July/August  1999   

Diet mania
Making sense of the new diet regimens:
The Zone, Blood Type, Mediterranean, Ultra Low Fat, Vegan, Body Type
By Barry Burnett, M.D., M.P.H.

What's for dinner? It's the universal question, the one at the end of each long day. The answer is obvious: anything we want. Well, anything within reason: affordable, preparable, available, something we grew up on, something once served with love. The choices narrow. Then the final condition: something that is . . . healthy. How do you know what will be healthy for you, or for each of your family members?

Wasn't there an article in the paper last week? Protein's good now, and fat's OK, or maybe not. Those scientists can't make up their own minds, much less yours and mine. If we heeded every warning there'd be nothing left! And then there's that blood type diet, and others, too—a new one in the news each day. Surely, you think, one of them will sustain my energy all day, make me feel better, and help me drop a few pounds. Perhaps you think with all the diet gurus disagreeing about proteins and fats and even algae, you might as well eat whatever you like.

CHASING THE IDEAL

People have been hammering themselves about diet and health forever, but the real guilt didn't hit until the ’60s, when the men and women in the white lab coats took over. It began with the first firm connections between blood cholesterol and heart disease. By the mid-’80s, saturated animal fats had been identified as the culprit for raising blood cholesterol. Out of that came the first of the medically perfect diets, popularized most recently by Dr. Dean Ornish and based on the traditionally healthy fare of Asia: extremely low fat, lots of fruits and grains and vegetables and few, if any, animal products.

Despite the research backing it up, the problems with that diet—most of all the difficulty in persuading anyone who hadn't had a heart attack to try it—proved a fertile ground for controversy, and out of that came the high-protein diet.

What distinguishes each diet is its emphasis on different macronutrients—the three main types of food we take in and metabolize, in other words, carbohydrates, protein, and fat. The Asian diet, by virtue of being low in both fat and protein, winds up being mostly carbohydrates.

The one who led the protein charge was Barry Sears, Ph.D, with the Zone diet. He argued that high-carbo intake raises insulin levels, leading to higher triglyceride levels and more heart disease and obesity. To reduce all of that, he recommended, eat more protein—lean if possible, but (as in the more recent Paleolithic or caveman diet) meat and lots of it. All the public seemed to hear were the two buzzwords: meat, which they liked, and obesity, which they didn't.

When the approach is extreme, as with this year's Sugarbusters diet, the body's fat is broken down into keytones, which can dangerously affect heart rhythms. Liz Applegate, Ph.D., author of Eat Your Way to a Healthy Heart, notes that even with the Zone diet, "some young athletes and elderly patients have trouble with endurance, and are concerned about their intake of associated animal fats."

But others, using the diet in moderation, say they feel better than ever before. Scientific data on their health outcomes is still years away. Most importantly, the popularity of these carnivorous diets again raises the question: What good is any healthy diet if no one likes it enough to stay with it?

Which brings us back to American's third and favorite macronutrient: fat. Good fat is embodied by the Mediterranean diet. While previous diets were being publicized and tried, researchers were trying to discover why oil-loving Greeks and Italians were breaking the rules and living so long. According to University of Colorado nutritional epidemiologist Tim Byers, MD, MPH, "There's been an overemphasis on total fat at the expense of what type of fat to eat. Even some diets of 35-40 percent fat calories appear to be heart-healthy."

Last year's Lyons Diet Heart study results went a long way to proving the value of a diet high in monounsaturates (olive and canola oils), with lots of unprocessed carbohydrates and modest amounts of meat and dairy. Not only did it reduce heart disease, but it was enjoyable enough that almost all the study's subjects had stayed with it four years after the first phase of the research ended. Interestingly, their triglyceride and blood sugar levels were somewhat elevated, as Sears would have predicted, although they had less heart disease and cancer anyway.

That doesn't mean that we should go hog-wild with the good fats. To quote Dr. Byers again,"Given the nationwide epidemic of obesity, the best way to change the ratio of saturated to monounsaturates is by decreasing animal fats."

PERSONALIZED DIETS

Solid evidence now supports both the Asian and Mediterranean-model diets, and at least a moderate amount of protein. Sounds like the 'perfect' diet is still pretty much up for grabs. What if there isn't one diet that's right for everybody? How do you tell which one is for you?

You could freely follow your body's personal inclination—the undiluted dictates of taste and hunger. But that's what most of our parents tried in the flush of post-war affluence, and look what it got them: big bellies and hard arteries. Or you could rein yourself in a bit with some palatable combination of the diets or look for some systemic approach to customize a diet, such as the new blood and body types diets.

Peter J. D'Adamo's Eat Right For Your Type has made the biggest recent splash. Steeped in the Naturopathic tradition of helping patients find unique pathways to health, it's based on his personal observations of how different patients responded to particular diets. He concludes that blood types determine how the rest of the body is affected. He gives his recommendations an interesting anthropological spin: those with type O, which he claims is humankind's oldest blood group, do best with a cavewoman's meat-rich protein diet; members of the historically more recent type A group thrive on the low-fat, vegetable-rich diet of the first agrarian peoples that settled the Middle East; the still-later B-types, first seen in Europe, benefit from a Mediterranean diet with more dairy; and the modern, interbred ABs do well on something in between. The above descriptions, by the way, are greatly simplified. Each of the four diets (which fish, which vegetable, which tea to drink) are manifoldly complex.

There are a few hitches, according to Naturopath Greg Kelly, D'Adamo's partner, who says, "Almost all of us are blood type A and O." As far as the history, Jack Kelso, Ph.D. (emeritus professor of anthropology and author of seminal research on blood type and diet) notes that type A, not O, is historically associated with meat-eaters. Moreover, according to hematologist Lori Jensen, MD, "The red blood cell antigens that determine what type of blood you have are most definitely not found on the other cells in the body." All of that sounds pretty damning, but, as Kelly points out, "The clinical observations came first and the historical, anthropologic and scientific interpretations later."

The big thing, he says, is: "Don't get locked into any one supposedly perfect diet, but use your innate wisdom to find the things that work for you. Your blood-type diet can be used as a road map for the future." He says that, if the type is right, the carnivorous can switch to a vegetarian diet (and vegans learn to gnaw that steak bone) with remarkable ease. Ultimately, he concludes, everything is about results in life. He recommends the curious try it for a while and measure how it works for themselves.

More than a few swear by the blood type diet. But nutritionists’ comments range from "comical" to "totally weird." In Dr. Applegate's view, "The blood type diet is a novel, unusual diet, and with any novel diet people are more apt to follow that program initially and lose weight. It spins them around 180 degrees, and that much change is intriguing to people. Sometimes their common sense comes through over time."

Dr. Elliot Abravel's body-type diet was originally pitched as a weight-loss program. It also aims to identify the healthiest diet for you. Four types for women, and three for men, are based on body habitus: classifying the shape or appearance of the physical form. The theory is that each shape has a different dominant hormone, demanding (and then enthusiastically laying down the fat with) its own class of foods. The pituitary-dominants love dairy and tend, seal-like, to lay it down all over; the thyroids go for carbohydrates to build thick thighs; adrenals crave meat and eggs to pad a big gut; and the exclusively female gonadal group reaches for the oils to provide that extra cushioning where they sit. The advice, in general, is for each type to avoid their natural area of excess, but there are a few unusual recommendations: lots of eggs for thyroids, organ meats for pituitary-types and caffeine for the adrenal crew. Practitioners who use his approach, notably Boulder Naturopath Johanna Riley, do find that their clients naturally fall into different body types, and that the associated diets Abravanel recommends have helped some members of each type feel better. She says that some of us "might be able to eat normally. But most people are out of balance because the world is out of balance. Other countries have a culture that teaches them how to eat." Saturated fat is not the issue, in her opinion, because, she says, "Cholesterol is from stress, not from diet."

If that sounds unscientific, that's because it doesn't fit with most of what we know about cholesterol. But the 'typing' diets do try to account for the individual variations that are everywhere else in human life, and they sidestep the conflicts of all the different expert recommendations and research findings.

But why can't we have it both ways? Why can't we have personalized diets—ones that fit who we are—and have them make medical sense, too?

PUTTING IT TOGETHER:

A few guidelines may help:

1) Freedom of Choice. As Marion Nestle, PhD, MPH, and department chair of nutrition and food studies at New York University points out about the Asian and the Mediterranean diets, "Both approaches seem to work well, given the longevity of the Japanese and the Greeks even now." And while the high-protein approach doesn't have many scientific fans, with moderation and an eye on keeping meat's saturated fats to a minimum (lean cuts, free-range beef, no chicken skin, etc.) that may work for some, too. The wonderful thing about the blood- and body-type diets is that they open up a sense of choice, and if the apparently arbitrary nature of assigning those diets doesn't ring true, at the very least they remind us of the range from which we can choose. The notion of one diet being right for everyone seems unlikely.

2) Basic rules. Aside from the world's cuisine providing "a wide variety of healthy choices," according to Byers, "there are a few basic rules as well: less saturated fats, less calories overall and more fruits and vegetables—especially vegetables." These are the common elements that turn up across studies and across cultures, and are far more important (if less newsworthy) than the hot new diet finding of the week.

3) Avoid the extreme. Anything brand new is just plain unlikely, no matter how bright and shiny and novel it may be. Humankind has been gathering food, eating and enjoying it an awfully long time, long enough to try out almost everything. Diets should both be rooted in history and make sense in terms of what we know right now. It's no surprise that quick-weight-loss fad diets tend to be the most extreme—starvation is not a particularly kind thing to do to your body.

4) Have Fun. It's your palate and your pleasure, and whatever you decide is healthy will only make a difference if (as we saw with the Mediterranean diet study) you love it enough to stay with it. You can give it a couple of weeks, or, as Kelly recommends, "a full four seasons." After that, only you can decide if it's working in the context of the rest of your life. Ask yourself if you feel deprived. It also wouldn't hurt to check your blood lipids (total cholesterol, HDL, LDL and triglycerides) after a few months, just to make sure you're not flaunting too many of the basic rules.

What lies in the future? Byers sees medically prescribed diets, based on individual biochemical testing and genotyping for risk assessment, adding, "they're at least five years away. Anything before that will probably be bogus."

In the meantime, advises Applegate, "We need to get back to the dining table. Enjoy the people you're with and the food you eat. Calm down about individual foods and look at the big picture. We're all individuals and need to make wise choices for ourselves, in terms of not only diet, but also activity and stress. We need to mellow out."