Intermittent fasting using the 4:3 method leads to greater weight loss than traditional daily calorie counting, according to a breakthrough study that offers new hope for those struggling with diet adherence.

At a Glance

  • A University of Colorado study found that 4:3 intermittent fasting resulted in 7.6% weight loss compared to 5% with daily calorie restriction over 12 months
  • The fasting group restricted calories by 80% on three non-consecutive days per week with no restrictions on other days
  • Better adherence was observed in the fasting group with only 19% dropping out versus 30% in the calorie-counting group
  • Participants following intermittent fasting also showed more favorable changes in blood pressure, cholesterol, and glucose levels

How the Study Was Conducted

Researchers from the University of Colorado School of Medicine designed a randomized clinical trial involving 165 adults with overweight or obesity. Participants were divided into two groups: one following a 4:3 intermittent fasting pattern and the other practicing daily calorie restriction. The 12-month study, funded by the National Institutes of Health, aimed to compare the effectiveness of these different approaches to weight loss.

The intermittent fasting group restricted their calorie intake by 80% on three non-consecutive days each week, while enjoying unrestricted eating on the other four days. Meanwhile, the daily calorie restriction group followed a traditional dieting approach with a daily calorie goal designed to create a 34.3% energy deficit. Both groups received extensive support including group-based behavioral guidance, calorie counting instruction, dietary advice, and free gym memberships.

Superior Results with Intermittent Fasting

After a full year, the results showed a clear advantage for the intermittent fasting approach. The 4:3 group experienced an average weight loss of 7.6% of their body weight, significantly outperforming the daily calorie restriction group's 5% reduction. Additionally, 58% of participants in the fasting group achieved at least 5% weight loss, compared to only 47% in the calorie restriction group.

The benefits extended beyond just weight loss. Participants in the intermittent fasting group also showed more favorable changes in important cardiometabolic measures, including blood pressure, cholesterol levels, and fasting glucose levels. These improvements suggest that intermittent fasting may offer broader health benefits that could help reduce the risk of various chronic diseases.

Better Adherence: A Key to Success

One of the most striking findings was the difference in program adherence. The intermittent fasting group had significantly lower dropout rates, with only 19% quitting compared to 30% in the daily calorie-counting group. This suggests that many people find it easier to restrict calories severely for just three days a week rather than moderately restricting their intake every single day.

Researchers believe this improved adherence may be due to psychological factors. The 4:3 approach allows people to enjoy unrestricted eating most days of the week, creating less of a sense of constant deprivation. Dr. Danielle Ostendorf, one of the study researchers, described the 4:3 approach as potentially hitting "the sweet spot" – flexible enough for people to maintain their normal lives while still creating a meaningful calorie deficit.

Future Directions and Practical Considerations

The research team is now exploring the benefits of 4:3 fasting for specific groups, including breast cancer survivors and people with chronic conditions. They're also working to develop a comprehensive 4:3 intermittent fasting program that can be implemented in clinical and community settings, making this approach more accessible to the public.

For those interested in trying intermittent fasting, the researchers suggest starting with just one fasting day per week and gradually increasing to three, allowing the body time to adjust to the new eating pattern. It's important to note that the study participants received considerable support, including behavioral guidance and exercise recommendations, which likely contributed to their success.

While these results are promising, the researchers emphasize that weight loss approaches should be personalized. They call for further research on the safety of intermittent fasting for other populations, such as children, older adults, and people with certain health conditions. The findings of this study, published in the Annals of Internal Medicine, add valuable evidence supporting intermittent fasting as an effective alternative to traditional dieting approaches.