Just because a girl in your office has a cousin whose friend lost 10 pounds in four days with a diet doesn't mean her esoteric diet will be safe, effective, and sustainable for you. To put things in perspective, Cosmopolitan.com asked Charlie Seltzer, M.D., a weight-loss specialist based in Philadelphia, Pennsylvania, to debunk the Internet's craziest diets and rate them from 1 (try it!) to 10 (totally nuts).
Rules: No solids. Some programs entail drinking six or so ready-to-drink fruit and vegetable juices throughout the day. There are lots of DIY iterations: Victoria's Secret angel Adriana Lima has said she sticks to an all-liquid diet before fashion shows. For nine days prior, she drinks protein shakes made from powdered egg and one gallon of water per day.
Rationale: Because this super low-calorie, produce-based diet prohibits all the solid foods you're used to eating, it helps you eat fewer calories without having to navigate tons of complicated rules. This creates a calorie deficit that promotes weight loss.
Reality: "It might sound cool to lose 10 pounds in three days, but weight you lose on a juice cleanse tends to be water weight from your muscles, not fat," Dr. Seltzer explains. "Afterward, your body won't look much different in the mirror, and you'll gain it all back from just looking at a bagel," he adds.
Crazy Scale: 11/102. The Charcoal Cleanse
Rules: You drink juice containing activated charcoal to your regular diet.
Rationale: Your body can't absorb activated charcoal, so it passes through your digestive system untouched. Because it clings to toxins in the body, it removes impurities like pesticides and any unhealthy stuff found in non-organic or processed foods. Advocates say it improves the skin, boosts digestion, and enhances organ functioning.
Reality: "You think you're taking toxins out of your body, but charcoal doesn't pass through your whole body—just through your intestines, where it can bind to nutrients and suck those out," Seltzer explains. "Our bodies are pretty good at processing toxins, and your chances of dying from toxins in food are lower than your risk of dying from being obese. If you want to decrease toxins in your body, don't eat them in the first place by avoiding processed foods," he adds.
Crazy Scale: 12/10
Rules: Designed to promote optimal health, you eat a vegan, whole-grain-based diet plus some beans and vegetables. Some versions allow fruits, fish, seeds, and nuts (but only once or twice a week) and strong spices are discouraged. So no animal products (including dairy or eggs) or processed foods.
Rationale: Brown rice and other whole grains contain the perfect balance of yin (stimulating) and yang (stagnating), so a diet largely based on these foods is supposed to promote wellbeing and longevity.
Reality: It's not sustainable and can cause some nutritional deficiencies. "Most people can't do it," Dr. Seltzer says. "The stress associated with trying to follow a diet like this can offset the benefits. We're omnivores and supposed to eat meat," he adds.
Crazy Scale: 6/10
Rules: Designed to promote weight loss, this diet entails eating upward of 16 jars of baby food per day instead of regular meals and snacks. You can eat one regular meal every day.
Rationale: It creates a calorie deficit that promotes weight loss, rids the body of toxins, and helps you breaks bad habits, according to Tracey Anderson, who's been credited with creating the program.
Reality: While baby food is minimally processed (pro!), "it's a gimmick. If you look at people who have healthy bodies, no one will tell you they eat a baby food diet. It's infinitely ridiculous."
Crazy Scale: Infinity/10
Rules: You eat everything while wearing blue-tinted glasses.
Rationale: Based on the idea that red/yellow-colored foods are the most palatable (think: meat, French fries, ripe produce, etc.), this diet is designed to make your food look less appetizing. In theory, this makes you eat less.
Reality: "It doesn't sound right to me," Dr. Seltzer says. "But if it makes people leaner, there's no downside." Except being seen in blue shades at brunch, lunch, and dinner.
Crazy Scale: 10/10
Rules: You drink extra-light olive oil or flavorless sugar water between meals.
Rationale: Eating a variety of flavorful foods stimulates hunger and makes you gain weight. If you consume bland foods, you fend off hunger without inducing food cravings, so you end up eating less and losing weight.
Reality: "Not a bad idea," Dr. Seltzer says. "For some people, exposure to a greater variety of food stimulates the appetite. For others, though, eating the same thing every day makes you bored and crave more foods. Success would probably depend on the person. I wouldn't be offended if you tried eating bland foods at meals. But I'd use whey protein instead of olive oil between meals, because it will satisfy your appetite with fewer calories."
Crazy Scale: 3/10
Rules: Cover your nose so you can't smell while you eat.
Rationale: It blunts your sense of taste, which helps you focus on your actual appetite and stop eating when you're full.
Reality: "Smell does drive appetite and food intake, but you're going to go out to dinner and cover your nose? No normal person will do that in the long run," Dr. Seltzer says.
Crazy Scale: 7/10
Rules: You only eat during a daily eight-hour window (i.e., between 9 a.m. and 5 p.m. or 11 a.m. and 7 p.m.)
Rationale: Intermittent fasting appears to moderate the circadian rhythm and ultimately boost metabolism to fend off weight gain, according to human and animal studies. Also, reducing the amount of time you spend eating can help you save up calories so you don't have to deprive yourself when you do get to indulge.
Reality: "There's no evidence that eating breakfast or eating every three hours improves your metabolism, so for people who don't get hungry in the morning, this variation on fasting is actually maintainable," Dr. Seltzer says. "Just don't try it if it makes you hungry—that's not a good way to live and it's not maintainable for you."
Crazy Scale: 1/10
Rules: Every morning, you eat a breakfast that's high in protein (i.e., about 45 grams, depending on your weight) and high in carbs (i.e., 60 grams) plus dessert, such as chocolate, a doughnut, a cookie, or cake.
Rationale: Extra protein and carbs fend off hunger, and eating treats in the morning can curb your sweet tooth later on.
Reality: "This is based on research, and it's solid," Dr. Seltzer says.
Crazy Scale: 1/10
Rules: You eat five pints of special ice cream a day. (The brand-name version costs $199 (P8,000+) for three days. Unlike Ben and Jerry's, this diet ice cream is made from coconut cream and honey.)
Rationale: It controls your calories for a deficit that produces weight loss. And you get to eat ice cream all day. (Don't ask questions.)
Reality: "Any calorie deficit will create weight loss—but it can also cause a nutritional deficiency. Still: What do you do when you go out to dinner? You can't eat ice cream for the rest of your life. People are too concerned with getting weight off and not what happens after it comes off," Dr. Seltzer says.
Crazy Scale: 10/10