Evidence for the positive effects of intermittent fasting continues to mount: a new study shows that for people with obesity, it can lead to additional weight loss, as well as improved regulation for some of the body's key processes.
The research team, from institutions across Spain, wanted to build on previous studies of intermittent fasting – which includes time-restricted eating (TRE) – by looking at different schedules for eating and different types of fat loss.
"TRE appears to be a safe, well-tolerated, and feasible dietary approach for adults with overweight or obesity," write the researchers in their published paper.
The study involved 197 participants with overweight or obesity, aged between 30 and 60, followed over the course of 12 weeks. All the volunteers were put on the Mediterranean diet and given advice on nutrition.
Four sub-groups were created: one that restricted their eating to eight hours in the morning and afternoon, one restricted to eating within eight hours in the afternoon and evening, one restricted to eating during any eight-hour period chosen by the participant, and one with no eating restrictions aside from following the Mediterranean diet.
The data showed that intermittent fasting was associated with an average 2.4–3.1 kg (5.3–6.8 pound) weight loss above that of the control group that was given no TRE rules. There was little variation between the different time windows used in the TRE groups.
Magnetic resonance imaging (MRI) scans showed no differences across the groups in the reduction of the visceral adipose tissue (VAT) – fat surrounding our organs, that's strongly associated with cardiometabolic health.
However, the TRE group on the early schedule did show a bigger reduction in subcutaneous adipose tissue (SAT), the more visible type of fat just under the skin.
In addition, data from glucose monitors showed benefits for the early TRE group: their glucose levels were better regulated when they weren't eating and overnight, indicating the body was managing glucose in a healthier way.
The researchers think that stopping eating earlier in the day could give the body more time to properly process food and nutrients. It's another tick in the positives column for time-restricted eating as part of treatment for adults with overweight and obesity.
In Spain, where the study was conducted, more than half of all adults are classed as overweight or obese. It's also a country where eating happens all across the day – sometimes from a 7–8 am breakfast to as late as a 10 pm evening supper.
For many people, TRE offers an effective way of limiting energy intake in a way that's easy to stick to. However, there are still questions over how exactly it affects the body and what negative side effects could occur, so this study adds some useful detail to what we already know.
"Current literature suggests that TRE is well tolerated, has high adherence rates with minimal side effects and results in modest reductions in body weight and slight improvements in cardiometabolic health in individuals with overweight or obesity," write the researchers.
The research has been published in Nature Medicine.