How this calculator works
A doughnut is fried dough with sugar, and its energy comes mostly from carbohydrate and fat. A glazed yeast doughnut is about 250 kcal, while a filled or frosted one can reach 350 kcal. The exercise estimate uses the MET system: one MET is the energy used at rest, about 3.5 mL of oxygen per kilogram per minute. A 70 kg person walking at 3.5 METs burns roughly 4.3 kcal per minute, so a 253 kcal doughnut takes about 59 minutes of walking. These are population averages, not measurements of your metabolism.
Formula
kcal per minute = MET x 3.5 x body weight in kg / 200. minutes = doughnut kcal / kcal per minute. For a 70 kg person walking at 3.5 METs: 3.5 x 3.5 x 70 / 200 = 4.29 kcal per minute.
Worked example
Two Boston cream doughnuts at 350 kcal each provide 700 kcal. A 70 kg person cycling at 7.5 METs burns 7.5 x 3.5 x 70 / 200 = 9.19 kcal per minute, so burning 700 kcal takes 700 / 9.19 = 76.2 minutes. The same energy would take 163 minutes of walking at 3.5 METs.
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Frequently asked questions
How many calories are in a doughnut?
A plain cake doughnut is about 200 kcal, a glazed yeast doughnut about 250 kcal, and a filled or cream-topped doughnut 290 to 350 kcal. Size and topping make a large difference, so check the shop's nutrition information when it is available.
Are MET values accurate for me?
They are averages across people of different fitness, age and body composition, so the real energy cost can differ by 15 per cent or more. The estimate is useful for comparing activities, not for precise calorie accounting.
Does exercise cancel out what I ate?
Exercise uses energy, but framing food as something to earn back can encourage an unhelpful cycle of eating and compensating. The calculator is a comparison tool. For advice about your own diet, speak with a registered dietitian.
Why does body weight appear in the formula?
Moving a larger body costs more energy, so the same activity at the same MET burns more calories for a heavier person. The MET value already accounts for the activity intensity, and weight scales the result.