Doesn’t sound quite right to me, I’ve got 2 children, but then I am not a doctor. Does he have any other indicators like poor concentration, hyper active, raging thirst etc? Does he prefer certain foods to others? I.E. crisps rather than sandwiches, pop to water, chocolate to fruit. Is he active or lethargic? Has he gone through a growth spurt?
Our cat, no I’m not a vet either, has just been diagnosed with a Thyroid condition which can affect appetite.
If your son is otherwise healthy, and his manner hasn’t dramatically changed I’d see if this behaviour peters out over the next couple of weeks, he may be reflecting the increased eating of many people over the past 2 weeks. If there is no change then a visit to your doctor would probably be wise and reassuring.
As easy as it is for me to say try not to get things out of proportion there will probably be a simple, rational explanation.