In my opinion, it all depends on your typical lifestyle and your health condition. Since no one leads exactly the same lifestyle as others, you may already have developed your own lifestyle that makes you feel comfortable. FYI, my grandma was 84 years old. She used to be chubby and has been suffering from acute heart disease for a decade. Her family doctor suggested that a stent should be put into her heart and a change in lifestyle is required. Thanks to the operation and the advice from the doctor, right now everything's back on track and she feels quite satisfied with her life. For now, she's about 130 pounds.So I guess it's just a reference. You may want to figure it out according to your current condition.