Blueberry muffins may contain healthy fruit, but the high sugar content makes these baked treats quite unfriendly if you're watching your weight. On average, a medium blueberry muffin contains about 426 calories. Particularly troubling, 148 of those calories come from sugar. According to American Heart Association guidelines, most women should get no more than 100 calories per day from added sugars, while most men should limit added sugars to 150 calories per day.
Calories by Size
If you can't resist the lure of blueberry muffins, settle for a mini version to spare your waistline. These muffins are about 1.25 inches in diameter, and have just 64 calories each. Small, 2.75-inch muffins are also a smarter choice at 249 calories each. Stay far away from large muffins of 3.25 inches, as they have about 524 calories each. An extra-large muffin will get you even deeper in diet trouble -- each contains a whopping 633 calories.