It might be ok as a type 1 such as yourself, but for type two there can be a lot of carbs in the syn free foods they encourage filling up on eg rice pasta potatoes which being insulin resistant and generally without insulin to cover those carbs is almost certainly not going to be the best approach. And more insulin can often mean more weight gain.
It’s fundamentally the eatwell plate of low fat and potentially high carb and is about calorie restriction but uses a simpler system of categories food falls into to limit counting. It does encourage more unprocessed, fresh food and cooking for yourself as a positive. It also depends what your starting diet is like how much improvement that would be. It does offer group support if you need that.
If you stick more to the veg and less carbs it can work but being low fat too might leave you hungry unless you raise the protein instead.
Personally I think low carb high fat (carefully monitored for insulin needs) is better and the weight loss section in here or in many other groups and forum works better but each to their own.