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Transcript: Intermittent Fasting: What is it? Recommend it? Part 1

Jan 30, 2016

This is part 1 of a 3-part video transcription.

Transcript Part 2 | Transcript Part 3


To view the video series, go here.

Steve Freed:               This is Steve Freed with Diabetes in Control and we have a special guest with us today. We’re here with Dr. Mark Mattson who is Chief of the Laboratory of Neurosciences at The National Institute on Aging Intramural Research Program at the NIH. He’s also a professor of neuroscience at Johns Hopkins University.

Maybe we can start off with you telling us what kind of research that you’re involved in.


Dr. Mark Mattson:     I’m a neuroscientist and studying brain aging and neurodegenerative disorders, particularly Alzheimer’s and Parkinson’s diseases, and we work mainly with animal models and at the level of brain cells themselves and trying to understand why in Alzheimer’s and Parkinson’s certain neurons become dysfunctional and degenerate leading to the characteristic symptoms in those disorders.


Steve Freed:               Well, that sounds kind of interesting. It sounds like you might be able to make a difference in some of those diseases, but let me first ask you a question. In a paper published in the journal Cell Metabolism titled Fasting, Molecular Mechanisms and Clinical Applications in the first paragraph it states “In rodents intermittent  fasting protects against diabetes, cancers, heart disease and neurodegeneration while in humans it helps reduce obesity, hypertension, asthma, rheumatoid arthritis. Fasting has the potential to delay aging and help prevent and treat diseases.” This was published in February 2014.

Has anything changed in regards to using intermittent fasting as a possible treatment for type 2 diabetes and those other disease mentioned in the published study?


Dr. Mark Mattson:     Well, there’s a lot of active research going on in this area moving to studies of human patients. Most of the work is in animal models but there are initial studies that support those statements in human populations. And most of these studies involve what we call intermittent fasting approaches in which, for example, a person two days a week will eat nothing or very little on those days and stay hydrated.

And another approach is restricting the time window each day during which food is consumed, for example six to eight hours. It turns out most Americans put something caloric in their mouth when they get up and then they eat meals, snacks and they eat something right before they go to bed, so the only time they’re not taking in anything caloric is when they’re sleeping.

And it turns out one reason that we think that fasting, even for relatively short time periods like 16 or 24 hours may be beneficial for diabetes is because it greatly improves insulin sensitivity established in numerous animal studies and in at least half-a-dozen human studies.

But also if you eat regular meals – three meals a day plus snacks – you never tap into your fat stores as an energy source because every time you eat energy goes into your liver and that’s always used first; so with fasting, even relatively short fasts, you shift to burning fats and this seems to contribute to the beneficial effects on body weight and the, if you will, anti-diabetic effects of intermittent fasting.

Steve Freed:               Okay. To me the research sounds kind of fantastic because we might have the answer here for preventing diabetes. And I would think the NIH would come up with the same thought process and I can’t be the first one to think of that. And there’s 90 million people out there with pre-diabetes, 30 million with diabetes and 25 percent don’t even know they have it, and out of the people with pre-diabetes 90 percent don’t even know they have it, and here we have something that could possibly prevent diabetes.

You know, it’s a nutritional disease almost, you know, people overeating, eating the wrong foods, eating all those carbohydrates. And you would think that if people took two days off of eating each week and followed those people for ten years they would be healthier, thinner and they wouldn’t have diabetes. So where are we with – there’s got to be something going on at NIH because we know the drug companies aren’t going to pay for this research.


Dr. Mark Mattson:     That’s exactly right. Well, we’re at a point now where we know exercise can protect against diabetes, and the NIH certainly is an advocate of regular exercise and there’s a lot more data, particularly in controlled human studies with exercise and that’s very clear.

I personally would agree with you that the findings with fasting are very strong and supportive of the idea that this could be an approach for reducing risk or preventing diabetes in most people, but the NIH isn’t to the point yet when they want to actually make a specific recommendation.

However, you know, as we mentioned this is something no one will make money from and in fact food companies will lose money if people don’t eat as much.   However, these kinds of eating patterns that I mentioned – say two days a week fasting or restricting food intake each day to a limited time window – are very safe and anyone can try them.

We’ve found in the human studies that I’ve been involved with that it takes up to a month for people who have never done these intermittent fasting diets before to get adapted to them, and it’s analogous to exercise if you’ve been sedentary for years and then you go out and run three miles: you’re not going to feel very good, it’s going to take you a month to get in shape.

We find it’s kind of similar with intermittent fasting, it takes a little while to get used to it, but once people get used to it – at least the people in the studies we’ve done, which involves a couple-hundred subjects – once they get used to it they’re feeling better and they often stick with it even for years. So it’s kind of a lifestyle approach that if someone can – you have to have motivation – but if you can try to stick with it for a month or so you can adapt to it and be feeling better and maybe even feel bad if you start eating regular meals every day again.

Steve Freed:               Let’s say I wanted to start this to improve my health can you kind of break it out as to what you actually have to do? I mean how many calories should you be eating on those two days, what time of the day, and when can you expect to see actual results?


Dr. Mark Mattson:     Yeah, well, I think one really good aspect of this approach is that \ there are several different weekly regimens that someone can follow that fit into their daily and weekly routines.

So for example for two days a week fasting, one approach would be to not eat breakfast and then eat a moderate lunch – maybe you have a lunch meeting and it’s kind of, not impolite, but feels a little uncomfortable if everyone else is eating and you’re not, so one approach there might just to be eat lunch only and then – so then you’ve only maybe had 500 calories those two days each week.

A key thing though is you have to make sure not to overeat on the other five days: so just eat normally, a healthy diet. And another routine that may suit other people better would be to skip breakfast and lunch – and actually I do this quite a bit – and then if you can workout say midafternoon then eat, work a little more, go home, eat some more and then stop eating by 8:00 PM – don’t eat anything after 8:00 – and do that three or four or five days a week maybe on the workdays, and for a lot of people that’s doable because you can get up in the morning, go to work and then work through lunch and take a break, workout, and then eat – and so that approach you’ve then restricted the time period that you eat to approximately six hours which means you’ve gone 18 hours with no food and that’s plenty of time to get the shift in energy metabolism that we think is important for lowering body fat and overall weight.

And interestingly, with these kinds of diets in animals and human subjects they retain lean muscle mass – you’re not going to lose muscle weight at all: the shift in energy metabolism results in selective loss of fat.


Steve Freed:               But what if you generate ketones? Is that dangerous for a type 2? We know it’s dangerous for a type 1 but –


Dr. Mark Mattson:     No, ketones are good. When I talk about this a lot of times I point out that from an evolutionary perspective not eating for a day or two is very normal for many animals in the wild and for our human ancestors before the agricultural revolution. We are, through evolution, designed to function well when we’ve been fasting for even several days. And it’s very important that the ketones go up during the fasting period because ketones are a very good source of energy for muscle and brain cells. Obviously if you don’t eat much and you’re mobilizing fats then your glucose levels stay low. So through evolution this generation of ketones is a way that allows cells to obtain energy from the ketones during the fasting period.

You know, we study the brain and it’s very clear that ketones are good for nerve cells, and in fact ketogenic diets – the same can be done with fasting – are used for treating patients with epilepsy whose seizures don’t respond to drugs. The standard of care is to put them on a ketogenic diet but the same effect would be obtained with fasting because the endogenous ketones produced in your liver will suppress the seizures.

And in fact one of the first studies we published was showing that intermittent fasting can protect the brain of rats against seizures in an epilepsy model.


Steve Freed:               So I know in that same article that we started with it said that you’d done studies to show prevention for humans, also for diseases as Alzheimer’s, cardiovascular disease and cancer. So are there published articles and studies to show that it’s beneficial for those diseases?


Dr. Mark Mattson:     Yeah, the studies show that the intermittent fasting shifts the biomarkers for risk for diabetes, cardiovascular disease and we actually did a study in asthma patients. So for example I mentioned that intermittent fasting increases insulin sensitivity so insulin levels are lowered, fasting glucose levels are lowered in subjects on say the five-two diet – two days a week fasting.

Dr. Krista Varady, a researcher at the University of Illinois at Chicago has focused a lot on people at risk for cardiovascular disease. She published at least half-a-dozen studies showing that lipid profiles are greatly improved, LDL down, HDL up, triglycerides down, and over a period of many months – what she does is much more rigorous there – she has them every other day eat only 500 or 600 calories.

I should point out most all of these human studies have been in subjects who are overweight or obese and there have not, to my knowledge, been studies of people with a body mass index in the normal range or low body mass. Animal studies suggest that the non-overweight subjects may also benefit in various ways from intermittent fasting, but the translational work in normal-weight human subjects hasn’t yet been done.

Click here for part 2.