Raw food or cooked?   Both are good and both have their place. Yes, a raw vegan diet will cleanse the body and reset many things (like a health reboot).  But sustaining a totally raw diet for a long time is difficult and, I would venture to say, not necessarily healthy for everyone. Chinese medicine explains that the digestive system is like a burner on the stove to cook the food. If the heat is adequate the food will cook properly. The digestive system works better with warm or hot food. Raw or cold foods put out the burner and tend to slow down or affect good digestion.  That is why people who eat a lot of raw or cold foods may experience diarrhea, loose stools, and difficulty digesting certain foods.

In very hot weather the body can tolerate and even needs more cooling foods such as some raw salads and fruits.  But in cold weather one should avoid raw foods in general and eat more steamed or baked vegetables, lightly sauteed vegetables , soups and hot foods.

A person can eat a raw food diet to detox. But to sustain such eating a long time is very difficult and I do not believe it is very healthy either.  One would lack protein and other nourishment.  There are places that specialize in raw foods and people go to detox and improve their health by eating only raw salads and sprouted vegetables and fruits etc.  Many people feel great….but that is only initially. After a while they find it too hard to sustain.  And there are some people who feel terrible on raw foods: they develop a lot of gas and digestive issues. 

Steaming or cooking cabbage or kale makes it easier to eat. It breaks down fibers. Some people cannot handle raw high fiber foods like green beans or kale etc.  Don’t force yourself to eat things your body does not feel good with. Stick with foods you can digest well but have high nutrition.
I believe a combination of some raw foods and some cooked is the best diet in the long run. Raw foods obviously maximize vitamins in the food. But if you cannot absorb the vitamins due to difficulty digesting food, is not so beneficial.

People with IBD or IBS often find raw foods damaging to the digestive system.

Every situation is different.