The govt healthy eating advice is being steadily challenged now. Yes we have more children and adults who are overweight, but it seems that the official advice may actually have to shoulder some of the blame.
There is NO evidence that saturated fats do in fact lead to heart attacks. The official advice was simply based on a study that people with high cholesterol had fewer heart attacks when taking anticholesterol drugs. Not the same thing at all.
It is surely no coincidence that heart attacks began to rise after WW2 when the artificial substances began to be added to food.
And the justification for eating low-fat food is often restricted to the "gram for gram, fat contains more calories than carbohydrates". Like, you'd eat 100g of fat at one meal?
If I fed my dcs with the amount of carbohydrates at each meal as recommended, they would soon be fat, they simply can't eat so much. But they have a healthy diet, with all food groups and are not quite as fussed about sweets as some kids I could name, probably because I've always allowed some in their diets.
At the parties I've held for dcs, it often seems to be the ones whose parent are fully into the health kick (no sweets, crisps, etc, etc) who are the first to dive into the biscuits/cakes/crisps I set out.
So in general I home-cook from scratch as much as I can (freezing as well to save time), using natural stuff with as few additives as possible. However, I do allow "naughty stuff" because I don't want the kids getting food hang-ups.
I make the decision, not the school.