Diabetes and the Risk of Fad Diets

Plenty of popular gimmicks promise quick weight loss, but for people with diabetes, fad diets can be dangerous.

Medically Reviewed by Louise Chang, MD on February 10, 2006
From the WebMD Archives

Remember Jared, the Subway Diet guy? He lost 245 pounds eating subs and not much else, every day for a year.

If you want to lose weight, there are plenty of fad diets and gimmicks out there. Think: The Zone, Sugar-Busters, or the cabbage soup diet. Sure, you can lose weight -- but if you have diabetes, you might also put your health at risk.

"You can cut carbs, eat grapefruit, stand on your head a few days -- anybody who sticks to any diet will lose weight," says Luigi Meneghini, MD, director of the Kosnow Diabetes Treatment Center at the University of Miami School of Medicine.

Problem is, once the diet's over you're likely to return to those bad dietary habits that got you in trouble in the first place.

"Most people look at diets as a temporary measure to lose weight," Meneghini tells WebMD, "but they're not a real plan for changing unhealthy dietary habits."

The key to dieting for everyone -- whether you have diabetes or not -- is keeping the weight off and sticking to healthy eating habits.

Fad Diets & Diabetes: The Special Risks

For people with diabetes, there's another caution -- fad diets can cause downward spikes in blood sugar, says Cathy Nonas, MS, RD, a spokeswoman for the American Dietetic Association and a professor at Mount Sinai School of Medicine in New York City.

"Reducing your calories, even at one meal, will affect your blood sugar," Nonas tells WebMD. "If you're taking medication that's also lowering your blood sugar, you will need to reduce that medication. You will need to monitor your blood sugar more often, depending on the severity of the diet and how calorie-restricted it is."

A fad diet can also increase cholesterol and blood pressure levels -- creating an especially high-risk situation for someone with diabetes, says Tara Gidus, MS, RD, a national spokeswoman for the American Dietetic Association and a private-practice nutritionist in Orlando, Fla.

"Diabetes can affect a number of systems in the body," Gidus tells WebMD, "putting you at higher risk for heart disease and other chronic health problems -- life-threatening health problems."

You simply have to be more savvy about your diet, says Gidus. A person with diabetes "cannot regulate blood sugar in the same way as a person without diabetes. There is more risk of complications. A fad diet can increase that risk."

Diet Fads: What's Good, What's Bad

Here's a sampling of some popular diets, and experts' opinions of them:

High-Protein Diets

The famous Atkins high-protein/high-fat diet encourages eating red meat, full-fat cheese, chicken, bacon, fish and shellfish, butter, mayo, and olive oil. With Atkins, carbohydrates are severely restricted during the two-week induction period - which is intended to cause ketosis, a condition in which the body burns its own fat for fuel.

"Ketosis is not good for anyone, but especially if you have diabetes," Gidus tells WebMD. "Most people get into hypoglycemia before they even get to ketosis.

Atkins is "way too low in carbs," says Gidus, and the diet's high cholesterol and fat intake is another big problem, increasing the risk of heart disease. In addition, all that protein makes your kidneys work harder, which can worsen existing kidney problems.

"I definitely advise diabetes patients to stay away from Atkins," says Gidus.

Low-Carb Diets

Cutting carbs is a strategy for many dieters, and it's the cornerstone of the South Beach diet.

Like the Atkins diet, South Beach begins with a two-week induction period meant to trigger ketosis.

Simple carbs are forbidden, but "good carbs" are encouraged -- whole grains, vegetables, lean protein (fruits can be phased in after the induction). Unhealthy fats (including fatty meats) are banned. Most importantly, the diet does not leave out any major food groups.

"The South Beach diet is relatively healthy, since it just eliminates simple carbs," says Meneghini. "Many of my patients have discussed it with me. … For them, cutting those carbs might be an easier way of reducing overall calorie intake than reducing portions."

The first phase of South Beach is "too strict for diabetics," says Gidus. He recommends they avoid it. "But Phase Three, maintenance, is the type of food plan that I generally recommend … there's some good information there."

Carb-Controlling Diets

Glycemic index is a concept of controlling blood sugar based on the types of carbs you eat.

  • High-glycemic-index foods -- such as white bread, rice, mashed potatoes, and most cold cereals -- cause a quick spike in blood sugar, so there's a burst of energy, then hunger again.
  • Low glycemic index foods -- fruits, vegetables, beans, and whole grains -- cause levels to rise more slowly and last longer, so there's less hunger for a longer period.

"Glycemic index diets are very confusing, and they're not backed by the American Diabetes Association," says Gidus.

"There are several phases of these diets, where you're restricted to eating all green, all yellow, or all red foods," Gidus adds. "Mixing in other foods totally throws the whole thing off, but nobody eats just one food at a time -- which is why the ADA does not endorse it. You need to be aware of total carbs, that's what the science shows is most important."

Meal Replacement Diets

Meal replacement products -- like Slim-Fast diet shakes and snacks -- are another weight loss strategy.

The Slim-Fast plan involves eating six small meals/snacks every day -- with three involving Slim-Fast products. The rest of the day, you're on your own to choose healthy meals. No foods are forbidden; you can still eat your favorites. However, lean protein, fruits, and vegetables are emphasized.

The products take the guesswork out of portion control, says Nonas.

"A person with diabetes can do a Slim-Fast diet," she explains. "What's important is that you're eating healthy meals, eating smaller portions, eating fruit and vegetables, and getting some exercise. You also need to monitor your blood sugar."

One word of caution: "You must take into account the number of carbs in those products," Gidus tells WebMD. "You may need a shake plus a banana. Also, just because something is low-carb doesn't mean it's good for you. There's the danger of going too low."

Also, if you're eating six small meals a day -- instead of three - adjust your insulin or medications to allow for this change. That's why discussing any of these diets with your doctor is an absolute must.

Extreme Liquid Diets

These are all-liquid meal replacement products - generally, 800 calories or less for daily intake.

For these diets to be safe, you and your doctor must closely monitor your blood sugar and fine-tune your insulin and medications. Using the products can result in an average total weight loss of 44 pounds over 12 weeks. In the long run, that weight loss can improve obesity-related medical conditions like diabetes, high blood pressure, and high cholesterol. But in the short run, these diets are risky for people with diabetes.

"Generally, with these liquid diets, four 200-calorie shakes a day are allowed -- and that's all," says Gidus. "But those shakes aren't just low-calorie, they're also low-carb. When you add up the carbs, it might not be enough for you. I don't recommend those diets for people with diabetes."

Also, liquid diets don't teach you about healthy eating habits -- which is the most important thing to learn.

Weight Loss: Doing It Right

Fad diets are easy to identify: They often blame particular hormones for weight gain, suggesting that food can change body chemistry.

Trendy diets also often tout or ban a particular food. And their advice is not in line with major health advisors like the American Heart Association, American Dietetic Association, or the Surgeon General.

If you are overweight and have type 2 diabetes, it's important to change bad habits that promote weight gain. Meneghini's keys to healthy weight loss: strive for a balanced diet and more physical activity. "Small changes over time will give you very good results."

And remember, a healthy diet does not exclude any of the five food groups -- grains, vegetables, fruits, milk, meat and beans, and oils -- ensuring you get essential vitamins, minerals, and protein. Because fad diets severely restrict major nutrients, they can lead to serious health problems later on.

"For some people, making note of the high-calorie junk food you've been eating, then stop eating it, is all you need to do," Meneghini tells WebMD.

This can include alcohol. "If you have diabetes, you have to be careful about alcohol," advises Gidus.

Gidus also recommends avoiding appetite suppressants. "Most people don't overeat because they're hungry. They eat for social and emotional reasons. They have bad habits."

The Bottom Line on Fad Diets

"If you're a diabetic, you need to be more savvy, more aware, and not fall into these fads," Gidus says. "They can be more damaging to your health than for the average healthy person."

As for Jared, the Subway Guy, "I think what he did was great, considering he did it on his own. He found a plan that worked for him," Gidus adds.

"Did he get enough calcium and vitamins? I don't know. But it was not terribly unhealthy -- vegetables, lean meats, bread. It's all about finding whatever will work for you. And when he lost all that weight, he reduced risk of life-threatening chronic diseases."

WebMD Feature


SOURCES: Luigi Meneghini, MD, director, Kosnow Diabetes Treatment Center, University of Miami School of Medicine. Cathy Nonas, MS, RD, spokeswoman, American Dietetic Association; professor at Mount Sinai School of Medicine in New York City. Tara Gidus, MS, RD, national spokeswoman, American Dietetic Association; private-practice nutritionist in Orlando, Fla.

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