Ideally you want no spikes, because you are eating a balanced diet and avoiding meals and snacks consisting largely of refined carbs and refined sugars. A proper meal shouldn't really create a blood sugar (and resulting insulin) spike as much as a gradual elevation and fall back to baseline, because protein, fat, and fiber all slow digestion, and complex carbs (and even sugars within fiber/nutrient matrixes ie whole fruits) don't tend to spike blood sugar too badly in the first place.