Researchers studied 104 middle-aged women who were overweight to see if eating only during an 8-hour window each day, combined with exercise, could help them lose fat. The women were divided into four groups: one that only changed eating times, one that only exercised, one that did both, and one that made no changes. After 12 weeks, the women who combined the eating schedule with exercise lost the most fat—about 6 pounds more than those who didn’t make any changes. This study shows that combining these two approaches together works better than doing either one alone.

The Quick Take

  • What they studied: Whether eating only during an 8-hour window each day, with or without exercise, helps middle-aged women lose body fat
  • Who participated: 104 women between ages 40-60 who were overweight or had obesity, living in Hong Kong. They were randomly split into four equal groups of 26 women each
  • Key finding: Women who combined the 8-hour eating window with aerobic exercise lost about 6.3 pounds more fat than women who made no changes. The combination worked better than either approach alone
  • What it means for you: If you’re a middle-aged woman looking to lose weight, combining a structured eating schedule with regular exercise may be more effective than trying just one approach. However, this was a small study in one location, so results may vary for different people

The Research Details

This was a carefully controlled experiment where 104 women were randomly assigned to one of four groups. One group ate only during an 8-hour window each day (like noon to 8 PM), another group did aerobic exercise three times per week, a third group did both the eating schedule and exercise, and the fourth group made no changes. The researchers measured how much body fat each woman had at the start and after 12 weeks. The women didn’t know which group was being measured differently (the researchers kept that hidden), which helps prevent bias in the results.

The study took place over about 10 months in Hong Kong, with women joining from September 2023 through July 2024. All 104 women who started the study completed it and were included in the final results. The researchers looked at several health measurements, but the main focus was on how much fat mass (not just overall weight) each group lost.

This type of study design is considered very reliable because it randomly assigns people to different groups, which helps ensure the groups are similar at the start. By having a control group that made no changes, researchers could see the true effect of the eating schedule and exercise. Measuring this in real life (not in a lab) makes the results more relevant to how people actually live

This study has several strengths: it was published in a highly respected journal (Nature Communications), all participants completed the study, the dropout rate was very low, and people stuck with the program (83-87% adherence). The study was also blinded, meaning the people measuring results didn’t know which group participants were in. However, the study only lasted 12 weeks, included only women in one location, and had a relatively small number of participants, so results might be different for men, other age groups, or other populations

What the Results Show

The group that combined the 8-hour eating window with exercise lost the most fat. Specifically, they lost 2.85 kilograms (about 6.3 pounds) more fat than the control group that made no changes. This difference was very unlikely to happen by chance alone.

When comparing the combined approach to each single approach, the results were clear: the combination beat the eating schedule alone by 1.56 kg (3.4 pounds) and beat exercise alone by 2.01 kg (4.4 pounds). This means that doing both together created a stronger effect than either one by itself.

The exercise-only group and eating-schedule-only group both showed benefits compared to the control group, but the combined approach was noticeably better. All three intervention groups showed improvements in other health markers related to metabolism and body composition, though the combined group had the most improvement.

Beyond just fat loss, the study measured other important health markers. Women in the combined group showed better improvements in how their bodies handle blood sugar, improvements in cholesterol levels, and better overall metabolic health compared to the other groups. These secondary benefits are important because they suggest the approach helps with overall health, not just weight loss

Previous research has shown that both time-restricted eating and exercise separately can help with weight loss. This study adds important new information by showing that combining them works significantly better than either approach alone. The finding that the combination is more effective than the sum of individual effects is particularly valuable and suggests these two approaches work together in complementary ways

The study only lasted 12 weeks, so we don’t know if the results continue over longer periods. The study included only women aged 40-60 in Hong Kong, so results might be different for men, younger or older people, or people from different backgrounds. The study had 26 people in each group, which is relatively small. We also don’t know if people could maintain these changes after the study ended. The study didn’t look at different types of exercise or different eating windows, so we can’t say if other combinations might work better or worse

The Bottom Line

For middle-aged women who are overweight or have obesity, combining an 8-hour eating window with regular aerobic exercise appears to be an effective approach for losing fat and improving metabolic health. This recommendation has moderate confidence because the study was well-designed but relatively small and short-term. Women should consult with their doctor before starting any new exercise or eating program, especially if they have existing health conditions

This research is most relevant for women aged 40-60 who are overweight or have obesity and are looking for ways to improve their health. The findings may also be relevant for men and other age groups, but this study specifically tested women in this age range. People with certain medical conditions, those taking specific medications, or pregnant women should talk to their doctor before trying this approach

The study showed results after 12 weeks, which is about 3 months. Most people might expect to see noticeable changes in how their clothes fit and energy levels within 4-8 weeks, with more significant fat loss visible after 12 weeks. However, individual results vary, and some people may see changes faster or slower depending on their starting point and how well they stick with the program

Want to Apply This Research?

  • Track your eating window daily (record start and end times of your 8-hour eating period) and log aerobic exercise sessions (type, duration, and intensity). Measure body weight weekly and take body measurements (waist, hips, chest) every 2 weeks to monitor fat loss progress
  • Set a specific 8-hour eating window that fits your schedule (for example, 12 PM to 8 PM), schedule three aerobic exercise sessions per week at consistent times, and use the app to send reminders for both eating window start/end times and exercise sessions. Track adherence percentage to stay motivated
  • Create a dashboard showing weekly weight trends, monthly body measurement changes, exercise frequency and duration, and eating window adherence percentage. Set monthly goals for exercise sessions completed and eating window consistency, and review progress every 4 weeks to adjust the approach if needed

This research suggests that combining time-restricted eating with exercise may help middle-aged women lose fat, but individual results vary. This information is for educational purposes and should not replace professional medical advice. Before starting any new eating schedule or exercise program, especially if you have health conditions, take medications, or are pregnant or breastfeeding, consult with your doctor or a registered dietitian. The study lasted only 12 weeks, so long-term effects are unknown. Results in this study were from women aged 40-60 in Hong Kong and may not apply to all populations.