Ladies!
A a risk of being jumped on by someone, I can recommend a LOW carb eating plan for weight loss combined with reduced calories too.
For me, who am weight loss resistant, that means virtually No visible carbs. and very little food at all. I also go to the gym and walk a LOT. Keeping a diary helps.
It's HARD to begin with, but eventually one gets used to it.
Essentially, most of us eat too much for a modern mechanised lifestyle. As Stephen Fry said in one of his American programmes, Hamburgers and Frankfurters became the most popular foods in the USA, because they were eaten by people who were working physically hard all the daylight hours.
My T1 husband has gained masses of weight since his BGs have been under better control. As I see it, the answer is to cut the food back, especially the carbs and cut the insulin to match. Needs a lot of testing.AND motivation.
I can see why so many teenagers skip their insulin, to keep thin. ( THEY DO so at considerable risk to their health, but then teenagers are immortal 8)