hi Jenny,
I totally agree with Samcogle here, it's totally about Trial and error and seeing what works and what doesnt.
I follow the low-carb diet like a lot of people on here and i find that works for me.
I can't eat most fruits, bread, pasta, starchy veg and millions of other stuff but i have managed to find some meals that are good for me.
your husband needs to test test test and then test some more. i am still learning about my body so at the moment i am testing like 10+ a day just to see whats going on in there.
I would really recmmend low carb i find i can control things much better and if your husband tried then im sure he would find that the weight would fall off also.
good luck to you both,
x