If you're serious about changing your derelict diet—and losing a few pounds along the way—a resolution can help. A study published in the Journal of Clinical Psychology reports that those who pledge to make behavior changes by means of a resolution were 10 times more likely to succeed than those who simply want to make a change. Going public and sharing your goal with someone can also bump up your odds for success.

But a commitment to better eating is only the start. You also need to figure out how and what to change. Here are four suggestions that can put you on the right path:

1. Keep a food record

To fix your diet you should understand where it's broken. One good way to do that, says Washington, D.C.-based registered dietician Katherine Tallmadge, is to keep a pencil and notebook handy as you go about your day. For at least a week, record everything you eat, when you eat, and maybe how you feel after you eat.

The exercise can be eye-opening, says Tallmadge, who is also author of "Diet Simple: 214 Mental Tricks, Substitutions, Habits & Inspiration" (LifeLine Press, 2004). By analyzing your eating routines, she says, you can discover both the good habits you practice as well as those that regularly route high-calorie, low-nutrition fodder toward your mouth.

It can also unveil such misguided behaviors as chronically skipping breakfast. "Studies have shown that if you eat breakfast," Tallmadge says, "you eat proportionally fewer calories the rest of the day."

Keeping an ongoing food record while trying to establish better eating patterns can make you accountable to yourself and discourage mindless eating.

And make sure to record one other item: your weight. Climb on the scale at least once a week if not every day, says Tallmadge.