Surprisingly, not much. Despite their popularity, only a handful of studies have been published on the effect of detox diets and cleanses (usually juice) on weight loss. As expected, the results suggest that detox cleanses may work on the very short-term, but once people get back to any resemblance of a normal diet, the weight comes back. Now, for those of you thinking of going on one of these cleanses to temporarily lose weight for a holiday photo op (okay, in 2022 we all know it really means a selfie) or to make extra room for the actual holiday meal, you may want to consider a few things.

The NIH has a nice summary on their take when it comes to detox diets and cleanses, and they call out several safety items, including:

1) The FDA and FTC have taken action against some companies selling detox diets and/or cleanses because of false claims and in some cases, for containing illegal and potentially harmful ingredients;

2) Detox diets and cleanses are severely low in calories and total nutrients, so they’re not sustainable because they can quickly lead to nutrient deficiencies (it only takes a few days to weeks);

3) Drinking very large quantities of water or teas and/or not eating foods for days can seriously alter your electrolyte balances which is flat out dangerous and life-threatening;

4) Oxalate. Funny thing about oxalate: it’s found in the really, really “good for you foods,” like spinach and beets, but when you highly concentrate it (e.g. by making a concentrated spinach and beet juice), you can quickly take in more than what your kidneys would like to handle. Now, for people with properly working kidneys, it may not be a big issue, although those kidneys may be working overtime. But, for those with certain underlying (and often unseen) medical issues, it can cause significant kidney damage. So, yeah, I guess there is a such thing as too much spinach.

The bottom line is that there is no magic bullet to lose actual fat weight quickly or “cleanse” your body. Like all good things, it takes hard work and time to earn them. In this case, it means committing to nourishing your body with vibrantly-colored, nutrient-rich foods every (or most) days, portion control and drinking good old-fashioned water. If you’re interested in reading more about the research on detox diets, here’s a 2015 critical review.