Re: "one size fits all" fasting theory does not.
Are you saying the issue is body "type" or hypogycemia?
If it's hypoglycemia... I'm hypoglycemic and have never had problems fasting.
And the body type you're referring to is not something practiced in all natural medicine. It's really more focused in that region (India).
I'm sorry fasting didn't produce the results you had hoped for. Did you have someone, a naturapath perhaps, that could help you through it? Perhaps, they could have identified a problem or detox occuring and better prepared you for it. Fasting is hell for some people at first. Sometimes it's because they're in bad shape, sometimes it all mental... My husband, for instance has a hard time with it and he's not at all the body type description you gave, it's mostly because he eats a terrible diet.
Anyway, I hope you find a health regime that works for you. Take care. :)