Diabetic folks

I think, and it sounds like a change in food intake, understand it is not a "diet" it is a permanent change in lifestyle for both of you. You both must agree to do this together otherwise one will perpetuate the other not to.
One or two meals a day is a terrible diet. It kills your metabolism and puts your body in starvation mode, you will likely not lose weight and even more it will make you tired, lethargic, moody etc... The pills she takes to control her diabetes could also play into her mood and mind. It does to me memory loss a little lower than I used to be. Stress as mentioned can elevate BGL.

You will find eating every 3 hours will kick your motab into overdrive and the pounds will drop. A side effect to this is that you will be eating more than you ever did before. Once the positive effects of doing this starts to show it is easy to buy in on it. exercise, start slow, go to the high school and simply walk around the track 2 - 3 or more times a day or a few days a week. It is no stress time together if nothing else. Work up to a brisk walk (maybe weeks later) your trying to get your heart rate up. You need to change the habits and doing so takes time and both of you being accountable for yourselves if not each other.

I use splenda (not the best choice) but it is a compromise I can live with. It takes only a little to sweeten, coffee etc. I haven't used real sugar in years....
I don't use salt either sodium is something very saturated in our food already. I mix Crystal lite in a 2 ltr jug instead of processed juices. it feeds my sweet tooth.