If you are referring to a Diabetes Education Class, taught by a CDE (Certified Diabetes Educator), I suggest you attend the class, along with doing your own research. CDE's education (as with MD's education) is funded by drug companies that manufacture diabetes drugs; that's why you'll see lots of drug ads in their literature. I also saw information about "Healthy food choices at McDonalds, Burger King, & KFC." Money talks....especially ad money.
At my diagnosis 12 years ago, I attended several classes. 80% of the time was spent telling us which drugs to ask our doctors for, the rest of the time was showing us rubber molds of what a serving of pasta or rice looks like. Well, since those are starchy processed foods & very high in carbs, I rarely eat those. (100% of carbohydrates are converted to sugar). A small serving of rice or pasta has 40 gms of carbs - same as a can of Pepsi, & very little fiber. That's OK - if you're going to play basketball for an hour or two.
Healthy eating for diabetes isn't much different than healthy eating for non diabetics. 80% of our diet should consist of raw fruits & vegetables, the rest should consist of protein & legumes (beans). Beans are the highest-fiber food on the planet - something diabetics should keep in mind. Fiber is important because it slows down the digestive process, which prevents blood sugar spikes. Fiber is only found in plant-based foods. Meat & dairy have no fiber. I limit (not eliminate) other "fun" foods - anything made with flour, potatoes, grains (like corn), bread, desserts. Processed foods like chips, bread, pasta, etc. will spike blood sugar in most diabetics. If you like meat, it has no carbs (unless it's breaded), so it's OK, but it is high in saturated fat, which may or may not be good for us, so I limit that as well.
Many diabetics totally eliminate sugar & prefer artificial sweeteners. I don't; I think they are much more harmful than sugar. They are on shelves because people want them, thinking they are better. The key word here is "amount." I use 1/2 tsp sugar in my coffee. How much sugar is in sugar? One tsp (one of those restaurant packets) has only 4 gms of sugar. Compare that sugar content to a medium-sized apple or orange - 15 gms sugar.
However, a can of soft drink has 40 gms of sugar - that's 10 teaspoons. And who drinks only one can? Before my diagnosis, on a hot summer day, I'd have at least 4 cans. Yeah...160 gms sugar - not counting any food. That's where excess sugar comes from - along with favorites like cookies, ice cream, etc.