The parents are invited to celebrate the birthday with the child, and I don't think anyone missed sweets at all. In fact, it was a lovely celebration of M's life. The children all sit on the floor while the birthday child walks around a candle once for each year of her life. The parents are invited to share a special story about that year and the children sing a lovely song. It was all very special and more of a celebration than a tray of quickly consumed cupcakes might have been. M had cupcakes at her party and cake for the family celebration in case any of you worry that she is being deprived! :)
We incorporate sweets and treats in our menu planning, and I guess I am thankful that the school doesn't have a constant parade at all hours of sweet treats. I know that their snacks offer protein, fat and carb and I get to pack her lunch. (We offer sweets during certain snack or meal times with a protein if possible like a glass of milk so it lasts longer and doesn't spoil her appetite.)
You might find out what your school or childcare does. I would worry if the policy on food is too strict. If the school tries to limit portions of foods (in the name of health or "obesity prevention") or serves snacks with only carbs (graham crackers and juice or water) with no fat or protein, I would be concerned. Also ask that the adults feeding your children don't enforce "growing food" before dessert rules, or make kids feel bad about the foods they eat. The adult's job should be to provide a pleasant atmosphere, limit distractions, help the children set out the food, and if possible model enjoying a variety of foods. They also need to adhere to the division of responsibility and not push your child to eat more or less than he wants to. (See https://ellynsatter.com/resources.jsp and scroll down to resources under child care policy where you can download a PDF and bring it to your school or daycare if you have concerns...)
per request, another post about rituals with kids...