While we know where science stands on crash diets , what about juice cleanses , those all-liquid, three- to 10-day-long crusades against your body's better instincts? Unfortunately (or, for some, maybe luckily), a new video from SciShow debunks essentially all major claims made by cleanse programs. All that time spent bragging to your coworkers about the wonders of cleansing, all that money you spent on fancy juices, and the effort you put into tolerating those ridiculous flavor names , were all for naught.Most cleanse programs promise to clear out your digestive system, "detoxify" your whole body, and prompt weight loss. In short, none of them make good on any of these, and, if they do, it's only selectively so and temporary, to boot.As far as clearing out and detoxifying go, your body does these things constantly, via the organs that you already have. The only way you'd need to seek outside help would be if your liver, kidneys, or intestines underwent some kind of failure, and, in that case, it'd take more than juice to fix your problem. These claims simply ignore the fact that your body is capable of these functions on its own.Finally, the only weight you lose on a cleanse is the result of your body using up its stored sugar reserves because you're consuming way fewer calories than normal — usually around 1,200, actually, which is crazy-low. Once you return to your normal eating habits, you'll gain that weight back.To be clear, juice cleanses generally aren't dangerous to regularly healthy people — they just aren't as beneficial as they may seem. Check out the full video below, and consider giving the superior and highly scientific taco cleanse a try instead.