Denyce: I must say your reports are the first honestly negative ones I have heard about this food.

And no not every food will work or have the same results for everyone. It is a wonderful food going by the ingredients alone, it is one of the best. I know a lot of people who will swear by this food.
Really, the only negative thing I have heard about it was problems with gas in some dogs (including a dog i used to have)man that poor thing would fart! lol

About the lite diets, you need to be VERY careful when feeding those and research them. Often lite diets will have more fiber and a lot less protien, which is the opposite of what needs to happen, fiber if carbohydrates, that is what you want to get rid of, look for a diet that has 3% or less of fiber (most light diets have 5% and up!) And also a lot of the meat is removed and replaced with things like corn or grains, which doesn't provide for much nutrition. So yes be very careful whenever you switch diets like that.
I know the so called Science Diet light formula has like 6 or 7% fiber in it, so it's no wonder why people ask me all the time "how come my cat isn't loosing weight on this food!" lol