My respons was that I was absolutely interested in a negotiation. And so we did.
He would like to earn some money, and I accepted, calculating the estimated amount spend on the above products on a weekly basis, and multiplied that with 52. Totally random his request equaled the calculation I had made, and we shook hands.
The year started yesterday, and I have decided to join him. Only exception to the above actually allowed is dark chocolate above 70% cocoa.
Grateful for his suggestion, grateful that our second day has gone well, and that he actually turned down cake at school, and later also cake as well as ice cream at a friends' house after school.
Well done Julius! I'm proud of you. Let's keep the spirit.