well I am not a mother, and not quite a child either. I am just turned 20, and even though no one really restrickted my eating habits when I grew up, I never had much of a selection. between my grandparents and my mother, I was exposed to eating healthy meals and never candy. dessert and sweet things were traditional, since my family is european. but also my parents were not as well off when I was a child as in the present. so when we went to the grocery store, I was allowed to chose 1 thing I wanted in the snack items. I could never get ceral with the toy insdie because I wanted it. or bags of candy. I learnt without any feeling of oppresion that while I had plenty to eat of what was good and healthy, I had no reason to be hungy for candy and sweets. I often turned them down when offered to me because I never had the taste for them.
So, I think it is really a good idea for parents with particulatly young children to not indulge a child's every whim even if they financially can do so. While it is better to have plenty than to lack, there is a diiference between enforcing values that teach 'I should not be over-indulgent.' Over-indulgence to me is the same as drunkeness, like a bad habit, like an addiction.
So no I do not think it is selfish to protect a child's health. If you start when your children are young, they won't feel a sense of depravity. Teach them yourself that those things are bad for them, and that certain food are good for them. Then they can make their own decisons and it won't be as if you are hiding sugar and doritos from them. They will know it's there and it's not a good thing.