Fasting for two days and eating normally for the rest of the week - this is a variant of "intermittent fasting". An international team of researchers led by Dr Ruth Schübel from the German Cancer Research Centre (DKFZ) in Heidelberg has investigated this dietary trend.
Comparison of three dietary patterns
Schübel and her team analysed 150 overweight and obese test subjects over a period of one year. They compared three different dietary patterns: one group of test subjects followed the periodic fasting regime, eating five days a week as before and fasting on two days. A second group followed a conventional reduction diet and reduced their daily calorie intake by 20%. A control group followed the recommendations of the German Nutrition Society (DGE). All three groups adhered to the respective rules for 12 weeks. The scientists also documented the weight and health status of the study participants for 38 weeks afterwards. The biobank of the National Center for Tumor Diseases (NCT) Heidelberg provided important support for the research project: "Over the course of the study, we collected and stored a total of over 18,000 biosamples for the study," reports Dr Romy Kirsten. "Circulating biomarkers were analysed in the blood and urine samples of the study participants - these can indicate whether certain processes are currently taking place in the body or how pronounced they are. We later isolated DNA and RNA from subcutaneous fatty tissue." This provided Ruth Schübel and her research team with information about possible differences between the groups in the activity of certain key genes that play an important role in metabolism.
Health status improved by both diets
Intermittent fasting is no more effective than conventional diets, the researchers concluded. Unhealthy abdominal fat and fat deposits in the liver decreased with body weight in both the subjects in the fasting group and those on the diet. This improved the health of the test subjects in both groups equally. The scientists also found no difference between the diets in any of the other metabolic values analysed or in any of the biomarkers and gene activities investigated.
Scientific publication
Schübel R, Nattenmüller J, Sookthai D, Nonnenmacher T, Graf ME, Riedl L, Schlett CL, von Stackelberg O, Johnson T, Nabers D, Kirsten R, Kratz M, Kauczor HU, Ulrich CM, Kaaks R, Kühn T: Effects of intermittent and continuous calorie restriction on body weight and metabolism over one year: a randomized controlled trial. The American Journal of Clinical Nutrition 2018, DOI: 10.1093/ajcn/nqy196
Schübel R, Nonnenmacher T, Sookthai D, Gonzalez Maldonado S, Sowah SA, von Stackelberg O, Schlett CL, Grafetstätter M, Nabers D, Johnson T, Kirsten R, Ulrich CM, Kaaks R, Kauczor HU, Kühn T, Nattenmüller J. Similar Weight Loss Induces Greater Improvements in Insulin Sensitivity and Liver Function among Individuals with NAFLD Compared to Individuals without NAFLD. Nutrients. 2019 Mar 4;11(3). pii: E544. doi: 10.3390/nu11030544.
Schübel R, Sookthai D, Greimel J, Johnson TS, Grafetstätter ME, Kirsten R, Kratz M, Ulrich CM, Kaaks R, Kühn T. Key Genes of Lipid Metabolism and WNT-Signalling Are Downregulated in Subcutaneous Adipose Tissue with Moderate Weight Loss. Nutrients. 2019 Mar 16;11(3). pii: E639. doi: 10.3390/nu11030639.