The corn on the cobb will definitely raise your blood sugar. The tomatoes and onions are kind of in between. Not bad as long as the portion size is not excessive. Carrots are starchy but in limited quantities ok. The other stuff will not affect blood sugar to any degree so can eat all of it a person wants.

It depends on your metabolic health if that is a problem or not. Some people handle it just fine if metabolically healthy. I eat modest amounts of tomatoes and onions but avoid corn and other grains like beans. But that is because if I don't my diabetes will come back. I have to kind of keep within limits or I would need to go back onto diabetes medication and eventually insulin shots again. I don't want that.

Many people would do great on 100 grams of carbs total a day. If you follow the government food guidelines it will be more like 300 grams carbs. If a person adds in a bunch of soda pop or other sweets it could easily be over 400 grams a day. Me being former diabetic I try to keep my total carbohydrate count to under 20 grams, which is pretty limited. But I have become used to eating that way and it just seems normal to me. Plus it keeps me healthy.

100-120 grams a day total carbohydrates gives a person quite a bit of flexibility on what to eat. That can be done by just cutting out starchy vegetables, high sugar fruit and juices and all grains. Going to 20 grams a day maximum requires a person to focus mostly on green vegetables, meat and eggs for their sustenance.