You could very well be reacting to the oats.
Eat more meat. Eat larger portions of meat. Cook up a large pot of it on the weekends and pull out a serving when you need it.
Boil eggs so you have them available when you need a snack.
Try eating starchy vegetables and fat to see what works for you.
If you want to "burn fat", you need to accept that the only time you truly burn fat is when you are hungry. Your body runs out of food and starts recycling your fat reserves. Extra points for exercising fasted. Have you tried IF? Check out Intermittent fasting diet for fat loss, muscle gain and health. It's for people who want to lose fat while gaining muscle mass.