My biggest problem is eating something that makes me feel full, tastes good, can be prepared easily (or at least cookable and storable in bulk) and that does not turn into fat.
For satiety you need fiber and protein. All energy above your caloric needs turn into fat, regardless of what food source it comes from.
Beans, lentils and whole grains have plenty of both protein and fiber. Meat and fish has plenty of protein. Fruits and other veggies have plenty of fiber.
Personally I track my food to stay at a reasonable amount of calorie, ensure I have enough protein an fiber (I aim at 1.6g per kg of mass and above 50g per day respectively) and try to reach recommendations for vitamins and minerals, pick a guide for those, they're all more or less the same, most tracker apps use the US FDA one.
It's really important to ramp up the amount of fiber, sudden increase will lead to bad news.
Very open to suggestions here