He licked all the sugar off the surface, discarded the rest.
Mostly, he likes very very simple carbs, e.g. sugar. Normally, he likes cookies, but this is from a Mexican bakery, and those are less sweet, they tend to save the sugar for fillings/toppings. Otherwise, he likes veggies and meat, not starches like bread or not-very-sweet cookies. Tonight, he picked all the veggies out of his veggie fried rice, and at those, leaving the rice.