It depends on your personal understanding of "fit." For some people, that means that you have a beautiful, curvy and muscular body. For others, it means being thin. Beauty standards are flexible [The definition of beauty varies from person to person]. But when talking about being healthy, there are many possibilities for being the right kind of fit. First off all, you must eat from all the food families. This includes oil-seeds, fibers, protein, carbohydrate. The purpose of this is to make your body work well with all the vitamins and minerals and to encourage healthy hormone function. Food is medicine. Besides this, obvious things like : don't stay in bed all day long. --- "Musculous" is a very old word. We very seldom use it nowadays. Better to use the modern word : muscular. 2nd sentence you said : "For some people ... ." Hence you cannot say "For another... ." You have to change it to "For others/For other people ..." Also, some sentences are a little too long. It is clearer when you shorten them.