Research: Time restrictive eating for weight loss


Four versus six-hour restrictive eating for weight loss


Intermittent fasting is all the craze today. Many dieters are giving it a try to assist with weight loss and scientifically, it makes sense that fasting should work for weight loss if you can maintain it. The most common fast today is the 16:8 hour fast in which the dieter fast for 16 hours and eats for 8 hours. A recent study took a look at two different forms of fasting that use as 6 and 4 hour eating period instead​[1]​.

The study was undertaken to compare the effects of 4-hour time restricted feeding (TRF) period to that of 6-hour TRF period on body weight, body composition, and metabolic disease risk factors in adults with obesity. This is nto a new concept and is poretty much a simple fast. The researchers hypothesized that 4-hour TRF would produce the greatest decreases in body weight, fat mass, blood pressure, and insulin resistance. This would make send because it should result in lower caloric intake.

The researcher enrolled 49 adults with obesity. The subjects were randomized to 1 of 3 interventions for the 8 weeks trial. The 3 groups were 4-hour TRF (eating between 3:00 to 7:00 pm), 6-hour TRF (between 7:00 am to 3:00 pm), and the control (no fasting and eat as wanted). The two fasting groups would drink water or perform a water fast where no eating.

The results revealed that body weight decreased in the 4-hour TRF and 6-hour TRF groups with a loss of 7 and 5 pounds respectfully. The different was not significantly different, but 2 pounds is a significant difference for most. Fat mass, blood pressure and insulin sensitivity also decreased in the 4-hour TRF and 6-hour TRF groups versus controls. Both are markers of reduces obesity.

The bottom line: This is a unique approach to looking at fasting. This is the first trial to examine the effects of 4-hour vs. 6-hour TRF on body weight and metabolic disease risk factors. Both the 4 and 6-hour fast showed a significant weight loss effect. These preliminary data offer promise, but larger, longer-term trials are needed to confirm these findings and might illustrate a more significant effect between the fasting groups. I would also like to see an 8-hour group.

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  1. [1]
    S. Cienfuegos, K. Gabel, F. Kalam, M. Ezpeleta, V. Pavlou, and K. A. Varady, “Weight Loss Efficacy of 4-Hour Versus 6-Hour Time Restricted Feeding in Adults with Obesity,” Current Developments in Nutrition, pp. 584–584, May 2020, doi: 10.1093/cdn/nzaa047_004. [Online]. Available:
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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