We can have no success in our work or business without people hiring us, promoting us, or buying our goods or services. We can have no success in marriage or friendships without the cooperation of others: they hold the cards. People leave. They die, they move on, and sometimes friends just stop calling with no warning or explanation, leaving us to wonder, what happened? There is little in life that really matters for which we do not need the permission or cooperation of other people.
The one wonderful exception is fitness, or lack thereof. It's our choice, and ours alone. We alone decide what and when to eat, how much and how often. We alone decide whether we sit around the house during our off hours doing nothing, or engage in regular physical activity.
We cannot control our relationships, or their outcome: if the other person is finished, then it's over no matter how we feel. If the economy sours, or the boss hates us, we can lose our livelihood, no matter how much we love the job, how desperately we need it, or how good we are at it.
The one and only thing we can control is the appearance and fitness level of our own bodies. How ours looks, functions, performs, how strong we are, how soft or firm, how attractive or not, are all things we decide. Right now, you and I are living in the exact body we have become comfortable with up until this moment. When we are no longer comfortable, or satisfied, we can change our bodies by changing our food intake and activity choices. It's that simple. There is no one to tell us "no".