How do i lose weight if i have copd and can't exercise?

Start slow: You don't need to run to lose weight. Even walking will help you lose weight. In the beginning, walk for very short distance, take break and then walk again and slowly it will improve. Also, optimize the COPD with medications and smoking cessation.

Diet....: If you can't exercise, then you are left with diet alone. But, you may be able to exercise in spite of copd. Ask your doctor about pulmonary rehab, a program where you exercise while being closely monitored. You can be evaluated so you know if you need supplemental oxygen to exercise as well as what exercise you can do safely. If you smoke, quit today! good luck!

Try light exercise: Even mild exercise like walking will help you expend some calories and lose weight. That being said, with the inability to perform more intense exercise, your diet becomes more important.