I guess my nutritarian thinking on this (and I guess that's close to what they call Natural Hygiene) would be that if you aren't getting enough MICROnutriens on the type of food that you are eating (which I guess is quite likely if it's the sort of food that feels addictive), fasting will merely exacerbate the problem, and fasting will be difficult since you will be releasing a lot of toxins.
I think this is why so many people cave in, and then eat the same food, because it's all they know.
Having said that, a long fast CAN re-educate yourself, I found that out for myself (but I was eating reasonably good food before the fast, just way too much of it). By long I mean probably 21 days or so, but I don't think it's a good idea to do a long fast after a prolonged period of the Standard American Diet, as it's called. They didn't have that in Shelton's days, and in any case Shelton's fasts were supervised.
I think the SAFEST and BEST option would be to try a plant based diet BEFORE doing any fasting, you can learn a little bit about it here http://www.plantbasednutrition.org/fileadmin/Promo/index.html
and it has er... just a few little benefits too! They say it takes up to six weeks to adapt, but I guess that depends on the individual.
Having said that, if you are eating plenty of fresh fruit and vegetables now, then a long fast may work, even though it may not necessarily be the best option.
(edit2) I just noticed this is 5 months old, for some reason Curezone made this appear at the top of my page! I guess I was taken to an old page, I notice Curezone has been doing that lately