I've been using a calorie counter app for the past 3 years called Lose It, www.loseit.com -- and it's helped me lose 30 lbs. When you start the program, you enter in all of your relevant stats (age, weight, height, gender, etc.) and pick a goal -- that is a target weight you want to reach and rate (eg, 1 lb/week). I tracked my calories from food and exercise religiously, weighed myself every day, and lost 30 lbs at almost exactly the target rate I chose, which was 1 lb/week. I have successfully maintained that weight for 2-1/2 years now.

As you lose weight, the program automatically adjusts your calorie budget because you need fewer calories as your weight declines. This is sort of frustrating, but if you really reduce your food intake (which you need to do to lose weight), then you gradually get used to eating less. You start reducing portion sizes, cut out unnecessary snacks, and eat healthier food.

Anyway, LoseIt says that I burn about 725 calories per hour cycling at 14-16 mph and 890 calories per hour cycling at 16-19 mph at my age and weight. So, according to LoseIt, I burn between 1500-1700 calories from a typical day's commute that averages about 31 miles over 2 hours. Their numbers are probably on the high side because I generally stay under my budget by about 3500 calories a week, which would mean that I should be losing about 1 lb/week, but I have been maintaining the same weight (with normal fluctuations) for past 2.5 years. However, I followed the same budget when I initially started the program and lost 30 lbs in the process.