5 Crash Diets You Should Never, Ever Try

Beyoncé purportedly used it to lose weight for her role in Dreamgirls, but this quick-fix diet—which involves drinking nothing but a concoction of lemon juice, maple syrup and cayenne pepper for days at a time to drop pounds—can be dangerous. (In fact, Stanley Burroughs, the man who created it, was convicted with involuntary manslaughter when a patient died while doing the Master Cleanse under his care. Yikes.)

Eating cabbage soup, veggies and plain chicken for a week straight is as boring as it sounds (and don’t even get us started on the gassiness). In the grand scheme of crash diets, it isn’t the worst, but we recommend incorporating a better variety of nutritients into your life if you’re trying to lose weight (like darker greens and lean meats). It’s more fun and way more sustainable in the long run.

Hmm, this fad dates back to the 1930s and claims grapefruit has fat-burning properties. So all you have to do is eat one before every meal, and bam, your fat just melts away. But doctors, including the folks at WebMD, are skeptical. Grapefruit is a healthy option for breakfast, but it’s not going to magically make you lose a dress size. Sorry.

If you’re a sweets fiend, swapping out two meals a day with prepackaged protein "cookies" might sound like a dream. (We're not endorsing them, but you can buy 'em here.) But this diet recommends eating only about 1,000 calories a day, which is about half of what doctors say you really should be eating. Experts interviewed by The New York Times say it’s not worth the risk.

If your morning green juice is the highlight of your day, you might be tempted to try this diet, which involves drinking almost exclusively vegetable juice, broth and herbal tea for 21 days straight. But beware of these types of extreme cleanses—you’ll probably lose fluid weight, but as soon as you start eating normal foods again, you’re likely to gain it all back, David T. Derrer, MD of WebMD warns.