Onions and celery do have nutritional value. Onions are a source of vitamin C, B6, Folate, and potassium. Celery brings Vitamin K, A, C, and Folate though to be honest, there isn’t a ton of vitamin C in celery and there is quite a bit of sodium. Foods that offer little to no nutritional value are things like chips, pretzels, soda pop, candy, and things made with white flour.