Fitness is the encompassing idea of how healthy you are. When we think fitness, we think of how in shape your body is. But it goes beyond just eating healthy and exercising. Just as knowledge and intelligence are two different entities, health and fitness are two different entities. Health can be defined as one's physical well being. Fitness can be defined as one's ability to use their body to meet their needs.
Depending on your life style, and desires, fitness creates a broad spectrum of meaning. If you have no desire to run marathons, to do any hard manual labor, or to be able to participate in athletic sports, then your level of fitness is defined by your desire. If you need to be able to position and maneuver your body in a broad range of activities, then your fitness level is defined by your needs.
Fitness requires a certain level of need in order to be pertinent to the person, but there are a lot of interesting things you can learn about your body and it's capability by paying attention to how it changes as you continue to strengthen it. There are also notable mental changes as your body becomes stronger, such as increased focus, energy, and obviously strength. Personally, I'm more interested in how much physical fitness increases mental capability.
Since I started seriously working out, not only have I lost weight and gained more physical capability, I have also gained an increased mental acuity, focus, and energy. I am more capable of solving complex problems, as well as increased lateral thinking. These traits aren't necessarily exclusive to my new found desire to be physically healthy, they are simply amplified by my increased mental capability due to physical health increasing.
I also gain some social benefits as well. I'm more confident in my movement, and even my person. I'm still a rather large fellow, but I'm more comfortable with the skin I'm in. This is what most people seek when working out, which I think does a disservice to the rest of what you are capable of gaining from being physically healthy. So to all of you out there who may be struggling to find a reason to work out, or to push yourself to get to the gym, don't look at the number on the scale. Don't look at how your waistline changes. Look for how much better you feel, and how much more capable you are.
Make it important to be able to function on a greater level, to be able to think clearer, and to be able to act in the way you think you should be able to in each situation. Don't let the standard of cosmetics deter you from accomplishing fitness in your life!