Some pretty strange diets are getting lots of buzz. Can they make you healthier? What we learned may surprise you.
Got a health problem? Check the Internet or the next talk show, and you'll find a wacky diet to cure it. "Just stop eating the wrong stuff and start my diet," their creators assert, "and you'll lose your allergies! Overcome fatigue! Live longer! Shed pounds effortlessly!"
To be honest, the theories behind some of these diets are so intriguing (can your blood type really dictate what you should eat, for example?) that it's natural to wonder: Could they work? Especially if you've known someone-maybe it's you!-who's tried one of these diets and is convinced that it helped.
"Unless you're a scientist with courses in biology and physiology, it's hard to sort fact from fiction," says Judith Stern, ScD, professor of nutrition and medicine at the University of California, Davis, and vice president of the American Obesity Association. So we asked the experts. Surprisingly, they gave us reasons why each of the following diets has both hype and hope.
Food-Combining Diet
Two books currently on the market that espouse versions of the old diet idea of combining foods are Suzanne Somers' Eat Great, Lose Weight (Crown Publishing, 1997) and Harvey and Marilyn Diamond's Fit for Life (Warner, 1987).
The Claim Behind It
This type of diet is based on the belief that many health problems occur because we eat foods in the wrong combinations. If you eat the wrong foods together at the same meal, you confuse your body into producing the wrong digestive enzymes (chemicals that break your food into particles that your body can absorb). That leaves undigested food to rot in your intestines-and turn into poisons.
The Promise
If you stop combining the wrong foods, you'll start digesting your meals fully. The result? You'll lose weight, increase energy, and even reverse food allergies.
What You Eat
Eat fruit only by itself-and only in the morning. Eat protein and fat with vegetables, but not with carbohydrates. Eat carbohydrates with vegetables only, never with fat or protein.
The Experts' View
In fact, few foods occur as pure protein, carbohydrate, or fat, as this diet implies. Most foods are a mix, making it virtually impossible to keep components separate. Whole wheat bread, for example, isn't pure carbohydrate-it's also 15% protein and 14% fat.
What's more, it's impossible to confuse your digestive enzymes. Each has just one job to do. In a lock-and-key fashion, each enzyme pairs with the correct substance and severs its chemical bond. "Fortunately, your digestive system is quite capable of making multiple enzymes in just the right mix for what you're eating at the time," says registered dietitian Cyndi Thomson, PhD, a research instructor at the University of Arizona College of Public Health in Tucson.
The Grain of Truth
Strict rules about what-goes-with-what almost automatically limit the size of your meals. This diet emphasizes low-calorie fruits and vegetables (no soft drinks or cupcakes on the "yes" list). Smaller meals and lots of produce are both good ways to lose weight. "That's why you may lose weight practicing food combining," says Dr. Thomson.
What to Watch Out For
Short term, you'll do okay on this diet. But the structure limits your intake of calcium-rich dairy foods while opening the door to foods high in saturated fat. That's bad for your bones, blood pressure, and heart. And if you have a life-threatening food allergy, beware: The only way to control it is to avoid the offending food.
Blood-Type Diet
This diet originated with the book Eat Right 4 Your Type, by Peter D'Adamo, ND (Penguin Putnam Books, 1997).
Another version is The Answer Is in Your Bloodtype, by Steven Weissburg, MD (Personal Nutrition, USA, 1999).
The Claim Behind It
Our different blood types-O, A, B, and AB-evolved in response to the varying environments and diets faced by prehistoric man. Knowing your blood type can tell you what's the best diet (and exercise) for your digestive tract and immune system.
The Promise
If you follow the right diet and exercise for your blood type, you can stay healthy, live longer, and achieve your ideal weight.
What You Eat
Blood type O: Your Stone Age-hunter ancestry means that you need lots of meat and intense exercise, but few grains and little dairy.
Blood type A: You are descended from prehistoric farmers and require a vegetarian diet because you don't produce enough hydrochloric acid to digest meat. Do only yoga or meditation.
Blood type B: Your nomadic ancestry suggests that you need mostly dairy and a little meat, but no chicken and few grains. You need moderate exercise.
Blood type AB: You represent a merging of types A and B. You need a varied diet that emphasizes seafood, dairy, wheat-free grains, and soy foods. Do only yoga and mild aerobics.
The Experts' View
"This is pure pseudoscience," says Dr. Stern. "The blood type theory has never been tested clinically with results published in peer-reviewed journals." One clue that something's amiss: The idea that some people shouldn't get exercise flies in the face of everything we know.
Another red flag: The suggestion that people with type A don't have enough hydrochloric acid. It's true that some people's stomach produces less hydrochloric acid, but that comes with age, not blood type. And the problem with too little hydrochloric acid is that you can't absorb enough vitamin B12, not that you can't digest protein.
And just as a practical matter: How would you feed a family of four with different blood types?
The Grain of Truth
Limited food choices automatically cut calories, so you may lose weight-as long as you can stick with the limited food choices.
What to Watch Out For
No matter what your blood type, this diet sets you up to exclude too many foods. You lose fiber and vitamin E by excluding grains, fall short of carotenoids and phytochemicals when skipping vegetables, and miss out on calcium when you don't do dairy.
Candida Diet
Seems like almost everyone knows someone who's tried this one. You'll find versions of this diet in Candida: A Natural Approach, by Karen Brody (Ulysses Press, 1999) and The Candida Control Cookbook, by Gail Burton (Aslan Publishing, 1996), among many others.
The Claim Behind It
If you're always tired, bothered by allergies, or have recurrent vaginal infections, your entire body may be suffused with an overgrowth of a type of yeast called Candida albicans. If you eat foods that contain yeast, such as bread, or foods that "feed" the yeast-basically, anything containing sugar-you are strengthening the hold of the candida infection on your body.
The Promise
By eliminating sources of yeast and sugar from your diet, you can starve candida out of existence and prevent recurrent vaginal infections, chronic exhaustion, and allergies.
What You Eat
Meat, poultry, seafood, and nonstarchy vegetables are emphasized. This diet comes in three progressively restricted phases. To start with, you cut out sweets, dairy products, breads, crackers, commercial soups, white flour, mushrooms, vinegars, soy sauce, tofu, and apple cider. Later stages banish whole grains, starchy vegetables, fruits, juices, nuts, seeds, beans, herbal teas, and spices.
The Experts' View
In many healthy women, candida can be cultured from the mouth, throat, rectum, or vagina. In addition, about 90% of women will have at least one vaginal yeast overgrowth infection, which is easily cured by an antifungal agent. But about 5% of women face recurrent vaginal yeast infections that relapse after responding to antifungal medication.
In desperation, these women look for nutritional answers, says David Soper, MD, professor of obstetrics and gynecology at the Medical University of South Carolina in Charleston. The fact that recurrent vaginal yeast infections are more common in women with diabetes seems to lend credence to the idea that there is a diet connection. But there's no evidence that eliminating certain foods can cure vaginal yeast overgrowths, Dr. Soper says.
The Grain of Truth
By restricting so many foods-literally from soup to nuts-you're bound to lose weight. Along the way, you may have eliminated a food to which you have a mild allergy.
What to Watch Out For
Although you could get by with this diet for a few weeks (especially if you cheat a little), following it to the letter eliminates so many foods that you'll come up short on calcium, copper, manganese, magnesium, vitamin E, and most B vitamins. Your body deserves better than that!
The "Mayo Clinic" Diet
Before you start this diet, surf on over to the Mayo Clinic Web site at www.mayo.edu/about/mayo diet.html and read their disclaimers. This diet neither originated there nor is it approved by the famed medical center. But does it work?
The Claim Behind It
If you eat only certain combinations of foods, you'll burn more fat. Adding some grapefruit burns fat even faster.
The Promise
On this diet, you can eat as much as you want and still lose weight-permanently.
What You Eat
At every meal, eat half a grapefruit. The rest of your menu is as follows: breakfast-two eggs and two slices of bacon; lunch-salad with dressing, meat; dinner-salad with dressing, meat, and a nonstarchy vegetable cooked in butter. Drink eight glasses of water and one glass of fat-free milk or tomato juice a day. Do this for 12 days, then take 2 days off and eat anything you want. Repeat as needed. Avoid most dairy, starchy fruits and vegetables, and grains.
The Experts' View
"Clearly, there is no science to support this," says American Dietetic Association spokesperson Tammy Baker, RD. "And grapefruit is not magic." Alas.
The Grain of Truth
Why do some people lose weight on this diet? That's easy. A low-calorie menu plan puts your appetite on autopilot for awhile, and restricting food choices (did you notice that there are no desserts?) limits your calories. Men especially seem to find the high-protein diets such as this one filling and satisfying. "But people eventually get bored," says Baker. "And pretty soon you're staring wistfully at your spouse's baked potato."
What to Watch Out For
If you don't choose lean meats, eating all those foods high in saturated fat can raise your risk of heart disease. Plus, calcium is low to absent, notes Baker. Any high-protein diet is hard on the kidneys and should definitely be avoided if you are at risk of kidney disease (if you have diabetes, for example).
Maximize Good Health
Compelling passion is the hallmark of most "miracle diet" creators, and often their enthusiasm is impressive, if not their science. Luckily, following these plans for a short time won't be fatal, and some people say that they do feel better. What's interesting is that each diet has lessons that can make anyone healthier, from cutting down on sweets to eating more low-calorie vegetables to making meals smaller if you need to lose weight.
And since these diets so often result in weight loss, it would be fair to ask this question: What's the harm as long as I can drop a few pounds? "Overweight people think diets such as these can't hurt," says Dr. Stern. "But they can, because they prevent you from seeking a reasonable approach to weight management that you can sustain." Another critical drawback: If you do manage to stick with one of these diets for the long term, you'll be setting yourself up for nutrient deficiencies. Many women already face a calcium crisis-getting only half of what they need-and all these fad diets would make that worse.
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