Dr. Satchin Panda Interview TRANSCRIPT
INTERVIEWER: Hello, everyone. Super excited to be here again with Dr Satchin Panda, who is a professor at the Salk Institute for Biological Science. And this is actually a round two podcast.
Previously Satchin and I had a really long and interesting discussion on his research and how we talked a lot about how the body’s internal clock, which is known as the circadian rhythm, how that is regulated by the external cues, such as light, and how the interaction between light in a certain part of the brain called the suprachiasmatic nucleus. Which is like the master oscillator, as it’s called, or master regulator, of circadian rhythm and how circadian rhythm regulates, you know, when we’re active, when we sleep, when we’re awake, when we eat, things like that.
But also we talked a lot about this other external cue which also regulates circadian rhythm in what’s known as peripheral oscillators. Which are other tissues outside of the nervous system, such as the liver and the gut, and how that’s actually regulated by the timing of the food that we take in. And that’s where Dr Panda’s work comes in, has shed a lot of light on what this — what’s called the timing of the food intake and how restricting that timing of your food intake to a certain period of time, for example 9 to 12 hours during the day, can possibly affect a variety of different metabolic outcomes and health factors.
So his research in animals has shown that animals that are restricted to eating within a 9 to 12-hour window have improved glucose metabolism, improved lipid profiles, improved cholesterol, you know, increased lean muscle mass, decreased fat mass, decreased fatty liver, you know, favorable gene expression patterns, all sorts of, you know, really favorable outcomes.
In addition, he’s also shown that when these mice are fed what would be sort of analogous to, I think, the standard American diet, which is, like, high in sugar, high in saturated fat, just not a really good diet. If they are restricted to this narrow timing, you know, feeding window, which is 9 to 12 hours, they still have improved markers of metabolism and metabolic function. Which is really hopefully in a way because I think it also indicates that there may be some possibility that for people that have a really hard time eating healthy or just don’t eat healthy, maybe even just doing this one thing where they I mean obviously we want them to eat healthy. But if they don’t, eat within a certain time window that’s more restricted possibly that would have favorable outcomes.
So I’m super excited, Dr Panda, or Satchin. So just sort of since we’re talking about this, do we have any human evidence that the people that have, for example, like metabolic syndrome, if they eat within a time-restricted eating window, there’s any benefits to that without changing their food composition?
DR SATCHIN PANDA: Well, historically most of these research studies haven’t looked at timing per se, but there was a very nice, comprehensive review published by American Heart Association that went back to many studies where timing, or at least how many times people ate during the day, was recorded. And after compiling all the studies, it was close to 70 or 80 different studies related to fasting of decent quality, how many times people ate, that found that, yes, limiting food to a certain number of hours during the day or maintaining overnight fasting was beneficial for cardiovascular health. So that’s a very well done meta-review of existing literature.
What we need to do now is to look for new studies where this is specifically looked at where everything else is kept constant and timing is changed so that we’ll see whether the benefit is seen among individuals who already have metabolic syndrome. So that’s what is lacking in the field.
And, as you know, this is a very new area of research and NIH funding cycle is five years, so any of the studies will take at least five to seven years before we see any result and peer-reviewed journals. Particular for, I guess, a clinical trial of actually looking at someone with metabolic syndrome.
Probably obesity, I mean if a person is obese, it may take a little more than just time-restricted eating to lose weight. Although they may, they may lose some. They may require more of a, like, prolonged sort of fasting, but the time-restricted eating certainly would affect their –
INTERVIEWER: I would predict would affect their metabolism.
DR SATCHIN PANDA: Yeah. So what we see in our study, a small study that was published, and also some of the other studies that may be in the pipeline, when people adopt a time-restricted feeding in their regular life, in real life, not in the laboratory condition or in clinical trial, then they naturally reduce their caloric intake without even counting calories.
So, for example, when they stop, suppose their target to stop around 6:00, 7:00, or 8:00 in the evening, then the late night snacks and then the late night glass of wine or beer that used to be their usual habit, they stop that. So in that way they’re doing two things, one is reducing calories and also improving nutrition quality because that extra energy-dense diet is not getting into their system.
So in that way I’m hopeful that we’ll see some weight loss, and then some improvement in real health, blood biomarkers. And in rodent studies what we have seen when we take already fat mice, who have been eating a really unhealthy diet for a long period in their life, and then put them on a time-restricted feeding paradigm, they don’t become, like, lean mice in terms of body weight. They become overweight, not normal.
But surprisingly they’re biochemically or physiologically they’re more healthy because their blood biomarkers for glucose, cholesterol, triglycerides, they come to almost normal range. So we have to make the distinction that some people may not lose a huge amount of weight, but they might actually see benefits in their metabolism and physiology. So that’s one thing you have to look out for.
INTERVIEWER: But this is, the mouse study you were just referring to, they were still fed a poor diet? Isocaloric.
DR SATCHIN PANDA: Yeah, okay. Yeah, they were still fed a poor diet, isocaloric diet.
INTERVIEWER: So imagine if they were fed a better diet and the obese mice were fed a better diet and they were doing time-restricted eating.
DR SATCHIN PANDA: Yeah, so they would be much better. Much better. They would lose more fat mass and become much more healthier.
INTERVIEWER: Can you explain for people who just aren’t very familiar with time-restricted eating or time-restricted feeding, as we call it with animal research, like, just what is that and how does that actually affect your metabolism of glucose and fatty acids and amino acids?
DR SATCHIN PANDA: Yeah, so let’s kind of step back and ask how does it relate to circadian rhythm, or the daily rhythms. So if we think of our daily health, our health, our personal sense of how we feel healthy changes from time to time throughout the day. So, for example, in the morning when we wake up, being healthy means you’re feeling much rested and you’re full of energy to start the new day. You’re feeling actually much lighter, you should not feel that full stomach or grogginess, and have a good bowel movement.
And then throughout the day being healthy means not feeling too hungry, so having some food in your system, and then being productive throughout the day. And then towards the end of the day being healthy actually means having taken a walk or something so you are not feeling really you haven’t moved all day and you’re not feeling that sense of being constrained in a place.