Periodic Fasting May Lower Risk of Diabetes and Heart disease

Benjamin D. Horne, PhD, MPH, FAHA, FACC Director, Cardiovascular and Genetic Epidemiology, Intermountain Heart Institute Adjunct Assistant Professor, Genetic Epidemiology Division, Department of Medicine, University of Interview with:
Benjamin D. Horne, PhD, MPH, FAHA, FACC
Director, Cardiovascular and Genetic Epidemiology, Intermountain Heart Institute
Adjunct Assistant Professor, Genetic Epidemiology Division, Department of Medicine,
University of Utah

MedicalResearch: What is the background for this study?

Dr. Horne: The Fasting II trial was a single-arm interventional trial of 24-hour water-only fasting among pre-diabetics with metabolic syndrome. The participants were adults with fasting blood glucose >100 mg/dL and at least two other components of the metabolic syndrome, including high triglycerides, low HDL cholesterol (the “good” cholesterol), high blood pressure, or high waist circumference. The participants were asked to fast once per week for 6 weeks, with multiple goals in this pilot study. This is the first interventional trial of fasting in people with pre-diabetes or diabetes.

MedicalResearch: What are the main outcomes of the study?

Dr. Horne: Compared to baseline, with other outcomes including changes in weight, LDL cholesterol, human growth hormone, and red blood cell count. These outcomes were chosen based on prior research that we and others have performed.  Another purpose of the trial was to evaluate whether individuals with pre-diabetes would be willing to comply with a fasting regimen, which was uncertain but necessary to understand for future, larger studies.

The study found that glucose was unchanged over the six weeks of the trial among 12 individuals who enrolled, but weight decreased a statistically significant although modest amount (1.6 kg) over the six weeks. Compliance with the study’s fasting intervention was 100% during the 6 weeks of the study and no adverse events were reported including fainting episodes, migraine headaches, or hypoglycemia. Importantly, we validated our 2011 finding that, during each 24 hour fasting period, the concentration of LDL cholesterol (the “bad” cholesterol) in the blood increases, while over the long-term (in this case, 6 weeks) the baseline LDL level dropped significantly (about 13%).

These findings indicate that fasting may directly reduce cardiac and metabolic risk factors and, thus, have a long-term impact on coronary disease and diabetes if fasting is engaged in repeatedly over a period of years. These results support several prior studies in which we showed that routine periodic fasting across the lifespan is, in fact, linked to a lower risk of diabetes and a lower risk of coronary artery disease.

The findings are similar to findings that a few studies of obese individuals have shown for intermittent fasting and alternate-day fasting, but this study’s results occurred from a less intense fasting regimen than those obesity studies, suggesting that the more rigorous or intense regimens may not be needed if fasting is used as a perpetual lifestyle change rather than a short-term diet. This is of importance because no studies to date have evaluated the potential harms of intense fasting regimens, including malnutrition, development of eating disorders, and incidence of cardiac hypertrophy.

MedicalResearch: What should clinicians and patients take away fro this report?

Dr. Horne: Clinicians and patients should realize that insufficient research has been performed to recommend fasting as a medical intervention. Fasting is not a quick fix for health problems. While it may be possible to fast safely using one of the fasting regimens historically practiced in various societies, the optimal fasting approach that appropriately balances the likely benefits and potential harms of the practice is unknown. Further, the amount of fasting needed to obtain the correct benefit for any specific individual is also unclear, but it is expected that intense fasting regimens are necessary only for those at high risk of chronic disease, while less intense regimens may be acceptable for apparently healthy individuals. Anyone wishing to begin a fasting regimen at this time should consult with their personal physician and engage the physician in an active monitoring program to ensure appropriate health is maintained.

MedicalResearch: What future research do you recommend as a result of this study?

Dr. Horne: Future research opportunities on the health effects of fasting are plentiful. The present study will serve as a basis for a much larger study of hundreds of pre-diabetics and should lead to additional interventional studies in other population segments. Further research is required to not only fully characterize the causal effects of fasting but to discover what fasting duration, frequency, and extended term of practice are needed to realize the benefits of fasting for each individual based on personal requirements.


Abstract presented at the 2014 American Diabetes Meeting

Fasting reduces cholesterol levels in prediabetic people over extended period of time



Last Updated on December 21, 2014 by Marie Benz MD FAAD