The worst fad diets for your brain and body, from the Bible-inspired Daniel Fast to the werewolf diet

Fad diets are popular ways to lose weight, but they don't all have science on their side.

Yo-yo dieting can be dangerous and set people up for long-term heart trouble.

Nutritionists agree it's best to stick with a diet plan that you can adhere to for life, instead of zig-zagging in and out of restrictive plans that set people up for failure.

Fad diets are nothing new. The first modern fad diet, which touted the benefits of going low-carb, was invented by funeral director William Banting in 1862. Since then, the world has seen its fair share of dieting trends, from eating cabbage soup for a week straight to consuming foods based on your blood type.

Despite the ridiculousness of these fads, and lack of research supporting many them, fad diets continue to play a role in how people eat and attempt to take control of their health, for better or for worse.

Here are the fad diets that can be worst for your brain and body.