This has nothing to do with modern diet, the trend the GP is speaking is at least centuries old.<p>Traditional Chinese culture believes raw food damages the Qi of the Stomach. This belief may be grounded in the fact that their traditional way of fertilizing the crops is &quot;night soil&quot; or human excrement. Eating raw vegetables is a maladaptive behavior under those conditions.<p>It might be also linked with cooked foods being easier to digest. China has had  high population densities - and therefore a recurrent problem with crop failure leading to famines - for many centuries (at least in the river valleys), so using non-eatable plants as an energy source to make human digestion more efficient is also an adaptive behavior.