Is it better to lose weight by aerobic exercise or spinning?

Spinning is the most active exercise in the gym, which has a good effect of losing weight and burning fat, and aerobic effect is also good ~ I think there is no conflict between the two. You can make a plan according to your own interests, such as what classes to take on the week and what classes to take on the week ~

Under the condition of ensuring the intensity of exercise, we must eat reasonably and pay attention to the nutrition collocation, so that the effect will be good.

I suggest you talk to the fitness instructor in the gym and ask their opinions. They have a more intuitive understanding of you and may give you more suitable advice.