The diabetic diet I followed (and still mostly follow) is 2 or 3 “carb units” per meal, 3 times a day. Each carb unit is 15g of carbs. Start looking at labels. If you balance it out with reasonable portions of protein you can lose weight. I’ll warn you in advance it requires some willpower. It’s all about portion control, mostly. If you want a snack later, you have to save a carb from one of your meals. In other words, you can have 2 carbs at dinner and have your third carb for a snack later. Ate 3 carbs at dinner? You’re screwed. No snack for you.
A slice of bread is one carb unit. Fruits and veggies aren’t necessarily your friend. They often contain sugar and have to be counted as a carb unit. A potato is two or three carb units depending on how big it is. A scoop of rice (enough for a side dish) is one carb unit.
There are a lot of 100 calorie snack packs. They aren’t like eating real snacks. Sure you get a bunch of cookies, but they are all miniature teeny tiny cookies. But that’s all you can have.
It sounds like your doctor didn’t explain diabetes very well to you. Your cells have insulin receptors on them, which is how the body regulates your blood sugar. If there is too much sugar, then your body produces more insulin. This is produced in special cells in your pancreas. If you eat a lot of sugary foods, the cells have to work harder, which strains them, and after years of abuse they will start to die off. The thing about these cells is that they don’t regrow. If you kill them, they are gone forever.
Being overweight clogs up the insulin receptors in your cells with fat, which means that the body has to produce more insulin to regulate your sugar, further straining those cells in your pancreas. If you lose weight, then you’ll get rid of the fat that’s blocking the insulin receptors, and even though you may have already damaged your pancreas a bit, it may be able to produce enough insulin to regulate everything properly. So you can kinda “cure” your diabetes by losing weight, sometimes. It’s not really a cure, though. It’s more that you have managed your diabetes to the point where you don’t need medicine and don’t need to worry about it. The damage to your pancreas is permanent and still there.
So losing weight is very important.
You are probably at the beginning stages of type II diabetes, which means that if you lose weight and watch what you eat, there’s a good chance you haven’t done too much damage to your pancreas and you won’t need meds or anything later.
If you don’t lose weight and don’t watch what you eat, you’ll do even more damage to your pancreas and then you’ll end up on meds for the rest of your life.
Count carbs and don’t go excessive on other foods to make up for it, and you can lose weight. Don’t worry so much about fat content of nuts and stuff like that. Focus on the carbs. You don’t have to be anal about getting the exact total grams right. If you round to the nearest carb unit that’s usually good enough. Eat well rounded meals with the right carb amounts and you’ll be fine.
ETA:
One other thing. Keep moving. That helps burn off calories and reduces your blood sugar which means your pancreas doesn’t have to work as hard. Walk a lot. You don’t need to start jogging or go extreme on the exercise. Just walk around a lot. Move around a lot while you are sitting at your desk. It all helps.