Breathing more / denser oxygen is very bad for you (breathing at all is bad for you). Furthermore, badly treated asthma (i.e. you cannot breathe well) will lead to very fast weight loss.
This should inform you of one thing: anaerobic respiration is inefficient and therefore great for burning more calories. An easy way to achieve such respiration is running or cycling (which I think is better on your knees) so fast that you start panting. Keep doing that for an hour and do it every other day.
This advice is IMO better than "eat less", because changing your dietary habits is very very hard. Moving more is much easier by comparison, though sadly it still won't be fun for you in the beginning.
Patients with severe respiratory difficulties lose weight because of the added effort. They spend more energy trying to breathe, or more precisely "waste"
This should inform you of one thing: anaerobic respiration is inefficient and therefore great for burning more calories. An easy way to achieve such respiration is running or cycling (which I think is better on your knees) so fast that you start panting. Keep doing that for an hour and do it every other day.
This advice is IMO better than "eat less", because changing your dietary habits is very very hard. Moving more is much easier by comparison, though sadly it still won't be fun for you in the beginning.