Timothy Gubler and Lamar Pierce from the Olin Business School at Washington University in St. Louis looked at which employees were most likely to "correct poor physical health indicators revealed during an employer-sponsored health examination."
According to the study's press release, workers who were contributing to their employer-sponsored retirement accounts made the effort to correct poor health indicators, like blood glucose and cholesterol, 27% more than non-contributors.
The researchers examined data from eight different industrial laundry locations to determine who did and didn't fund their 401(k)s, then gave the workers health screenings and sent the results to both patients and their primary doctors, along with some information on "risky health behaviors and anticipated future health risks."
Over the course of two years, the researchers tracked these employees to see a) whether they made any effort to improve their health, and b) whether their efforts were reflected in their saving for the future via 401(k)s.
And indeed, it was many of the same people who were proactive both in saving for retirement and improving their health. While the researchers didn't measure it specifically, they explain that neglecting retirement funds and good health may have something to do with a cognitive bias called "time discounting," which causes us to choose smaller, immediate rewards (cookie!) over larger rewards later down the line.