One reason's it's so hard to tell the difference is that even the worst diets will likely result in weight loss, at least initially. But it does little good to lose weight, experts say, if it comes right back.
"Don't be fooled into thinking it is because of some magical food, pill or potion. What causes weight loss is eating fewer calories than you burn," says Dawn Jackson-Blatner, RD, a spokesperson for the American Dietetic Association (ADA). "Crazy, unbalanced diets cause weight loss because they are basically low-calorie diets."
After a few weeks on an unrealistic diet, dieters usually become frustrated and give up. This leads to feelings of failure that can help send them right back to their unhealthy lifestyles.
"Fad diets not only fail to produce long-term weight loss, they can lead to deprivation, weight gain, and discouragement," says Michelle May, MD, author of Am I Hungry?What to Do When Diets Don't Work."In other words, you are often worse off than before you started."
The Worst Diets Ever
1. Diets that focus on only a few foods or food groups (like the cabbage soup diet, grapefruit diet, strict vegan diets, raw food diets, and many low-carb diets). Beware of any diet that rules out entire food groups. People need to eat from a variety of food groups to get all the nutrients they need, says ADA spokeswoman Andrea Giancoli, MPH, RD.
Yale University's David Katz, MD, author of The Flavor Point Diet, says that while restrictive diets do work initially, they fail over the long haul. You can lose weight on diets that focus on single foods (like cabbage soup), but how much cabbage soup can a person eat? Before long, you grow weary of eating the same foods every day, and cravings for favorite foods lead you back to your former eating behavior.
Keep in mind that all foods can fit into a healthy lifestyle in moderation -- even things like bacon, super-premium ice cream, and chips. And when diets forbid certain foods and dieters envision a life without their favorite treats, those diets usually fail. "Any time you restrict a certain food, it triggers cravings for the forbidden fruit and sets up a restriction-binge cycle," says Blatner.
The Worst Diets Ever continued...
And what about restrictive diets that offer a rewarding "cheat day"? May labels them "absurd."
"It just doesn't make sense to try to be perfect (whatever that is) on Sunday to Friday while obsessing about everything you are going to eat on Saturday," she says.
2. "Detox" diets (like Master Cleanse, the Hallelujah Diet, and The Martha's Vineyard Diet Detox). Extreme regimens calling for procedures like liver flushes, bodily cleanses, colonics, hormone injections, and more are highly suspect, experts say.
"All the flushes and cleanses are pure nonsense, unnecessary, and there is no scientific basis for these recommendations," says Pamela Peeke, MD, chief medical correspondent for the Discovery Health channel. "Your body is well equipped with organs, such as the liver and kidneys, and the immune system, to rid itself of potential toxins and does an excellent job of cleansing itself without needing flushes or cleanses."
3. Diets with 'miracle' foods or ingredients (like supplements, fructose water, bitter orange, green tea, apple cider vinegar). Dieters are always searching for the food, pill, or potion that will help them lose weight, but unfortunately, there are no such miracle ingredients. "No one single food or group of foods eaten together or at a certain time of day has any impact on weight loss," notes May.
Be leery of any plan that recommends a shelf full of supplements, enzymes, or potions (especially if you purchase them from the diet book author or company).
"You don't need expensive supplements," says Blatner. "If you want to take a once daily multivitamin for nutritional insurance, that is fine, but otherwise, we recommend you get your nutrients from food."
4. Fasting and very low-calorie diets (like the "Skinny" vegan diet, Hollywood Diet, and Master Cleanse). Fasting has been a cultural and religious tradition for centuries, and is fine for a day or so, but fasting for weight loss is counterproductive, Giancoli explains.
"When you ... consume too few calories, your body thinks it is starving and adjusts the metabolism," she says. "But when you go back to eating normally, your metabolism doesn't readjust and therefore you need fewer calories than before -- otherwise known as the yo-yo syndrome."
What's worse, weight loss during a fast is usually a combination of fat, fluid, and muscle, but the pounds regained will probably be all fat. Not convinced yet? Giancoli says you won't feel good, nor will you have much energy to be physically active while fasting.
And what about very low-calorie diets? Blatner say that diets promising losses of more than a half to 1 pound per week are simply not realistic.
"When you see diet books touting 5, 10 or 15 pounds in a short period of time, it is unrealistic," says Blatner. Depending on how much you have to lose, you may experience some initial water loss. But over time, weight loss averages out to around a pound per week, she says.
5. Diets that sound too good to be true (like The Weight Loss Cure 'They' Don't Want You to Know About.) If it sounds too good to be true, it probably is. Diet plans that claim to have a "secret," that make dramatic statements against respected health authorities, or make recommendations that contradict those of scientific organizations are suspect.
Finding a Diet That Works
There is no such thing as one size fits all when it comes to diet plans, and it's key to find one that fits your lifestyle. The best diet is one you can safely and realistically stick with for the long term, plain and simple.
"It should be flexible enough to fit into your real life and should encourage healthier eating by focusing on balance, variety, and moderation" says May. "I encourage my patients to enjoy eating the foods they love every day, mindfully and in moderation."
In fact, the best "diet" may not be a diet at all, says Katz.
"Forget about 'dieting' and instead, think about strategies to satisfy your hunger for fewer calories," he says. "Eating more fruits, vegetables, whole grains, and lean protein can help manage your appetite."
Blatner recommends using diet books as a loose template for tips, strategies, and behavioral ideas. Or save your money and follow the three-step approach she uses with her own weight loss clients:
Take inventory of what you're doing now and identify your "weakest link." "Most people know immediately where they are vulnerable -- 3 p.m. snacking, monster portions, too much alcohol, (an) insatiable sweet tooth, or snacking all day long," she says. Katz suggests trying to identify what led to your weight gain and address it. For example, if you overeat because of stress, consider a stress management course. Develop a strategy to address areas where you're vulnerable so you can set yourself up for success.
Identify one to three small changes you can make right now in your diet and exercise habits. "Even though they want quick results, this method has proven to be safe, effective, and sustainable long term," Blatner says.
Reassess in a few weeks to see whether your changes are working; then make a few more small changes. "It takes about 12 weeks for you to see progress, and that is about the time you should incorporate a few more changes so you keep pushing the bar," Blatner says.
HEALTH IS WEALTH ..... STAY HEALTHY