In the Interfast study, scientists from the University of Graz and the Medical University of Graz are jointly investigating the effects of intermittent fasting – more precisely, “alternate-day fasting” – a method in which you alternate between not eating anything for a day and eating everything for an unlimited period the next day. The first results have been published in the renowned journal Cell Metabolism. In addition to weight loss after four weeks, intermittent fasting also had a positive effect on many health indicators, such as cholesterol, blood pressure, abdominal fat and inflammatory parameters.
Sixty healthy volunteers in the Interfast project were divided into two groups. One group practised intermittent fasting for four weeks, and the other maintained their current lifestyle. “The study was supplemented by an additional 30 subjects who had already been practising alternate-day fasting for more than six months”, explain study directors Frank Madeo from the University of Graz and Thomas Pieber and Harald Sourij from the Medical University of Graz. “This made it possible for us to take a first, unique look at the long-term effects of alternate-day fasting.” The researchers wanted to investigate the effects of intermittent fasting on both body weight and molecular mechanisms in healthy subjects. The strict observance of the fasting days was closely monitored by means of continuous glucose measurement.
The results of the study were clear. “Within four weeks, the study participants had already reduced their body weight by an average of around 3.5 kilograms, with the average initial weight being 76 kilograms,” reports Thomas Pieber. The researchers saw not only a clear weight reduction among the fasting participants; they also registered an increase in ketones. “These are produced as a by-product of fat burning in carbohydrate deficiency and are suspected to have anti-ageing effects. Furthermore, in the fasting cohort, we saw a reduction of specific amino acid levels, cholesterol, systolic blood pressure, abdominal fat and inflammation parameters. Reductions in all these effects are associated with positive health impacts”, Frank Madeo says regarding the insights gained into molecular mechanisms. In addition, the researchers found a mild reduction of the thyroid hormone T3 in the fasting patients and a simultaneous increase in the thyroid-stimulating hormone TSH. This has already been associated with longevity in numerous studies.
“Intermittent fasting is a very simple but extremely effective dietary principle,” says Harald Sourij, who is looking forward to future research projects. The Interfast-2 study will begin building on the current results in autumn. It will investigate intermittent fasting in patients with type 2 diabetes who already require insulin therapy.
Publication: Stekovic, Hofer, and Tripolt et al. “Alternate day fasting improves physiological and molecular markers of aging in healthy, non-obese humans”, Cell Metabolism, DOI: 10.1016/j.cmet.2019.07.016