Exercise equipment that allows weight bearing exercise involving both the arms and legs may be the best choice for obese individuals. Using an elliptical trainer allows you to burn more calories than a stationary bike at the same perceived intensity.
Treadmills (weight bearing, but no arm action) and airdyne cycles (arm action but not weight bearing) produced better results than the stationary bike, but failed to match the elliptical trainer.
Exercise intensity can be measured in many different ways (oxygen uptake, heart rate, perceived, lactate etc.), but for most people perceived intensity provides an easy and reasonably accurate method of establishing the correct intensity.