements are merely extra calories. “They’re completely unnecessary,” says Stephanie Cavalier, an assistant professor at McGill’s medical school. She makes no exception for athletes, who eat more food in general and thereby automatically consume more protein, while their bodies also utilize it more efficiently than sedentary people.
The healthful glow of protein also overshadows what comes with many high-protein foods. In the case of a “protein bar” like Vector, the name can serve to justify eating a caloriﬁc chocolate-coated dessert, which can have twice as much sugar as it has protein. Similarly, restaurants will often ask us whether we would like a “protein” with our salad, referring to chicken or salmon. “Why don’t you ask me whether I’d like a fat with my salad?” Garth Davis wonders. All meat and ﬁsh—lean, organic or otherwise—necessarily comes with fat, as do plant-based proteins such as chick peas or lentils, albeit to a lesser extent.
Evidence from populations worldwide indicates that animal protein leads to weight gain. When the World Health Organization conducted one of the largest cohort studies in history, examining half a million people in 10 European countries over 15 years, the data indicated that those who consume eight per cent more animal protein are 23 per cent more likely to become overweight or obese. Researchers from the Imperial College London also found that people on a Mediterranean diet are less likely to be overweight or obese primarily because of the low meat content. Such a diet includes just morsels of meat and almost no eggs or ham. Maybe Sam I Am’s friend was onto something.
The problems with protein go beyond gaining pounds. Davis cites a signiﬁcant body of research that connects high-protein diets with a host of health conditions from diabetes to cancer. One culprit, according to his book, is amino acids, which make up proteins and have a stellar reputation for building muscle and bones, ligaments and hormones. But an abundance of acids cannot innocently float along in the blood stream. At best, you pee them out. At worst, he says, your body may buffer the acidity by pulling calcium from muscle and bone cells, a condition called acidosis. In place of calcium, fat gets deposited in cells, meaning sugar can’t enter the cells. From there, heightened sugar in the bloodstream increases the risk of type 2 diabetes.
“You’ve maxed out,” explains Gardner. “As soon as you’ve made your hair and fingernails for the day, you can’t safely store any more protein in your body.” Davis cites researchers from Harvard’s medical school, who studied 51,000 American men, finding that increasing meat consumption by half a serving a day raised chances of developing diabetes by 48 per cent.
Meanwhile, high-protein diets have been shown to hasten puberty, which, for girls, is strongly linked to future breast cancer. This can be explained by a growth hormone known as insulin growth factor-1 (IGF-1), which comes in soy, meat, fish and dairy, including whey and casein powder. Although it’s necessary for us to grow, it also helps grow cancer cells. It’s instructive that breast milk, which humans consume during the fastest growing period of our lives, derives just five per cent of its calories from protein. Compare that with the recommendation that children get around 10 to 35 per cent of calories from protein.
Cancer is just one way in which our craving for animal and plant-derived proteins can speed up mortality. Longo’s research, most recently a study of 6,000 Americans published in Cellular Metabolism last year, reveals that a 10 per cent increase in protein leads to a 75 per cent increased risk of mortality in people under 65 due to cancer, diabetes, heart disease and rapid aging. While the focus of this study was on IGF-1, Longo’s research has also found that hormones like lysine, found in most plant-derived proteins, are difficult for the kidneys to process, while choline, found in eggs, quickens the onset of prostate cancer.
As for heart disease, Davis notes the type of fats that travel with protein, and concludes, “saturated fat and protein work together to wreak their damage.” Longo says there’s a body of research to support these findings. “When you do what we do, spending the last 2½ decades studying the pathways of these hormones down to unicellular organisms, along with looking at epidemiology, you cannot say this is just an opinion.”
If we look away from the microscope, common sense alone should challenge our rosy perception of protein. “The real topic for conversation is what we know about people and who’s healthy and who’s not,” says Howard Jacobson (not the British novelist), who co-authored Proteinaholic with Davis. A global study called Blue Zones, which began as a National Geographic project to find the longest living populations on Earth, has famously identified the diets of places like Sardinia, Italy, and Okinawa, Japan, as the healthiest; their protein intakes, Davis points out, are “scandalously low.” The Sardinians eat meat just once or twice a week, and the Okinawans get just seven per cent of their calories from protein. Almost 70 per cent of the calories in the Okinawan diet comes from yams. “We should be eating starch,” says Davis. “We’re starchavores!”
That view is decidedly not shared by some experts, including Paul Pencharz, a researcher at the Hospital for Sick Children and the University of Toronto, and one of the three scientists who set the daily recommended intake for protein in 2012. Pencharz wants to now raise the recommendations by 40 to 45 per cent for kids, 30 per cent for adults, and 75 per cent for pregnant and lactating women, based on new research involving University of Toronto and Massachusetts Institute of Technology scientists. Their findings suggest we need more protein than previously thought to maintain a balance of nitrogen, which the body builds with the amino acids in protein. That nitrogen, in turn, builds bone, muscle and more.
Though Pencharz says the recommendations will change at the trickling pace of bureaucracy, he says they should change from the current 0.8 grams of protein per kilogram of body weight per day to one gram per kilogram for adults and 1.3 grams per kilogram for kids. If there’s an upper limit to how much protein we should get, he says it would be the equivalent of a 150-lb. person eating 13 eggs per day. “Everyone has their opinions on food,” he says. “I have to deal with the truth.”
Other protein promoters bring up the beneﬁts to seniors and athletes. McGill’s Stephanie Cavalier says the elderly could be protein deficient because they often have smaller appetites, tighter budgets and difficulties chewing, but she says more protein would help them mitigate muscle loss. “There are ladies who will just eat crackers, soup and a cup of tea in the course of a day,” she says. “Right there is a risk of not getting enough protein.” Although she rolls her eyes at protein supplements for the general population, she says some seniors should simply add powdered milk—no need for the luxury protein supplement brands—to their coffee or mashed potatoes.
Likewise, Stuart Phillips, a kinesiology professor at McMaster University, says recommendations should be raised by 50 to 100 per cent for adults and by 200 per cent for training athletes. “It would be a) safe, and b) associated with some benefits,” he says.
Garth Davis maintains that the research doesn’t support raising protein recommendations, even for special groups. When it comes to the elderly, he says nobody has shown there is any protein deficiency. “In a rational world, medical researchers spend their time looking for solutions to actual human problems,” he says. Moreover, Davis argues that protein may actually be the cause of muscle loss in seniors, not the solution, because the body has had a lifetime of pulling calcium from muscles and bones to buffer the acidity.
The second, equally contentious, course of the debate is which type of protein is best. “Animal protein is superior,” says Cavalier. “We have to think of the environment, but still, animal protein is the best type of protein.” Pencharz explains from his research that plant-derived proteins, such as soy, corn and rice, contain “limiting” amino acids, including the lysine found in corn and methionine found in legumes, which prevent the body from utilizing the other amino acids in proteins. He says this requires people to eat more food to meet their protein requirements, and thus vegetarians are at risk of obesity. Meanwhile, animal-derived protein, he says, contains the amino acids that are most readily used by the body. “Please don’t go on a vegetarian or vegan diet,” he says. “Adults can just about get by if they really know what they’re doing, but for children, it will result in growth deficiencies.”
There is no consensus on this point. Research cited in Pediatric Nutrition in Practice earlier this year finds that vegan children may be “smaller and leaner” but catch up in growth by around age 10. And non-carnivores may choke at Pencharz’s contentions. Erika Krebs, a mother of three vegan toddlers and author of bestselling vegan baby food cookbooks, says her children are all in the 90th percentile of size for their ages. “They’re huge,” she says, “and they’re not fat, either.”
Davis is a vegan himself, though he doesn’t tell others to adopt his same diet. “I’m not big on the terms ‘vegan’ and ‘vegetarian,’ ” he says, although his six-year-old vegetarian daughter does tend to proselytize to her classmates. “I just want people to eat more fruits and vegetables. I don’t know what else I could say. If I can’t convince you that protein is bad for you, I can’t convince you that water is wet.” And repeatedly, insistently, he tells us to stop counting what we consume. “Just stop the count,” he says. Because otherwise, food becomes scientific, and eating isn’t fun anymore.
Looking for more?
Get the best of Maclean's sent straight to your inbox. Sign up for news, commentary and analysis.