It would depend solely on how they were being used in a dish. Onions are an herb and a vegetable, so they could be used in that manner. But most of the time French Fried Onions are used as more of a condiment (e.g. on top of a green bean casserole).
As you may know, there are over a thousand ways to use them, in on, or around just about anything. Onions are a part of a lot of cuisines around the world. Almost universally.
It all depends on how you are using them in your dish.
French fried onions are in the fats food group.
Onions are in the vegetable food group because it is an edible plant used for cooking or eating raw.
Chili peppers belong in the vegetable food group.
Snails, or escargot, belong in the protein food group.
Pasta does not belong to the meat and beans food group. Pasta belongs in the grain food group.
Grains.Grain - bread, rice, pasta and potatoes :)
Vitamins do not belong to a specific food group. Vitamins are found in all food groups.
Grain is not a food group, grains belong to a food group - the "carbohydrates".
Puff pastries belong in the fats, oils and sweets food group.
Fish and poultry belong to proteins.
Tortilla belongs in the grain food group.
Eggs belong in the protein food group along with meat, poultry, fish, beans and nuts.