I would say a 630 calorie donut is pretty huge. After looking at the calorie info for a bunch of Tim Hortons donuts, the average seems to be around 250 calories.
Come on down to the US and you will find 600 calorie donuts aplenty.
Therein lies the rub: most people can't fathom they're eating way too much since they feel like it's normal because habit and social.