I believe that your answer lies with each individual person as to their biggest obstacle and how to overcome it. However, I can offer some ideas which fit your question. One of the major obstacles is mental--the belief in your ability to conquer the reluctance to become an active person. A major way to overcome that obstacle is to find a health coach which many insurance companies offer for free, or to find a partner who will support and accompany you in the exercise you need. Another major obstacle I see is major health problems which interfere with exercise such as fibromyalgia, surgically repaired or replaced knees or ankles, or excessive weight gain which occurred gradually with each surgery. A way to overcome this obstacle is to start slowly with a supportive doctor and physical therapist who can find minimally jarring exercise or prescribe a pool program to remove the physical discomfort of weight on unstable or compromised joints. The economic obstacle which has the poor on fattening foods as filler and the poor health care because of the money needed requires that the health care system change to help the economic poor who cannot eat a healthy diet as it is more expensive to eat healthily. The change needs to start with small children which the school systems in many states are starting to understand and have begun serving far more nutritious foods with fewer calories or fat and are beginning to see results.