Get up off the couch and go buy some fruit and vegetables. According to a recently published study, that's a road to better health that's easiest for most people to take. A little financial incentive doesn't hurt either.

It's hardly news that Americans eat too much saturated fat, too little fruit and vegetables, sit too much and don't exercise nearly enough. But it would be news if someone found out to get them to change these habits for the better. And researchers at Northwestern University may have found the way.

As an incentive, the participants could earn $180 for meeting their goals for the two habits they were trying to improve during the first three (target) weeks of the study.

The researchers looked at people with all four of these unhealthy habits who wanted to change them. And they tested which pair of behaviors--one dietary and one physical--was easiest for people to improve. The pairs were increase fruit/vegetables and sit less, increase fruit/vegetables and increase exercise, lower saturated fat and sit less, and lower saturated fat and increase exercise.

By far, people found it easier to decrease their couch time and increase their fruit and vegetable intake, making major changes within three weeks. These changes persisted, though not as strongly, for a full 20 weeks, the length of the study. As a bonus, people also lowered their saturated fat intake slightly.

It might just be time to change the formula for better health from "eat less and exercise more" to "get up off the couch and start eating more fruit and vegetables."

As an incentive, the participants could earn $180 for meeting their goals for the two habits they were trying to improve during the first three (target) weeks of the study: eating five or more servings of fruit and vegetables daily, lowering saturated fats to below 8% of their daily calorie total, decreasing sedentary leisure time to under 90 minutes per day and/or increasing moderate or vigorous physical activity to at least 60 minutes per day. All information was self-reported.

After the first three weeks, participants could earn an additional $30-$80 by continuing to upload data to the researchers for the next 17 weeks (follow-up), though there was no longer any need to actually meet any dietary or activity goals to receive this payment.

For the decrease sitting/increase fruit and vegetable group, their fruit and vegetable consumption started at 1.9 servings per day, rose to 5.5 during the three week target phase and dropped off to 2.9 during the 17-week follow-up phase. Their sedentary leisure time went down from an initial 219.2 minutes to day to 89.3 during the target phase and 125.7 during follow-up. And their saturated fat consumption as a percent of daily calories went from 12% to 9.4% to 9.9%.

In other words, people were able to make significant healthy changes during their first three weeks. And while these improvements slacked off a bit afterwards, they still remained 17 weeks later, five months after the start of the trial.

Improvements were also seen in the other three test groups, but they weren't as large.

Every hour you're not sitting on the couch watching TV is an hour that you're not eating chocolate chip cookies, chips or the other tempting snacks that are a standard part of TV time. And while the researchers didn't actually test this, it seems reasonable that less couch time is the first step towards an overall healthier lifestyle and probably the easiest step to take.

So get up off the couch and go invest in some fruit and vegetables.

An article on the study appears in Archives of Internal Medicine.