Perhaps outside the scope of my pharmacist blog, but I will tackle this question since I maintain board certification in nutrition support:

Honestly, I am not familiar with this strategy. I did a quick search on “cleansing” diets, and I have to say they appear to be nothing short of ridiculous. Also, a pubmed search of the terms “colon cleanse”, “cleansing diets”, “detox diet”, etc. turns up only information pertaining to evacuating the colon prior to colonoscopy. None of the websites I browsed that promote the diets cite any reliable scientific evidence of safety or benefit. 

It would not be healthy at all if sustained for any significant period. The body needs protein to avoid catabolism, and sufficient protein intake is unlikely to occur from a diet restricted to fruits and vegetables. Additionally, the body needs certain fatty acids to sustain life. Once again, unless a significant quantity of avacados were consumed, this is not likely to occur from that type of diet. 

A healthy diet will contain a various foods choices from all of the food groups. Studies have suggested that diets plentiful in fruits and vegetables may reduce the risk for certain cancers and cardiovascular disease, so they are an extremely important component of a healthy diet. But eliminating all other food groups is not a good idea. 

I think it is safe to state that there is no evidence to support any health benefit or sustained weight loss from the use of a cleansing diet. Looks to me like another case of some clowns trying to make money utilizing a “snake oil” approach to promoting health. 

Hope this helps!

Aaron Emmel, Pharm.D., BCNSP, BCPS