It's not that simple, sadly, if it was my job would be way easier. Yes, your cells (usually) run on glucose but that glucose can be produced from a variety of dietary sources including sugar (sucrose, fructose, etc), other carbohydrates, and fats.
Reduced dietary sugar (particularly the added sugars) is an amazing public health outcome.
That argument relies on the assumption that we only eat/consume if we need energy. Thank you you have just solved obesity, because nobody eats more than the energy they need!