What is the best way to help busy people change their lives to become healthier? Should you lose a little weight first, and then start exercising? Or the other way around?

According to Abby King, the lead author of a study examining this question. "It may be particularly useful to start both at the same time. If you need to start with one, consider starting with physical activity first."

Focusing on changing exercise and diet at the same time gives a bigger boost than tackling them sequentially, the Stanford University School of Medicine team found. The data also show that changing diet first, as many weight-loss programs recommend, can make it more difficult to establish a consistent exercise routine.

The findings suggest that it may be easier to incorporate changes in eating habits than exercise, particularly when eating patterns are addressed at the beginning of a program.

Researchers selected 200 fairly inactive people over 45 for the year-long study. They were your average couch potatoes. None of the participants ate particularly well and all complained that they didn't have the time to make healthy diet and exercise choices.

The participants were divided into four groups. Each group received coaching and support by telephone: one group received exercise advice first, then nutrition advice was added after four months; a second group was given nutrition advice first, then exercise advice was added after four months. The third group received nutrition and exercise advice simultaneously. The fourth, control group, received no diet or exercise advice, only stress management advice.

The biggest challenge was figuring out how to get busy people to make time for exercise.

The people who tried to eat better and get more exercise simultaneously were a little slower to reach the exercise goals of the study, compared to the group that received exercise advice first, but eventually they were the most successful at meeting the national dietary and nutritional guidelines used for the study: 150 minutes of exercise per week; and five to nine servings of fruit and vegetables daily, with calories from saturated fats restricted to 10 percent or less of their total intake.

Those who started with exercise first did a good job of meeting both the exercise and diet goals, but not quite as good as those who focused on diet and exercise simultaneously.

The group that received nutrition advice first was not, overall, able to increase their exercise to the recommended levels by 12 months, while both the exercise-first and simultaneous groups achieved these exercise levels by the study's end.

The authors indicate that their findings suggest that it may be easier to incorporate changes in eating habits than exercise, particularly when eating patterns are addressed at the beginning of a program, because eating is already a scheduled activity. Adding physical activity to an already packed schedule may be more difficult. An initial program focus on both health behaviors from the beginning may show people the importance of making each a priority.

The study is published online in advance of print in Annals of Behavioral Medicine.