The 16/8 diet. 16 hours of fasting, 8 hours of partying. Does it work?

Geschatte leestijd: 3 minuten Losing weight by only eating between 10:00 and 18:00 and then fasting. New research suggests it could be an effective method for weight loss. Without further restrictions in the diet.

16:8 diet

It’s called the 16:8 diet. A diet where you fast for 16 hours and ‘feast’ for 8 hours. The only restriction is that you only eat between 10:00 and 18:00. Before and after that, you can only drink water or other calorie-free beverages. The effectiveness of such a diet was examined in a study by the University of Illinois in Chicago. The findings were published in Nutrition and Healthy Aging [1]. The study involved 23 overweight people. On average, they were 45 years old with a BMI of 35. Between 10:00 and 18:00, they were allowed to eat whatever and however much they wanted. During the remaining hours, they could only drink water or other beverages without calories. The study lasted 12 weeks. The diet led to an average decrease in body weight of about three percent compared to a control group. In addition, the participants consumed about 350 kcal less and their blood pressure decreased.

“Easier diet”

According to the researchers, the most important message from this study is that you don’t necessarily have to count calories for a diet. Nor do you have to avoid certain types of food. They point to previous studies that have demonstrated the benefits of various diets based on fasting periods. Last year, we also wrote about alternate-day fasting, which was found to be as effective as creating a daily calorie deficit. On one day, 125% of the requirement was eaten (‘feast day’) and on the other day, 25% (‘fast day’). But that’s just one example, and earlier this year, Victor also wrote about alternate-day fasting, or intermittent fasting, in general. It’s recommended to read that article about the pros and cons of different forms of intermittent fasting. The researchers point out the successes of intermittent fasting, but note that in practice, it often proves difficult to fast entire days. Fasting at certain times of the day (such as early time-restricted feeding) may prove to be an easier form of fasting. ‘Their’ diet would in any case have fewer dropouts than in studies where fasting was done every other day. However, they emphasize that further research is needed to determine whether this form of fasting at certain times of the day is comparable in effect to alternating-day fasting. The weight loss in this study was slightly less than in other studies with intermittent fasting.

Still lighter but not less fat

What is mentioned but not really emphasized by the researchers is that no difference was seen in other aspects. Such as insulin sensitivity, cholesterol, but also fat mass. I wonder if you can really say that this diet works when it comes to obesity. I find the latter especially striking. I once described that fitness enthusiasts don’t want to ‘lose weight’ at all. ‘Losing weight’ simply means becoming lighter. However, becoming lighter should not be the goal; losing fat mass should be. If the participants in this study became lighter but did not lose fat mass, then you have to assume that they lost lean mass. A major variable in lean mass is of course muscle mass. So, translated freely, I read in this that the 16:8 diet (in this group) was more detrimental to muscle mass than fat mass. You shouldn’t want that at all. After all, muscle mass helps to absorb glucose and expend energy, processes that reduce the risk of obesity and diabetes. That fasting can be more detrimental to muscle mass than other diets was also mentioned in Victor’s article. Especially as an athlete, you can then wonder if it’s the smartest form of dieting. But everyone needs muscle mass. As mentioned for the absorption and expenditure of glucose, but especially for healthy mobility.

The diet that fits you and (therefore) works

The researchers rightly see this as a step towards further possibilities of such diets compared to other diets. It is mainly an indication that there is not one best diet that works for everyone.

When it comes to weight loss, people need to find what works for them because even small amounts of success can lead to improvements in metabolic health. Krista Varady, University of Illinois at Chicago

So, look for what works for you!

References

1. Kelsey Gabel, Kristin K. Hoddy, Nicole Haggerty, Jeehee Song, Cynthia M. Kroeger, John F. Trepanowski, Satchidananda Panda, Krista A. Varady. Effects of 8-hour time restricted feeding on body weight and metabolic disease risk factors in obese adults: A pilot study. Nutrition and Healthy Aging, 2018; 4 (4): 345
2. DOI: https://content.iospress.com/articles/nutrition-and-healthy-aging/nha170036