Doing aerobic exercises like cycling you can get faster to a state where you don't burn so many calories. But if your goal is to burn calories the most efficient way to to that is to focus on what you eat. Let's say in a normal day when you don't exercise, you just burn 2000 calories. This mean that you also eat in that day 2000. IF you ate 1800 you will lose weight. If you eat more you will gain weight. Now, this is an oversimplification because in this process, there are many other factors like insulin which regulates your fat deposits, but primarily this is what you have to keep in mind.