An intermittent fasting regimen may be more effective at promoting weight loss than calorie restriction. Image credit: Dmytro Betsenko/Getty Images.
- Over the past few years, intermittent fasting has become a popular dietary pattern for helping to lose weight.
- There are different methods for intermittent fasting, including ones where you fast for certain hours in a day, and others when you fast for a number of full days during the week.
- A new study has found that 4:3 intermittent fasting may be more effective at helping lower weight over 12 months than a diet following daily calorie restriction.
Over the past few years, intermittent fasting has become a popular dietary pattern for helping to lose weight.
Also known as time-restricted eating, there are a number of different methods of intermittent fasting, including only eating for specific hours of the day, such as the 16:8 method (eat during an 8-hour window, fast for 16 hours each day).
And there are other methods that call for completely fasting or only consuming a minimal amount of calories for a number of days each week, such as the 5:2 method (eat as usual for 5 days, fast 2 days each week) and the
Now, a new study published in the journal Annals of Internal Medicine has found that 4:3 intermittent fasting may result in modestly greater weight loss over 12 months compared to daily calorie restriction.
For this study, researchers from the University of Colorado School of Medicine recruited 165 adults with overweight or obesity.
Study participants were randomly assigned to either follow 4:3 intermittent fasting or a daily calorie restriction diet for 12 months.
Participants in the 4:3 intermittent fasting groups were asked to restrict their calorie intake by 80% of their typical daily needs for 3 nonconsecutive days each week, and eat normally on the remaining 4 days with an emphasis on healthy eating.
Those in the daily calorie restriction diet were assigned a daily calorie goal that would lower their calorie consumption by 34.3%.
All participants received a free gym membership, group-based behavioral support, and information on calorie counting and targeting their dietary macronutrients. They were also encouraged to exercise for at least 300 minutes weekly.
Out of the original 165 participants, 125 successfully completed the study.
At the study’s conclusion, researchers found that participants in the 4:3 intermittent fasting group lost an average of 7.6% of their body weight over the 12 month period, compared to those in the calorie restriction group losing 5%.
More than half (58%) of those in the intermittent fasting group lost at least 5% of their body weight over 12 months, compared to 47% in the calorie restriction group.
Additionally, researchers discovered that participants in the intermittent fasting group had more encouraging changes in their cardiometabolic outcomes. These included systolic blood pressure, total and low-density lipoprotein (LDL) cholesterol levels, triglycerides, and fasting glucose levels.
Those in the calorie restriction group showed more favorable changes in diastolic blood pressure and high-density lipoprotein (HDL) cholesterol.
But they noted that many of these estimates in cardiometabolic changes lacked precision and ultimately yielded inconclusive results.
“Daily calorie restriction is the most commonly used dietary weight loss strategy,” Victoria A. Catenacci, MD, associate professor in the Division of Endocrinology, Metabolism, and Diabetes at the University of Colorado Anschutz Medical Campus and first author of this study told Medical News Today.
“However, adherence to a strategy where calories are restricted every day is challenging for many people,” Catenacci noted.
“Our results suggest that 4:3 intermittent fasting is an alternative dietary weight loss strategy that may be easier to adhere to over time, and thus may produce modestly superior weight loss compared with daily caloric restriction over one year, when supported by a behavioral weight loss program. Thus, 4:3 intermittent fasting should be considered within the range of evidence-based dietary weight loss approaches to be offered to people desiring weight loss.”
– Victoria A. Catenacci, MD
MNT had the opportunity to speak with Mir Ali, MD, a board-certified general surgeon, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, CA, about this study.
“The 4:3 intermittent fasting benefits were modest at best,” Ali, who was not involved in the research, pointed out. “Intermittent fasting has been shown in many studies to have beneficial effects. Further studies are necessary to define the optimal fasting schedule and delineate the health benefits. Unfortunately, no one method will work for all people.”
“Comparing different intermittent fasting regimens, and perhaps breaking down further by other variables such as age, gender, or ethnicity, may help define an optimal diet for a particular group of patients,” he added.
MNT also spoke with Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, about this study.
“The results of the study were not completely surprising as this type of intermittent fasting may act similarly to ‘metabolic confusion’ or ‘calorie shifting’ which essentially can catch the body by surprise and ‘shake things up’ by oscillating between a calorie deficit and sufficiency in addition to burning calories with exercise between intervals of rest and action,” Richard, who was likewise not involved in the study, explained.
“There have been research studies that have observed the positive benefits of these patterns, as in this study, but it is limited and overall success is highly variable and based on multiple factors unique to the individual and the study design methodology,” she added.
As the 4:3 intermittent fasting schedule calls for three days of fasting and four days of normal eating each week, that might be hard for some people to commit to.
So how can a person figure out the best intermittent fasting schedule for them?
For those interested in trying out intermittent fasting — and more specifically the 4:3 pattern — Richard advised readers to take into consideration several factors that could influence their success and sustainability, such as:
- prescription medications (insulin, high blood pressure medication, etc.) that could be impacted by drastically altering nutrient and energy intake
- mood/emotional and psychological well-being — are you the type of person who gets “hangry” or develops a headache after not eating for 6 to 8 hours?
- social wellbeing — will this pattern impede my ability to join friends and family for dinner parties, celebrations, or brunch? This can lead to isolation, resentment, disordered eating patterns, thoughts or possible binge-eating or related behavior.
And Richard said to take it one step at a time with these simple tips:
- have a support group or small group to try intermittent fasting together
- start slow — observe if fasting for 24 hours is doable, followed by 24 hours of eating 80% of recommended calories for a day, alternate for a week, then build up to 48 hours fasting, and so on
- keep in mind that nonfasting days are not “a-cheat-day-free-for-all” or “get out of healthy eating pass.”
You could also practice the 4:3 method by fasting or restricting calorie intake to 20% of your daily calorie needs for 24 hours on three nonconsecutive days per week, as was done in the study. Breaking up fasting days may make this regimen easier to stick to.
“We have long observed that in most instances, a slow, steady, informed, and intentional approach is often most advantageous,” Richard said. “Dietary patterns and activity along with mindfulness, neuroplasticity activities, and spiritual and social wellbeing for a well-balanced [life] seem to follow that logic.”
“Meeting with a Registered Dietitian Nutritionist (RDN) will allow clear information related to nutrient needs and the safety, applicability, and best practices in how implementing a pattern such as this can apply to an individual,” she added. “There are also unique genetic pathways and factors that may inhibit or support the success and desired outcomes using intermittent fasting, which an RDN can help an individual navigate and understand.”
