Has anyone tried the Rosedale diet?

I did a search but can't find any threads on it. I ordered a book from Amazon for my husband to try. Of course I will have to use it also as I am not making different meals for the two of us.
He recently gained 20 lbs. and that is just not good at all with his having diabetes and high blood pressure. I never noticed the weight as I see him every day. One morning I was up early and saw him trying to get into his pants. I do not think squeezing yourself into a size too small is good for the organs inside. So I bought him a larger belt and pants and told him these are only temporary. I can't see being uncomfortable while you diet. Hopefully he will lose it and I will take in the waist on his new pants so as not to waste them.
From what I read it might work for a diabetic. I hope so, as he has to have a simple diet and one that he will not be hungry, or he will not stick to it.