Every year, millions of people “resolve” to lose weight. It’s the number one goal set each January 1. And by about this time each year, it’s the most abandoned one. There are dozens of theories about why that might be, but the explanation I like most (because we can do something about it) is that our optimism tends to overpower any thought of contingency planning.

It’s true of any goal, really, and makes some sense. Thinking about why something might go wrong, and how to deal with it, is a bit of a downer. But the plain fact is that in any situation requiring a change, such as chasing a goal, there are strong forces at play and obstacles in the way.

Nearly 70 years ago, social psychology pioneer Kurt Lewin called the forces working in your favor “driving forces,” and those working against you “restraining forces.” I’m a cyclist, so I like to think of these winds of change as tailwinds and headwinds.

According to Lewin, driving forces help you achieve the desired change and are generally positive, reasonable, logical, conscious, or economic. (For example, looking better, fitting in clothes, feeling better, higher self-confidence, and better health.) Restraining forces are generally negative, emotional, illogical, unconscious, social or psychological. (For example, willpower, discipline, motivation, rationalizing, etc.)

Here’s the thing: restraining forces rule. If you don’t acknowledge, evaluate, and plan for them, the chances of you succeeding are significantly decreased. In other words, if you love a good midnight nosh, you better have a rock-solid plan in place for when the refrigerator calls your name, or dropping that ten pounds so you can look good in your letterman sweater for the class reunion is a distant pipedream.

Lewin came up with a simple tool he called Force Field Analysis to describe a current situation as a state of equilibrium between driving and restraining forces. You can use the analysis to map the forces and do some planning. There are six steps involved:

1. Start with a well-defined goal or change to be implemented.
2. In the middle of a sheet of paper, write the goal or change to be implemented.
3. Title the bottom half “Driving Forces.” Title the top half “Restraining Forces.”
4. Brainstorm a list of driving and restraining forces and place them in the appropriate space.
5. Once the driving and restraining forces have been identified, ask and answer the following questions.
   • How significant is each force?
   • Which forces, if altered, would produce rapid change?
   • What skills and/or information is needed to manage the forces?
6. Create a responsive course of action that follows one of three strategies:
   • Strengthens driving forces
   • Weakens restraining forces
   • Creates new driving forces

When I work with creative teams and new ideas, we always perform a Force Field Analysis before we pitch the idea. The reason is pretty simple: pushback, yeh-buts, and objections always come from the restraining forces side of the page.

We’re always ready for the resistance this way. We never have to do a dance for an answer, because we can easily point to the counterbalancing driving force.

Matthew E. May is the author of In Pursuit of Elegance: Why the Best Ideas Have Something Missing. He blogs here. You can follow him on Twitter here.