Desire and motivation, I would suggest, are not the same thing. While a desire is felt initially in the present, it can be put on hold, so to speak, until motivation catches up with and matches desire. Desire is a goal that is felt in the present; motivation is the fuel to reach the goal in the near- or distant future. The gas tank of one's motivation can be full--to the brim, or it can be less than full--all the way down to empty.
In the following paragraphs I'll use as examples the desire to become rich and the desire to achieve a fitness- and/or body-image goal, but these are for illustrative purposes only. A desire may be generic, but the object of desire obviously varies from person to person.
Take the desire to be rich. The very thought of having oodles of money may trigger all kinds of fantasies within you. That does not mean, however, that your desire will trigger the release of motivational fuel. For all the people who entertain--however fleetingly--the notion of being rich, there will always be those who say, "I'm content to fantasize about being rich," and others who determine to be rich and who make it a goal and pursue it.
In fact, determination is a synonym for motivation. They are both fuel, but motivation, I suggest, is "regular," whereas determination is "premium" (or high test).
Louis Tice of the Pacific Institute suggested that motivation is the act of throwing yourself out of order and then achieving order once again. I like that. In other words, the desire comes first, and then motivation. Motivation, in essence, involves saying to ourselves,
"I'm out of order now, but I'll achieve order once again by doing X, Y, and Z."
Some people neither desire nor fantasize about becoming rich. The notion doesn't even enter their minds. More altruistic than some others, they desire no more than to have their basic human needs met (food, drink, clothes and shelter--or maybe just the first two!). As far as wealth is concerned, their gas tanks are bone dry. Their version of being rich is to have satisfying relationships with a spouse, family members, and friends, and to be content in their chosen vocation. For these things, their gas tanks are full, or close to it.
Along with determination, some of the concepts that are almost always in the company of motivation and desire include:
Discipline
Endurance
Habits
Goal-setting
Commitment
Values
As for the desire to become fit and/or achieve a body-image goal, at one extreme are theorists who eschew the concept of motivation as fuel, and embrace discipline instead. As Joseph Brandenburg, a certified fitness instructor and co-author of Results Fitness says,
"Fitness isn't a matter of motivation, but discipline. Motivation is a feeling. Feelings come and go; you just can't count on them. Keystone habits, on the other hand, from something as small as making one's bed every morning to rising every morning at five to run a few miles, can develop discipline and structure in other areas of our lives."
On the other hand, Glen Getz, neuro-psychologist, marathoner, and writer on goal-setting says,
"Somebody could easily argue that you need to have motivation to be disciplined. Research shows motivation to be complex, and to say only discipline matters and motivation does not, is to oversimplify things. . . . Discipline is the personality trait component of motivation."
Admittedly, discipline can be a scary word, and too much discipline can be harmful when it causes us to overdo things, such as exercising too much or starving ourselves to achieve unrealistic goals. Only when there is congruence between our behaviors and our core values will self-discipline and quality of life go hand in hand; hence the importance of identifying what it is you value the most and what behaviors will aid you in achieving that value.
If, for example, being comfortable inside your own skin is a core value, even if according to the latest body-mass-index height-and-weight chart you happen to be overweight, why then should you care what another person's ideal BMI happens to be, assuming it's different from yours?
Finally, commitment can and will be tested once you set (and write down!) a goal. When challenges get in your face, as they inevitably will, for example, when a runner "hits the wall" six miles into her run, your having developed good habits, sensible pacing, and increased levels of endurance--all these will pay off if you simply hang in there.
To slip occasionally is not a disaster, particularly if you've developed the right kind of habits and are doing what you enjoy doing. One person's pain, after all, is another person's pleasure. Running is perfect for some; for others, it's tennis or pilates.
And while a workout buddy or a person with whom we have shared our desire, whatever that desire happens to be, can help keep us accountable, as certified personal trainer Kat Barrett says,
"In the end, you need to be your own best cheerleader."