High-protein diets, America’s latest food fad, are like an overstuffed deli sandwich – some healthy nuggets here and there surrounded by a fair amount of unhealthful baloney.
That, at least, is the view of mainstream nutritionists, many of whom feel that Americans hooked on books like “The Zone,” by Barry Sears, “Protein Power,” by Drs. Michael and Mary Dan Eades, and “Dr. Atkins’ New Diet Revolution” are being fed a mixture of truths, half-truths and totally unproven assertions.
For years, nutritionists have urged us to eat less fat and more complex carbohydrates so that we’ll have fewer heart attacks and be generally more slim, healthy and vigorous.
That’s still a basically sound message. But somewhere along the line, it’s been twisted by some into a license to eat unlimited amounts of pasta and potatoes, with obvious results at the waistline.
But there’s a less obvious result of this love affair with carbo, too, a feeling on the part of many that “carbohydrates have failed them,” says Larry Lindner, executive editor of the monthly Tufts University Health & Nutrition Letter.
For that reason, he says, many people are hungry for any self-appointed guru who seems to have a better message.
The trouble is, switching from a carbo-heavy diet to one loaded with protein is not necessarily better. In fact, some parts of the high-protein message are not only unsupported by any scientific evidence but may even be dangerous.
To sort out what’s valid and what’s not, we consulted nine leading nutritionists, as well as the Harvard Health Letter of January 1997 and the Tufts nutrition letter of May 1996.
Their consensus is that at least some high-protein diets are based on a number of myths. Such as:
Myth No. 1. Americans do not eat enough protein.
This is unlikely, except for frail old people, poor people who do not get enough calories every day, and perhaps some elite athletes who put huge demands on their bodies.
Sears acknowledges that most Americans “probably consume adequate protein in the course of a day, but not at every meal.” But in the next breath he contends that because people have been told to shun fat, which often comes in the same foods as protein, many people on diets are protein-deficient.
A Swampscott biochemist, Sears runs a biotech company called Eicotech, Inc. He is not a nutritionist and complains that real nutritionists “have no command of the literature.” He recommends reducing carbohydrates to 40 percent of calories, boosting protein to 30 percent and keeping fat at the level of 30 percent or less that nutritionists suggest.
Men, he says, need 100 grams of protein a day, and women, 75, on average. To get that, you’d have to eat 14 ounces of steak or a 10-ounce steak plus three servings of milk, yogurt or cheese every day if you’re a man and 10 ounces of steak or a 6-ounce steak plus three dairy servings if you’re a woman.
By contrast, the US Department of Agriculture and the American Dietetic Association recommend diets that provide 15 percent of calories from protein, 55 to 60 percent from carbohydrate and up to 30 percent from fat.
This translates to about 75 grams a day of protein for men and 65 for women, says Dr. George Blackburn, medical director of the center for the study of nutrition and medicine at the Beth Israel Deaconess Medical Center. To get this, you’d need to eat 6 ounces of steak or the equivalent for a man, or 4 ounces of steak or the equivalent for a woman. And unlike Sears, Blackburn and other nutritionists advocate getting lots of protein from grains and vegetables like beans and lentils.
The bottom line is that if you eat enough calories – 2,000 a day for women, 2,500 for men – you’re almost certainly getting plenty of protein because many foods contain a mix of all three basic macronutrients: fat, carbohydrate and protein.
Myth No. 2. Eating too many carbohydrates leads to hyperinsulinemia – chronically high levels of insulin.
This is one of those half-truths. The idea, according to the high-protein gurus, is that eating tons of carbo makes the body pump out too much insulin, the hormone that helps transport glucose from carbohydrate breakdown into cells for energy.
Because insulin does increase trigylcerides (the fat molecules that wind up as plaque on artery walls) and lowers HDL, or “good cholesterol,” the high-protein gurus contend that too much insulin is the cause of many health troubles.
This notion contains “just enough of a kernel of truth to mislead people,” says Dr. Dean Ornish, president of the Medical Research Institute in Sausalito, Calif., who adds that none of the high-protein advocates has “published a single study in any peer reviewed journal about anything, much less the benefits of their recommendations.”
Dr. Walter Willett, a nutritionist at the Harvard School of Public Health, agrees with Sears on some of the basic biochemistry.
“On that note, he is right. There has been this false idea perpetrated by nutritionists that you can load up on as many carbohydrates as you want and that it’s good for you. That’s not true,” Willett says.
But insulin does not, as protein gurus say, promote storage of glucose as fat, provided you burn more calories than you eat.
Nor is it true, as the “warning” on Sears’ book jacket says, that you should avoid fruits like bananas, cranberries and orange juice. While no one recommends a diet full of simple carbohydrates – sugar and pasta – nutritionists do advocate eating complex carbohydrates, including grains and fruits, in part because they provoke a nice, gradual secretion of insulin.
Dr. Gerald Reaven, emeritus professor of medicine at Stanford University School of Medicine, an insulin specialist, dismisses Sears point blank: “Nothing he says is right.”
In general, nutritionists say, you build up too much insulin if you are insulin-resistant – if your cells no longer respond to normal levels of insulin and your body makes more to compensate. But this condition affects only about 15 percent of the population and usually develops if you eat too many calories overall, not simply too many carbohydrates.
In short, insulin is not the monster hormone it’s portrayed to be, and without it you’d wind up with diabetes.
Myth No. 3. People are overweight because they are hyperinsulinemic.
Wrong. People are overweight because they eat too much and exercise too little, says dietician Chris Rosenbloom of the American Dietetic Association. There is no evidence that hyperinsulinemia causes people to be overweight and plenty of evidence that being overweight increases your risk of hyperinsulemia.
Myth No. 4. Carbohydrate is the enemy.
Not true, provided you don’t take in more calories than you expend. Among other things, carbohydrate is crucial for production of the brain chemical serotonin, which is necessary for mood maintenance and sleep.
Myth No. 5. Eating protein will not raise insulin.
Wrong. It’s true that carbohydrates raise insulin most dramatically, but protein can raise it, too. (Fat does not.) In reality, most foods are a mix of all three, so insulin goes up – as it should – after a meal.
Myth No. 6. Excess protein is not stored as fat.
Not true. Excess calories from any food are stored as fat.
Myth No. 7. A fat calorie is different from a protein calorie and from a carbohydrate calorie.
Wrong. A calorie is a calorie.
Myth No. 8. High-protein diets work because people change what they eat.
Not likely. If a high-protein diet works for you, it’s probably because you’re consuming fewer calories by passing up excess carbohydrates. On a high-protein diet, a woman may take in 1,300 calories a day and a man, 1,700 – far below what most people eat.
Myth No. 9. Ketosis is good for you.
Wrong. Ketosis is the state achieved if you are starving or eating almost no carbohydrate, but lots of protein and fat. The body then burns dietary fats and proteins for energy.
In their book, the Eades say ketosis is “not at all” dangerous unless you’re diabetic. In Dr. Robert Atkins’ book, he says ketosis as an “extremely desirable state to be in.”
This is misleading. Ketosis is a sign that the blood is becoming too acidic. To combat this, the body then takes calcium from the bones, which raises the risk of osteoporosis. In fact, the Nurses’ Health Study showed that women on higher protein diets had a higher risk of bone fractures. Ketosis can also damage the kidneys, cause bad breath and trigger irregular heart rhythms that can cause sudden death.
Myth No. 10. Don’t worry about fats, which often, as in a juicy steak, are present in foods that contain lots of protein.
This gets tricky. Nutritionists say we should get at most 30 percent of calories from fat, and Ornish pegs it at 10 percent. But the real issue is what kind of fat you eat, and you can eat a lot if it’s unsaturated stuff like olive or canola oil.
The basic problem is, if you want to reduce carbohydrates, you have to raise either fats or proteins, says Willet. “And I think it’s safer to raise fat, as long as it’s the right type.”
Instead of pushing protein up to 30 percent of calories, he says, you can allow unsaturated fats to comprise 40 percent of your diet. The result is the Mediterranean diet, one of the world’s most healthful, with 30 to 40 percent fat, 20 percent protein, and the rest carbohydrate.
There’s one final reason to take a dim view of some high-protein diets: They can get a little weird.
Although in conversation Sears insists he is just advocating the kind of balanced diet that everybody’s grandmother used to recommend, in his book, he suggests snacks like a half cup of Haagen-Dazs ice cream with four ounces of turkey as a chaser.
Did you ever know a grandmother to suggest a snack like that?
Sources for story
The following nutritionists were interviewed for this column:
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Dr. George Blackburn, medical director of the center for the study of nutrition and medicine at Beth Israel Deaconess Medical Center.
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Johanna Dwyer, director of the Frances Stern Nutrition Center at Tufts University.
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Alice Lichtenstein, nutritional biochemist, Tufts University.
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Larry Lindner, executive editor of the Tufts University Health & Nutrition Letter.
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Dr. Dean Ornish, president of the Preventive Medicine Institute in Sausalito, Calif.
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Dr. Gerald Reaven, professor of medicine (active emeritus) at Stanford University School of Medicine.
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Chris Rosenbloom, registered dietician, spokesperson for the American Dietetic Association.
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Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard School of Public Health.
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Dr. Richard Wurtman, director of the clinical research center at the Massachusetts Institute of Technology.