Intermittent fasting (IF) is the latest social media diet fad. It means basically what it says, you only eat in a specified time period, and the rest of the time you fast. There are a number of different variations include a 1 or 2 day a week, 24 hours a day fasting regimen, the 5:2 where you eat normally for 5 days and then cut your calories down to 500 a day for the other 2 days; and the most common method, the 16:8 or the 8:16, depending on your preference, but essentially, 8 hours of eating normal and 16 hours of not eating at all.
With 16:8 you get to choose the window of eating opportunity at your discretion, for example, 11 am to 7 pm. You can probably find more variations of IF but it can get a little much, although the principle of fast/don’t fast on a timer doesn’t change.
Fortunately, according to a new study1 published by University of Illinois at Chicago researchers in the journal Nutrition and Healthy Aging, daily fasting can be an effective tool in helping you reduce weight and lower your blood pressure. That’s good news for any diet.
The study did focus on weight loss in obese individuals. There is an obesity epidemic and there is a determination among health professionals to find the most effective and easiest ways to help an overweight population find a path to effective weight loss. Therefore, to study the effect of IF, researchers worked with 23 obese volunteers who had an average age of 45 and average BMI of 35.
Between the hours of 10 a.m. and 6 p.m. the dieters could eat what they wanted, but for the remaining 16 hours they could only drink the water or calorie-free beverages. The researchers followed the participants for 12 weeks.
When compared to a control group from a previous weight loss trial on a different type of fasting, the researchers found that those who followed the time-restricted eating diet consumed fewer calories, lost weight and had improvements in blood pressure.
On average, participants consumed about 350 fewer calories, lost about 3 percent of their body weight and saw their systolic blood pressure decreased by about 7 millimeters of mercury (mm Hg), the standard measure of blood pressure. All other measures, including fat mass, insulin resistance and cholesterol, were similar to the control group.
“The take-home message from this study is that there are options for weight loss that do not include calorie counting or eliminating certain foods,” said Krista Varady, associate professor of kinesiology and nutrition in the UIC College of Applied Health Sciences and corresponding author on the study.
“The results we saw in this study are similar to the results we’ve seen in other studies on alternate day fasting, another type of diet,” Varady said, “but one of the benefits of the 16:8 diet may be that it is easier for people to maintain. We observed that fewer participants dropped out of this study when compared to studies on other fasting diets.”
Varady says that while the research indicates daily fasting works for weight loss, there have not yet been studies to determine if it works better than other diets, although the researchers observed the weight loss to be slightly less than what has been observed in other intermittent fasting diet studies.
“These preliminary data offer promise for the use of time-restricted feeding as a weight loss technique in obese adults, but longer-term, large-scale randomized controlled trials [are required],” Varady and her colleagues write.
With all diets, there are zealots and skeptics. You’ll have to find your own way through the minutia of the different approaches and find what works for you. In the 16:8 model, you don’t have to think too much. You don’t have to count calories and you don’t have to try and work a schedule around your eating time. You’ve got to live your life, after all.
As for vindication of IF: the diet is probably one of the few instances where the science bros and the general enthusiasts will find some common ground and agreement, and it doesn’t require a degree in reading endless online research papers to figure out the factual basis of IF’s efficacy. We’d love to break bread with you on this one and celebrate but, too soon. We’ll catch you on our next 8 hour window.
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