Eskie,
Why do you assume the friend wants an exercise buddy? Maybe they already have an exercise routine. Maybe they have tried numerous programs with no success. True, health care providers are concerned about the obesity epidemic in the US but many practitioners are stressing that the person's size is not important as long as they live a healthy lifestyle and are healthy. Sadly, as we learn more about metabolism, hunger, internal eating controls and individual physiology we are also learning that weight loss is not reasonably achievable for all some people. Infact, putiing people on strict diets causes more problems than it solves. A diet does not solve anything but can result in depression, eating disorders, slowed down metabolism, distorted thoughts about food and many more negative factors that interfere with someone being able to develop a healthy relationship with food and exercise.

Just because someone is overweight does not mean they want help from anyone. I'm sure they have received more than enough unwanted help from many, many sources and really just want to be left alone and allowed to live a happy life without constantly worrying about their weight.