You want to lose weight, but you can’t pass by the pastries and pastelitos that pop up at every desk, every cubicle, every dining room table at this time of the year.

Before you go all the way, however, consider this. Research has shown that much of what we do in our lives is ultimately determined by habit. While changing those behaviors may not be a piece of cake so to speak, it may be easier than you think.

In a bestselling new book, The Power of Habit (Random House, $28) , Charles Duhigg explores why we do what we do and how habits form and change.

“What surprised me most was learning that any habit can be changed ... no matter how ingrained,” he said.

Why do some people change for the better while others don’t?

“It’s a matter of diagnosing cues and rewards,” said Duhigg, a reporter for The New York Times.

Researchers have found that cues set off signals to our brains that it’s time for an activity sure to yield a desired reward. In fact, we have learned to associate the cue with that specific reward.

Example: Visiting a friend’s home where food is always part of the visit. That’s a signal to your brain that it’s time to eat (or overeat). Yet the reward is the satisfaction and comfort associated with the visit.

How to change: Replace the food with a walk with your friend. You still get the same rewards of conversation with a friend, minus the guilt and ill effects from the eating. Better still, establishing one healthy habit spills over to other areas of your life, Duhigg said.

Long before this ground-breaking research, Alcoholics Anonymous was helping people to stop drinking by attacking the habits around drinking and the temptation to drink. Replacing the drinking activity with the habit of attending AA meetings and calling other AA members, therapists or healthy friends would yield the desired reward — comfort and a feeling of self worth.

In the case of AA, Duhigg said, “what stuck out is the power of community, and how integral it is to change. Other people are involved in the change. They encourage you.”

Pitfalls to look out for, however, are unexpected cues that trip us up. According to a new study by researchers at the University of Miami School of Business, many people who eat fast food may be reacting to a feeling of scarcity that triggers a survival instinct.

The research by Juliano Laran, assistant professor of marketing, and Anthony Salerno, a marketing doctoral student, will be published next year in Psychological Science, the journal for the Association for Psychological Science.

Salerno became interested in the topic after reviewing studies that looked at New York City’s efforts to encourage people to make better food choices by requiring chain restaurants to include calorie counts on menus. In 2008, the city became the first in the country to do so. In general, the studies found no significant change in consumer behavior.

“People have the information to make a more healthy choice,” he said. “What’s happening?”

A New York University study published in 2009 looked at lower income neighborhoods in particular.

Salerno and Laran set out to answer the question, “Do perceptions that a person lives in a harsh environment influence their food choices?”

The two set up studies on the Coral Gables campus, including giving some students choices of high-calorie foods, while posting on a nearby wall words such as survival, withstand, shortfall and adversity. Students exposed to the words, or cues, ate more.