Intermittent fasting diets, where you incorporate periods of fasting (or near-fasting), are all the rage in the health world right now.
Previous research has shown the diet may decrease risk factors for a multitude of diseases, including diabetes, heart disease and cancer.
But can intermittent fasting really help you drop the weight? And how?
According to a new study published this week in the journal Cell Research, the answer is: yes.
The research comes from pathobiology scientists at the University of Toronto in Ontario, Canada, who used mice to understand the mechanisms of intermittent fasting.
For their 16-week study, the team put mice into two separate groups: an intermittent fasting group and a control group.
The mice in the IF group received no food for a day and were then fed for the next two days.
The control group was fed everyday and both groups were fed the same number of calories during those 16 weeks.
In the end, the mice in the IF group weighed much less than the mice in the control group.
“We found that an intermittent fasting regimen not only prevented obesity in mice, but also improved metabolism by changing the quality of fat in the body,” researcher Hoon-Ki Sung told MedicalResearch.com.
According to Sung, during the fasting period of the IF diet, anti-inflammatory immune cells converted inflammatory fat or “white fat” to “brown-like” fat, meaning bad fat was converted to good fat.
During those periods of fasting, the body undergoes an increase in vascular growth factor, which helps form blood vessels and activate those anti-inflammatory immune cells, lead researcher Kyoung-Han Kim said in a press release.
The IF diet also stabilized their glucose and insulin systems.
“The results are exciting, because they show that weight loss is not the sole benefit of fasting. Fasting also restores the dual function of fat cells, which is to store energy and to release energy,” Sung said.
It worked for mice. Does it work for humans?
According to Sung, testing the IF regimen with mice or in any animal model is “very different from what is practical and safe for humans.”
Previous research has found IF to be effective for weight loss, but many of those studies followed participants for a few months.
The first long-term, randomized study on alternate-day fasting was published in May in the journal JAMA Internal Medicine and showed that the regimen may not necessarily be much more effective than normal dieting.
During that study, 30 of the 100 participants dropped out, many of whom had trouble sticking to the IF diet.
In the end, the data suggested both normal calorie-restricted diets and alternate-day diets proved effective for weight loss.
The new research provides evidence of a metabolic benefit to the fasting period in the IF diet. Future research should assess the regimen in humans and how it could potentially prevent obesity and other metabolic diseases, the scientists said.
“Intermittent fasting without a reduction in calorie intake can be a preventative and therapeutic approach against obesity and metabolic disorders," Kyoung-Han Kim, of The Hospital for Sick Children in Ontario, Canada, said in a press release.