Most important thing is to count the number of calories you eat. A 12oz can of pepsi actually has 150 calories. So your 40 minute commute probably burns off the equivalent of two 12oz cans of soda. Losing 40lbs at a rate of 2 lbs a week means it will take a minimum of 4.5 months of maintaining a 1000 calorie (~6 pack of soda or 2 hours of 11MPH cycling) deficit every day.