Limiting Eating Times to Improve Health of People Who Work Around the Clock

In a study to improve the health of people who do shift work, researchers found that time-restricted eating was feasible for firefighters on 24-hour schedules and led to cardiometabolic benefits, particularly for those who had health risks when the study began. Shift work disrupts cycles of sleeping, eating, and activity, and it is associated with cardiovascular and metabolic disease. Thus, the researchers developed an intervention to reduce these health risks while being compatible with shift-work schedules and the nature of firefighting work, and they tested this in a clinical trial.

The intervention focused on time-restricted eating (TRE), limiting calorie intake to a 10-hour window per day most days of the week for 12 weeks. As an innovative strategy to inform recruitment and other aspects of the study design, the researchers consulted with fire departments and related organizations and did a 24-hour ride-along to understand the participants’ shift-work lifestyle. The study participants, 137 firefighters working 24-hour shifts, were recruited from a local fire-rescue department. Over 90 percent were male, reflecting the fire department’s demographics, and were from different racial groups and ethnicities; a majority were White though race was unknown for some participants. The researchers randomly assigned the participants to either the TRE group or a standard of care group. They advised both groups to follow a Mediterranean diet (e.g., eating more fruits and vegetables, olive oil, and fish); collected thousands of time-stamped food and beverage records, which the firefighters logged using an app on their smartphones; and examined health measures. The results showed that TRE was feasible, as the firefighters in the TRE group reduced their eating time from around 14 hours per day when the study began to about 11 hours per day. Among the subset of participants who had elevated risk factors before the intervention began, those in the TRE group had improved blood glucose (sugar) and diastolic blood pressure by the end of the study, compared to the standard of care group. Among all the participants, those in the TRE group had improvements in a blood lipid, VLDL, and better quality of life measures compared to the standard of care group. Some health improvements were seen in both groups (e.g., systolic blood pressure), possibly associated with dietary changes. No adverse events were reported.

These encouraging results show health benefits of time-restricted eating for people doing shift work and open the way to potential future studies with larger numbers of participants, including more women, and that explore longer-term health effects.