I watched a retro presentation on cancer recently. One of the statements made was that to date, all successfully cured chronic metabolic diseases have found their remedy in something related to diet (generally speaking, what you should consume but don't, or what you are consuming which you shouldn't).

I am not talking about chronic metabolic diseases that do not yet have an outright cure (i.e. cures not treatments). I am referring only to those diseases which have a definitive accepted remedy (such as scurvy etc).

I am not a medical doctor obviously, and I would be interested to find out if the statement about being related to diet is in fact true.