In what’s become an annual post about post-holiday New Year “detoxes” and “cleanses,” Dr. David Juurlink offered an explanation of how they work. “They don’t,” the Toronto medical toxicologist wrote on X.

Despite their enduring popularity, very little scientific evidence exists to support “detox” diets for toxin elimination, according to published reviews, and while juice fasts or water diets can help people shed weight in the short term due to severe calorie restriction, they can also trigger binge eating and rebound weight gain once a person resumes eating normally.