Mark P. Mattson, Ph.D. Adjunct Professor of Neuroscience Johns Hopkins University School of Medicine

Intermittent Fasting Effects on Health, Aging, and Disease Interview with:

Mark P. Mattson, Ph.D. Adjunct Professor of Neuroscience Johns Hopkins University School of Medicine

Dr. Mattson

Mark P. Mattson, Ph.D.
Adjunct Professor of Neuroscience
Johns Hopkins University School of Medicine What is the background for this study?

Response: The usual eating pattern of most people in modern societies is breakfast, lunch, dinner plus a snack(s) every day.   Animals used for most biomedical research – rats and mice – are usually fed ‘ad libitum’ (food is always available for them to eat).    During the past 25 years, myself and the many scientists who trained in my laboratory discovered that when rats or mice are fed intermittently such that they have no food every other day or eat only during a 4-6 hour time period each day, their overall health improves in many ways.  Animals on such intermittent fasting (IF) regimens exhibit signs of slowed aging and they live much longer than those fed ad libitum.

The editors of the New England Journal of Medicine invited me and Rafa de Cabo (a former postdoc in my laboratory at the National Institute on Aging) to write this review article for two main reasons.   First, there have been a sufficient number of studies demonstrating the health benefits of IF in humans and knowledge of the underlying mechanisms to justify a review article.  Second, many physicians are being asked about IF by their patients and the physicians are not privy as to if they should recommend IF and how to prescribe specific IF eating patterns and follow-up to increase the likelihood that the patient will be successful in changing their eating pattern. What are the main findings?

Response: In animals, intermittent fasting reduces blood pressure, abdominal fat and inflammation, improves glucose regulation and protects organs against injury and disease.  For example, IF can prevents cancer and greatly reduces the growth of tumors when cancer cells are transplanted into mice. IF protects heart cells against damage in a rat model of myocardial infarction.  Studies in my laboratory have shown that IF protects nerve cells in the brain against dysfunction and degeneration in animal models of stroke, Alzheimer’s disease and Parkinson’s disease.   These beneficial effects of intermittent fasting result from an enhanced ability of the cells to resist stress and disease.   Many recent studies in humans have confirmed that intermittent fasting improves glucose regulation, and reduces risk factors for diabetes, cardiovascular disease and stroke.  Evidence is also emerging that IF and the ketones produced during fasting can improve brain function and may protect against Alzheimer’s and Parkinson’s diseases.

Scores of studies have established that IF enables overweight people to selectively lose fat and improve risk factors for diabetes and cardiovascular disease.   Two such intermittent fasting eating patterns that are readily adopted are daily time-restricted eating in which food and caloric beverages are consumed only during a 4-6 hour time period each day, and a”5:2” eating pattern in which the person eats normally for 5 days each week and consumes only 500-700 calories the other two days.   After beginning the new IF eating pattern, it takes 2-4 weeks period for the brain and body to adapt.   Upon switching to IF, the person will experience hunger and irritability during the time period when they had previously been eating.  These initial ‘side effects’ will disappear during the adaptation period and their health indicators will be clearly improved during the first month of intermittent fasting. What should readers take away from your report?

Response: Research on intermittent fasting in humans is increasing rapidly.   It has been established that IF is beneficial for overweight people.  Intermittent fasting can also reduce risk factors for diabetes and cardiovascular disease in people with a normal body weight.  Intermittent fasting can be readily adopted by most people if they are motivated and are cognizant of the fact that it will take up to one-month for them to become fully adapted to the new eating pattern. What recommendations do you have for future research as a result of this work? 

Response: Future research should include clinical trials of intermittent fasting in patients with diabetes, cancer, cardiovascular disease and inflammatory disorders such as arthritis and multiple sclerosis.   Accumulating evidence from studies of animal models and of these diseases in humans suggests that IF is likely to prove beneficial for patients with these diseases.  Trials of IF in children and adolescents who are obese are also warranted. Is there anything else you would like to add? 

Response: Successful incorporation of intermittent fasting prescriptions into the health care system will require focused training of medical students and practicing physicians.  It will be particularly important to develop strategies that impact people of low socioeconomic status.   Education of parents will be particularly impactful.

No disclosures


Effects of Intermittent Fasting on Health, Aging, and Disease

Rafael de Cabo, Ph.D.,  and Mark P. Mattson, Ph.D.
December 26, 2019
N Engl J Med 2019; 381:2541-2551
DOI: 10.1056/NEJMra1905136 


Last Modified: [last-modified]

The information on is provided for educational purposes only, and is in no way intended to diagnose, cure, or treat any medical or other condition. Always seek the advice of your physician or other qualified health and ask your doctor any questions you may have regarding a medical condition. In addition to all other limitations and disclaimers in this agreement, service provider and its third party providers disclaim any liability or loss in connection with the content provided on this website.


Last Updated on January 2, 2020 by Marie Benz MD FAAD