about the same number of calories, (224 calories in a donut, 207 in a bagel) but those calories come from sugar and fat in the donut (4 times the sugar and 12 times the amount of fat).

Sources:

http://www.wolframalpha.com/input/?i=calories+in+a+donut http://www.wolframalpha.com/input/?i=calories+in+a+bagel