Everything You Need To Know About Intermittent Fasting
Mark Mattson, who has investigated this topic for 30 years, debunks the myths surrounding intermittent fasting as he shares the science behind the benefits and the longevity of this eating pattern.
As usual, a new "diet" has taken over the position of "most popular trend of the moment". How is this one distinguished from the others? Well, it is not a diet, but an eating pattern. Far from finding its validity in the public figures that are making it increasingly popular, intermittent fasting has been studied by experts such as Dr. Mark Mattson, who has conducted studies on the effects of intermittent fasting on neurodegenerative diseases. Yes, you read that well. Finally, an eating pattern that will help us both inside and out!
"Three meals a day and snacks is an abnormal eating pattern when viewed in light of evolutionary history." (Shutterstock)
“A diet indicates what and how much you eat. Intermittent fasting determines how often.”
What is intermittent fasting?
Intermittent fasting is an eating pattern in which a person periodically does not eat any food (or eats a small amount), sufficient to deplete their liver energy stores and to start using fats, which usually takes at least 12 hours.
Intermittent fasting is not a diet; it is an eating pattern. A diet is what you’re eating and how much. Intermittent fasting is how often.What are the benefits of intermittent fasting in the body?
The normal eating pattern for most people in modern societies is three meals spaced out, plus snacks, so the person may never be depleting their liver energy stores (which is glucose, sugar). The liver holds around 600 to 700 calories of energy, and that takes about 10 to 12 hours to deplete. After that, fats are released from fat cells in your body and are converted to ketones, which are the second energy source for cells.Fasting is actually intuitive and natural for the human body, despite the fact that the current eating pattern is so far removed from it.
Three meals a day, plus snacks, is an abnormal eating pattern when viewed in the light of evolutionary history. Prior to agriculture and farming and crops, before the main source of food could be stored and then used whenever wanted, people had to forage or hunt. They didn’t wake up in the morning and have breakfast waiting for them; they had to spend a lot of energy to get food throughout the day. So, undoubtedly, they were depleting their liver stores and using up fat until they did kill another animal and were able to replenish their stores.
From an evolutionary perspective, the evidence suggests that, in the fasted state, individuals whose bodies and brains functioned very well had a survival advantage. They were able to reproduce and pass their genes onto the next generation.
Animals, including humans, are geared to functioning well in a fasted state, and that’s what the animal studies show. Lots of human studies have been done in overweight people, and intermittent fasting can help them lose fat. Other human studies also show that, in a healthy weight, intermittent fasting combined with exercise can enable putting on muscle and reducing fat.Fasting boosts brain power and has a positive effect on neurodegenerative diseases; this is where part of your research lies, in diseases and prevention. How does intermittent fasting bolster brain power?
In the 1990s, we performed a number of experiments where we provided rats or mice into two diet groups: every-other-day fasting and control (which meant that they could eat food all the time). Then we asked the question, “Does intermittent fasting protect nerve cells in the brain against dysfunction and degeneration in experimental models relevant to Alzheimer’s Disease, Parkinson's Disease, and stroke?”
We published many studies in which we found that the nerve cell networks of the animals under intermittent fasting were protected in these experimental models and their functional outcome was better. Their learning and memory was better than the Alzheimer’s model, and their ability to control their body movements was better than the Parkinson’s model.
Then we began looking at what’s happening at the level of the individual neurons, and we came to the conclusion that intermittent fasting enhances the neurons’ ability to resist various types of stress, including exposure to free radicals and reduced energy supply. We also found out that intermittent fasting can stimulate the formation of new synapses between the nerve cells.
The ketones are very interesting from the standpoint of brain aging and Alzheimer’s Disease, because it is well known that, during aging and much more so in Alzheimer’s Disease, nerve cells have a problem using glucose, but they appear to not have a problem using the ketones. So there is a lot of interest now in doing clinical trials of intermittent fasting and people at risk for Alzheimer’s and Parkinson’s.Why do you think fasting is so linked to spirituality and religions? Could it be because it increases our focus? I think that’s very likely. What I would say about religious fasting is that it is probably good for the brain and body health, but, typically, it is not done frequently enough to have a major impact on long-term brain and body health.
Some people would rather either not eat dinner or not eat breakfast. When it comes to the 16/8 fast, do you recommend one set of hours over the other, or are both just as beneficial?
It hasn’t been looked at much in humans, so I cannot say for sure. Both will be better than eating three meals a day and snacks. I’d say that whatever suits people’s schedule or preference is fine. However, it is not good to eat much within a few hours of going to sleep. A lot of people find skipping breakfast the easiest, because then they get up and drink coffee or tea, go to work, and still have lunch and dinner with people.Is there one type of fast you recommend the most, whether the 16/8, the 18/6, the 13/11, or the 5:2?
Well, it seems like it’s easier for people to restrict the time window that they eat each day, versus having two days a week when they eat hardly anything. So the 16/8 or the 18/6 would seem to be the best, based on existing evidence.
One of the key things for people to know is that it takes several weeks, even up to a month, to fully adapt to the new eating schedule, so that they’re no longer hungry during the day. A lot of people will try it one day and say, “I can’t do it”, but if they stick with it for a few weeks, they’ll no longer be hungry during the time that they’d previously been eating.Would you say it is more important to control when we eat, as opposed to what we eat? Or are both equally important?
Both are equally important. People shouldn’t say: “Well, intermittent fasting is good for my health; therefore, I can eat unhealthy food.” That’s not true. They should still eat vegetables, fruits, nuts, some meat (mostly fish and lean meat), whole grains, and a few simple sugars and saturated fats.Why is productivity increased when we fast? Well, once you’re adapted to intermittent fasting, people find that, in the morning hours, they are really alert and can concentrate and have sort of a high perception of their energy levels. They’re also not taking the time to eat breakfast, which is an obvious way they are more productive, given they are spending less time doing that activity.
What has your journey with fasting been like, not just as an investigator or expert, but in your everyday life? How did you begin to practice fasting?
I haven’t eaten breakfast for about 30 years. That was before we did any research on intermittent fasting. When I was in graduate school, I lived about seven miles from the lab, and I would ride my bike there and back each day. I was under some stress and I had problems with gastric reflux.
I found out that, when I was riding my bike there in the morning right after eating breakfast, I’d have a lot more gastric reflux. And then I realized that, if I didn’t eat breakfast, I wouldn’t have much gastric reflux, so I quit eating breakfast. That was what prompted me to start this eating pattern.
The other thing I did later on was to exercise before I ate at lunchtime. There’s evidence that, if you exercise in the fasted state, the beneficial effects are enhanced.When you are in the fasted state, do you only consume water or do you also have black coffee and tea?
Yes, coffee and tea are fine; no calories and, particularly, no carbohydrates.As someone who has been doing this for 30 years, when it comes to the weight element, for those who are already thin and have been fasting for so long that they keep on losing weight, how do you recommend to maintain this eating pattern as a lifestyle without harming other parts of their overall health? How did you find that balance, or did you find it to be easy?
That’s a good question. I found it to be easy until about five months ago, when I had an accident riding my mountain bike and had a bad injury. I lost weight after the two surgeries I needed to have, and I already had a low body weight. During the time when I couldn’t exercise and keep my muscles active, I’d lost muscle mass, but that probably would’ve happened regardless of my eating pattern, because I wouldn’t have been able to regain my muscle mass without exercise.
Both forms of fasting (18/6 and 16/8) will be better than eating three meals a day, plus snacks. (Shutterstock)
Disclaimer:
This interview was originally made in English and then translated to Spanish for Estilos magazine. The original article can be read here, and you can also find it and others in my portfolio. The photos either belong to the magazine and Diario Libre newspaper, or to services they are members of. The version you are currently reading has been expanded for your reading experience.