Oftentimes, quick weight loss goes hand in hand with crash dieting, but this isn't always the best solution. “Crash diets” are typically extremely low-calorie diets that require drastic measures - like eliminating multiple food groups, drinking only juice or soup for weeks, or fasting for multiple days to cut out as many calories as possible.
Very low-calorie diets (VLCDs) are also used as treatment against obesity in some medical centers, but these programs are supervised by trained physicians, and are not necessarily the right approach for everyone (48).
But starving yourself only works for a little while. And even if you are successful in sticking to an extreme diet, you may end up gaining it all back once you go off it. T
his is mainly because short-term diets can promote a lot of water loss (not just fat loss). In addition, depending on how long these diets persist, they can do a number on your hunger-regulating hormones, mental state, and potentially your metabolism. Crash diets can also be dangerous for certain individuals.