When it comes to providing incentives for people to make healthy lifestyle choices, mobile devices to track diet and exercise can help, but the real motivator might be good old, hard cash.
Researchers from Northwestern University's Feinberg School of Medicine in Chicago gave handheld personal digital assistants to 204 adults at risk of developing multiple chronic diseases due to lifestyle and diet.
They also offered cash payments of as much as $175 for study participants to meet and then maintain goals for physical activity, eating fruits and vegetables and limiting intake of saturated fat over a three-week period. Additional money was available for uploading data during a five-month follow-up phase, and the monthly payouts increased the longer people continued to report data, according to an article in the May 28 issue of the Archives of Internal Medicine.
For the study, subjects were given PDAs to record and monitor their food and activity choices, as well as to receive coaching from health professionals. The participants also could use the devices to look up the impact each choice might have on their risk of developing cardiovascular disease, cancer, diabetes or other serious health conditions. To keep people honest, the researchers asked subjects to submit grocery receipts, data from accelerometers and urine samples, though those measures were not included in the study.
An impressive 98 percent of study subjects completed the entire study, and the results were encouraging, the researchers report. The mean number of servings of produce jumped from 1.2 per day at the start of the test period to 5.5 three weeks later, though the level fell back to 2.9 per day by the end of the follow-up. Calories from saturated fat dropped from a mean level of 12 percent to 9.4 percent during the test, then settled at 9.9 percent after five months.
Participants also cut the number of daily minutes of sedentary leisure—such as watching TV or playing computer games—from 219.2 to 89.3 in the three weeks. After the follow-up, the mean number of minutes was just 125.7. "Although they were neither asked nor reinforced to maintain eating or activity improvements, 86.5 percent of the 185 participants from whom exit interviews were obtained said they 'definitely' or 'somewhat' tried to maintain gains," the report says.
"This study demonstrates the feasibility of changing multiple unhealthy diet and activity behaviors simultaneously, efficiently, and with minimal face-to-face contact by using mobile technology, remote coaching, and incentives," according to the Northwestern team. However, they recognized some shortcomings of the study. For one thing, nearly three-quarters of participants were women, so it is unclear if men would be as compliant.
"Also, the amount of the financial incentive was larger than would be feasible for some settings. It remains to be determined whether such rapid and full acquisition of behavior change targets would occur with smaller incentives," they say.
A story in the Times of Northwest Indiana (Munster, Ind.) says that the Feinberg School is getting ready to conduct follow-up research using Android smartphones.
