Is there a fast way to lose 40 pounds i'm asthmatic and is hard to go on diets?can exercise and dieting be the only solution?

No fast way: There is no healthy or safe way to lose 40 lbs fast. With a proper, well-balanced diet, limiting fatty & processed foods, sweets/"junk food" and soda, and with moderate exercise (especially cardiovascular exercise - walking, running, elliptical, swimming), you will lose weight and get healthier at the same time. This will also potentially help improve your asthma.