A surprisingly small dose of exercise may deliver major health benefits for adults carrying excess fat around the waist. Moreover, in a four-month trial involving 315 adults with central obesity, researchers found that completing 75 minutes of brisk interval walking in a single weekly session reduced body fat, trimmed waistlines, and improved cardiovascular fitness about as effectively as splitting the same exercise across three days. Therefore, you may not need to work out every day to lose belly fat.
Researchers at the School of Public Health at the LKS Faculty of Medicine, the University of Hong Kong (HKUMed), have found that completing brisk interval walking once per week can significantly reduce body fat and improve cardiorespiratory fitness in adults with central obesity. The benefits were comparable to those seen in participants who exercised three times per week, which is the frequency commonly recommended in traditional exercise guidance.
The findings support once-weekly brisk interval walking as a practical therapeutic option for adults with central obesity, especially those who have difficulty fitting several workouts into their busy schedules. The landmark study was published in the prestigious journal Nature Communications.
Why a More Practical Approach to Reducing Body Fat Is Needed
Obesity is a chronic health condition involving an unhealthy buildup of body fat that increases disease risk. Fat that accumulates around the abdomen, known as central obesity or visceral fat, is especially concerning because it is strongly associated with cardiovascular disease, metabolic disorders like diabetes, and a higher risk of premature death.
Exercise plays a crucial role in managing obesity and offers a wide range of health benefits beyond weight loss. Even so, many people, particularly those living with obesity, struggle to maintain regular physical activity over time due to time constraints, demanding jobs, and family responsibilities.
Interval training alternates between more vigorous periods of exercise and lower-intensity periods of active recovery. Research has shown that it can be a highly time-efficient way to reduce overall body fat and dangerous visceral fat compared with continuous exercise performed at a moderate intensity. Most exercise recommendations call for interval training three days each week. That schedule may be difficult for people with limited time or restricted access to exercise facilities.
Previous research has suggested that a “weekend warrior” pattern, in which most weekly exercise is completed over one or two days, can still produce substantial health benefits. However, there has been relatively little evidence showing whether interval training remains effective when concentrated into a single weekly session.
One Session Versus Three: How the Trial Was Conducted
Professor Parco Siu Ming-fai, Professor and Head of Division of Kinesiology at the School of Public Health, HKUMed, said it was important to determine whether once-weekly interval training could match the results of a traditional three-session schedule and provide a more accessible alternative for patients. From September 2021 to September 2024, the HKUMed team carried out a rigorous randomized trial in Hong Kong involving 315 Chinese adults aged 18 or older. All participants were overweight and had central obesity with a large waist circumference.
Participants were assigned to one of three groups. One group completed interval training once each week (75 minutes in one go), another completed interval training three times each week (25 minutes per session), and the third served as a control group. The control group took part in a 2.5-hour health education session every two weeks for four months but did no structured exercise. Both exercise groups completed a total of 75 minutes of brisk interval walking each week. Researchers measured body fat using dual-energy X-ray absorptiometry (DEXA) at three stages: before the program began, after 16 weeks, and at 32 weeks for follow-up.
Similar Fat Loss and Fitness Benefits From Once a Week
At the 16-week assessment, both interval training groups showed similar and significant improvements compared to the control group. Participants who exercised once per week and those who exercised three times per week both reduced total body fat mass, body fat percentage, and waist circumference. Both groups also substantially improved their cardiorespiratory fitness, a key marker of heart health.
“While thrice-weekly interval training remains a commonly recommended approach for the therapeutic management of excess adiposity, our findings show that once-weekly interval training offers similar benefits and represents a practical exercise strategy,” said Professor Siu. “For many adults with central obesity who struggle to balance work, study, family and other commitments, time constraints are a primary barrier to exercising multiple days per week,” he added.
“Instead of relying solely on high-frequency exercise prescriptions, once-weekly interval training can be considered a feasible and effective alternative,” Professor Siu emphasized. Consequently, the weekend warrior approach is now backed by strong evidence for belly fat loss.
The study was led by Professor Parco Siu Ming-fai. The co-first authors were Dr. Leung Chit-kay and Mr. Joshua Bernal, both from the same School of Public Health.
How to Do Brisk Interval Walking Correctly
Brisk interval walking means alternating between fast walking at 70-80% effort where talking becomes difficult, and slower recovery walking. For example, walk briskly for 3 minutes, then slowly for 2 minutes, and repeat for 75 minutes total. This variation burns more fat and improves fitness faster than steady walking.
Analysis: Quality Over Frequency for Belly Fat
This HKU trial fundamentally challenges the idea that you must exercise 3 to 5 days a week to see results for central obesity. For busy adults, 75 minutes of focused, brisk interval walking done properly once a week can be just as effective for reducing total body fat, trimming the waistline, and boosting heart fitness. Therefore, consistency in doing that one session is far more important than worrying about frequency.
FAQ
1. Can 75 minutes of walking once a week reduce belly fat?
Yes, a randomized trial of 315 adults with central obesity published in Nature Communications found that 75 minutes of brisk interval walking once a week reduced total body fat mass, body fat percentage, and waist circumference as effectively as three 25-minute sessions.
2. What is brisk interval walking?
Brisk interval walking alternates between vigorous fast walking where you are slightly breathless and lower-intensity slow walking for recovery, for example 3 minutes fast followed by 2 minutes slow, repeated for 75 minutes.
3. Is weekend warrior exercise effective for obesity?
Yes, the HKU study supports the weekend warrior pattern, showing that concentrating weekly exercise into one or two days still produces major benefits for fat loss and cardiorespiratory fitness in adults with central obesity.
4. How was body fat measured in the HKU study?
Researchers used dual-energy X-ray absorptiometry (DEXA), the gold standard for body composition, at baseline, 16 weeks post-intervention, and 32 weeks follow-up to accurately measure fat mass and body fat percentage.
Disclaimer: This article is for general informational and educational purposes only and is based on research by HKUMed published in Nature Communications. It does not constitute medical advice, diagnosis, or treatment. Central obesity is a medical condition associated with cardiovascular risks. Brisk interval walking may not be suitable for everyone, especially those with heart conditions, joint problems, or severe obesity. Please consult a qualified healthcare professional or physiotherapist before starting any new exercise program. Our news portal and its authors assume no liability for actions taken based on this information.
