Bicycle belongs to aerobic exercise most of the time. Except for sprinting and climbing, the heart rate can reach the limit value of people in both cases, which belongs to the anaerobic range.

However, losing weight is inefficient. I rode 100km on New Year's Day, using garmin's heart rate belt, and the heat measured by the meter was about 1700 calories. It took 3 hours and 40 minutes, and I ran half a horse 1 hour for 50 minutes, consuming 1400. It took twice as long and only consumed 300 calories. The reason is that when riding a bicycle, you don't need to do work by your own weight most of the time except climbing the hill, but you have to do work by your own weight at every step of running.

Of course, if you can ride 100km in two hours, it will be more efficient than running, but I don't think amateurs can ride 50km without traffic control. If so, the professional marathon runner 2 1k is actually in the early hours of the morning.