A new study finds that an 8-hour eating window can help burn fat-but it’s safe?

New Study Finds an 8-Hour Eating Window May Aid Fat Burn—But Is It Safe?

A recent study from the University of Mississippi suggests that combining an 8-hour eating window with exercise helps healthy adults lose more fat while maintaining lean muscle mass, compared to exercise alone (source). This research, along with others, has contributed to the growing popularity of intermittent fasting. According to the IFIC 2024 survey, 13% of individuals following a specific diet reported using intermittent fasting as their method of choice (source).

One of the most common intermittent fasting methods is the 8-hour eating window, where all daily calories are consumed within an 8-hour timeframe, followed by 16 hours of fasting (source). As evidence continues to emerge, many are curious whether this approach could align with their lifestyle and health goals.

Is an 8-hour eating window right for you? This guide explores the pros and cons to help you decide if it’s worth trying.

What Is an 8-Hour Eating Window?

Time-restricted eating is a form of intermittent fasting. It involves consuming all daily calories within a set "eating window," typically ranging from 4 to 12 hours, and fasting for the remainder of the day (source).

The key difference between time-restricted eating and intermittent fasting is simplicity:

• Intermittent fasting is a broader concept that may include fasting for entire days or more.
• Time-restricted eating focuses on a daily schedule, ensuring you don’t go a full day without food.

How Does the 16:8 Method Work?

The 8-hour eating window, often referred to as the 16:8 method, is the most popular form of time-restricted eating. It involves consuming all daily calories within an 8-hour window and fasting for the remaining 16 hours (source).

Here’s how it typically works:

• Eating Window (8 hours): During this period, you can enjoy your usual meals—whether that’s breakfast, lunch, and dinner or just two larger meals.
• Fasting Window (16 hours): No calories are consumed during this time, but staying hydrated with water, tea, or black coffee is essential.

For example, you might eat between 7 AM and 3 PM or 9 AM and 5 PM. Outside this window, stick to zero-calorie beverages. Many find this schedule easy to follow, especially since it aligns with regular daytime eating and includes overnight fasting.

What Did the Latest Study Find?

The 2025 University of Mississippi study examined the effects of an 8-hour eating window combined with exercise (source):

• Study Type: A systematic review and meta-analysis of 15 studies over the past decade, focusing on how time-restricted eating impacts the body alongside exercise.
• Meal & Exercise Timing: Most participants ate during daylight hours and exercised within the eating window.
• Results: Those who combined an 8-hour eating window with exercise for at least 4 weeks lost slightly more body fat than those who only exercised, while both groups maintained lean muscle mass.
• Limitations: Most participants were already healthy, active adults with established exercise habits. Further research is needed for other populations.

In summary, the study suggests that time-restricted eating with exercise can improve body composition, particularly for healthy, active individuals.

Potential Benefits of Time-Restricted Eating

Time-restricted eating has become a hot topic in research, with several potential benefits:

• Reduced Calorie Intake: Limiting eating hours may naturally reduce calorie consumption without intentional restriction (source).
• Weight Loss Support: It may aid in weight loss and waistline reduction (source).
• Improved Metabolic Health: Fasting is linked to better insulin sensitivity, blood sugar control, and reduced inflammation (source).
• Heart Health: It may improve factors like body weight, blood sugar, blood pressure, and cholesterol levels (source).
• Gut Health: Fasting can support a healthy gut microbiome and strengthen the intestinal barrier (source).
• Energy Boost: Some report increased energy levels, likely due to improved insulin sensitivity (source).
• Simplified Diet: For some, it’s easier to follow than calorie counting or strict diet plans (source).

Health Risks and Considerations

While time-restricted eating can be beneficial, it’s not without risks:

• Headaches: Adjusting to fasting may cause headaches due to low blood sugar or caffeine withdrawal (source).
• Fatigue & Irritability: Initial fasting may lead to tiredness or irritability, though these effects are often temporary (source).
• Dehydration: Fasting can lead to reduced fluid intake, so prioritize hydration (source).
• Chronic Conditions: Fasting may not be safe for those with diabetes, heart disease, or other health issues (source).
• Digestive Issues: Breaking a fast can cause bloating or diarrhea, especially after longer fasts (source).

Who Might Benefit—And Who Should Avoid It

Time-restricted eating may help:

• Healthy, active adults looking to reduce body fat (source).
• Overweight or obese adults seeking weight loss (source).
• Individuals with conditions like type 2 diabetes or high cholesterol (with medical supervision) (source).

It’s not recommended for:

• Children under 18
• Pregnant or nursing women
• Individuals with type 1 diabetes or a history of eating disorders (source).

Tips for Trying It Safely and Effectively

If you’re considering an 8-hour eating window, follow these tips:

1. Start Slowly: Begin with a 12- or 14-hour window before transitioning to 8 hours.
2. Eat Mindfully: Focus on nutrient-dense, balanced meals during the eating window.
3. Stay Hydrated: Drink plenty of fluids during fasting and non-fasting hours.
4. Combine With Exercise: Pair time-restricted eating with exercise for optimal results (source).
5. Eat Earlier: Align eating with daylight hours to support circadian rhythms (source).
6. Track Progress: Use apps like MyFitnessPal to monitor your fasting schedule, meals, and exercise.

The Bottom Line

Time-restricted eating, such as an 8-hour window, can support weight management and metabolic health when paired with a balanced diet and active lifestyle (source). However, it’s not a one-size-fits-all solution. Consult your doctor or dietitian before starting, especially if you have underlying health conditions. They can help tailor a plan that’s safe and effective for you.

This post first appeared on the MyFitnessPal Blog.