in: Health, Health & Fitness

• Last updated: September 27, 2023

Podcast #391: Micronutrients, Genetics, and Preventing Age-Related Diseases

When you think about diet and nutrition, you probably think about carbs, proteins, and fats. These macronutrients play a huge role in athletic performance and whether you gain or lose weight. But food is also full of micronutrients that are vital for your health and wellbeing. Unfortunately, most people overlook micronutrients, and consequently are deficient in them. My guest today has spent her career researching the ill effects of micronutrient deficiencies and what you can do to optimize them. Her name is Dr. Rhonda Patrick and she’s a biomedical scientist. Today on the show, Rhonda and I discuss micronutrients: what they are, what they do, and why we’re not getting enough of them. 

We then dig into her research into nutritional genomics, or how genes affect how your body processes nutrients. We end our conversation discussing how stressing yourself with cold exposure, heat exposure, and fasting can boost your health. 

Show Highlights

  • What are micronutrients? What are the big ones that play a role in our health and disease prevention?
  • How recommended daily allotments (RDAs) of vitamins and nutrients are set 
  • What percentage of people have micronutrient deficiencies?
  • Can taking multivitamins make up for deficiencies?
  • Can you ever have too much of certain micronutrients? 
  • How micronutrients stave off age-related diseases, including cancers, later in life 
  • How easy it is to keep up healthy amounts of micronutrients 
  • What role do genetics play in our overall nutrition, and how our body processes things?
  • What are hormetic stressors? 
  • The benefits of heat exposure — saunas, hot baths, etc.  
  • The benefits of cold exposure, and the role genetics plays in those benefits 
  • What happens in our body when we fast 
  • What is time-restricted eating? What’s the benefit?

Resources/People/Articles Mentioned in Podcast

Connect With Rhonda 

Rhonda’s website 

Rhonda on Twitter

Rhonda’s podcast

Rhonda on Facebook 

Rhonda on YouTube 

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Brett McKay: Welcome to another edition of The Art of Manliness Podcast. Now, when you think about diet and nutrition, you probably think about carbs, proteins, and fats. These are macronutrients, and they play a huge role in athletic performance and what you gain or lose weight, but food is also full of micronutrients that are vital to your health and well-being. Unfortunately, most modern people overlook micronutrients and, consequently, are deficient in them.

My guest today has spent her career researching the ill effects of micronutrient deficiencies and what you could do to optimize them. Her name is Dr. Rhonda Patrick, and she’s a biomedical science. Today on the show, Rhonda and I discuss micronutrients, what they are, what they do, and why we’re not getting enough of them. We then dig into a research into nutritional genomics or how genetics affects how your body processes nutrition. We end our conversation discussing how stressing yourself with cold exposure, heat exposure, and fasting can boost your health.

After the show’s over, check out the show notes at Dr. Patrick joins me now via Skype.

Dr. Rhonda Patrick, welcome to the show.

Rhonda Patrick: Thank you.

Brett McKay: Tell us a bit about your background and your area focus when it comes to health, diet, nutrition, genetics, et cetera.

Rhonda Patrick: I have a PhD in biomedical science. I have done research on aging. I’ve done research on metabolism, cancer metabolism, and I’ve done research on micronutrients, which are about 30-40 essential vitamins, minerals that we must get from our diet because they’re essential for life, and how micronutrients are really important for health and for preventing certain biomarkers for age-related diseases. I’ve kind of done a broad range of research, everything from metabolism to cancer to just looking at the aging process itself.

Brett McKay: You’ve also tapped into looking into genetics as well, how genetics interacts with all these things.

Rhonda Patrick: Right. The field’s called nutrigenomics. That area of research of mine is not something I’ve actually published on but is an interest that I’ve just researched because I’m very interested in that field for selfish reasons and just because it’s a fascinating field how people are, respond differently to different types of diets, to different macronutrients and micronutrients, and things like that.

Brett McKay: Let’s talk about micronutrients. We’ve had guest nutritionists on the show just to discuss macronutrients: carbs, fats, protein. Your focus, as you said, is micronutrient deficiencies and the roles and age-related diseases. You mentioned micronutrients, there’s 30 of them. What are they, and what are some of the big ones that play a big role on our health and possibly disease prevention.

Rhonda Patrick: Well, 30-40, somewhere around there, and they are essential vitamins and minerals like magnesium, vitamin C, vitamin K, things like that. We have to get them from our diet because without them, you die. Recommended daily allowances have been set for these vitamins and minerals to ensure that we get adequate amounts of them, but the way the RDA is set is that studies are done in animals were animals are made deficient of a certain micronutrient, so for example, a B vitamin. Once the deficiency level causes an animal to die, the RDA set a couple of standard deviations above that.

Essentially, the RDAs are just to maintain normal health just to make sure that people don’t have such a deficiency that they get sick and die. That’s important to understand because we don’t really know what levels are needed to prevent and stave off, for example, diseases of aging, but with that said, there’s a variety of micronutrients that are really important for disease prevention. For example, magnesium. Magnesium is an important mineral. It’s actually found at the, it’s at the center of a chlorophyll molecule, and chlorophyll’s what give plants their green color. Magnesium is found in plants, leafy green plants, and it’s a co-factor for enzymes, which means, basically, enzymes in your body are what are running your metabolism. They’re running a variety of processes, and these enzymes require certain co-factors, which are vitamins and minerals, to make sure they run properly.

Magnesium’s required for co-factor that repairs damage to DNA. DNA damage actually is a precursor to mutations that can lead to cancer, to mutations that just accelerate the aging process in general. When you don’t get enough magnesium, you start to get more and more DNA damage, and as decades pass on, you eventually can acquire more mutations that lead to cancer.

That’s just one example. Folate’s another one. Folate’s also found in dark, leafy green vegetables. Folate’s required every time you’re going to make a new cell, you have to make new DNA. Well, you need folate to make a precursor to make new DNA. Every time you’re going to make a new cell in your liver or your kidney or your heart or your brain, you need folate. It’s been shown, actually, that if you have deficiency in folate, it can be similar to actually standing underneath ionizing radiation in that it damages your DNA because you don’t have that precursor that you need to make it. Your body does this weird thing where it incorporates something else it’s not supposed to be there, and it causes damage. That’s another example.

There’s other examples. Omega-3 fatty acids are really important. Studies have shown that people with the highest omega-3 fatty acid intake have like a 9% reduced all-cause mortality, which means they’re 9% less likely to die early from cardiovascular disease or cancer, Alzheimer’s disease or Parkinson’s disease. Those are some examples of important micronutrients for health.

Vitamin D is also another one, but vitamin D is not something that’s typically consumed from diet. It’s actually made from UVB radiation when the sun hits our skin, but the problem is a lot of people now are wearing sunscreens, which blocks UVB radiation, which means you don’t make vitamin D when you’re in the sun. Also, just being indoors a lot, people are in their offices and their cubicles, they’re at their computer screens, spend less time outside, so vitamin D deficiency has become a little more common than it was a few decades ago when people spent a lot more time outside. Vitamin D’s extremely important for a lot of processes. In fact, about 5% of the human genome is regulated by vitamin D, which actually gets converted into a steroid hormone. It’s not just a vitamin. It actually gets converted into a hormone inside the body. That’s another example of a really important micronutrient.

Brett McKay: You’re talking about deficiencies. It micronutrient deficiency a problem in our modern age, or are certain segments of the population more susceptible to micronutrient deficiencies because most food is fortified and things like, or most processed foods.

Rhonda Patrick: Right. Actually, I mentioned RDAs, and there’s a lot of nutritional health and examination surveys that have been done that have found, for example, in United States, at least, about 70% of the population does not have adequate levels of vitamin D, about 60% of the US population does not have adequate levels of vitamin E. Vitamin E’s found in foods like nuts, avocados, olives, olive oil. About 45% of the US population has inadequate levels of magnesium. Again, magnesium’s in dark leafy greens. 35% of the population has inadequate levels of Vitamin K. Vitamin K is also found in dark leafy greens. Vitamin A, so 34% of the US population does not have adequate levels of vitamin A.

You get the point. There are these inadequacies, which are not quite deficiency. I mean, when you get to real deficiency, you can start to have acute health problems crop up, but inadequacies still means you’re not getting an adequate level of the vitamin or the mineral. We do know that that is the case in the United States, which really means people are not eating enough of their leafy greens, they’re not eating enough of the healthy foods, healthy nuts and avocados and things like that. We do know that people that are overweight and obese tend to be the most deficient, have the most micronutrient inadequacies because those people that are obese and overweight also tend to eat a diet that is micronutrient-poor and more rich in refined carbohydrates and refined sugars and processed foods and things that may have a lot of calories or may have a lot of sugar and fat but don’t necessarily have a lot of micronutrients.

Brett McKay: I was going to say, couldn’t you just take a multivitamin to make the deficiency, or is that not adequate enough.

Rhonda Patrick: Taking a multivitamin may help serve as like an insurance to make sure that you’re at least … It certainly has been shown in studies that people that are deficient that take a multivitamin, they can bring their levels up to more adequate level in some cases, or at least better than they were, but of course, it’s best if you can eat a varied diet, a diet that’s rich in a variety of different vegetables and fruits because those are very good sources of micronutrients. Also, fish is a great source of omega-3 fatty acids. But a multivitamin, I don’t know if it would solve the problem, but it certain does seem to help, at least according to some studies that have been done.

Brett McKay: We’re talking a lot about we need adequate micronutrient consumption to stave off certain diseases, but we’re living in an age where everyone wants to optimize, optimize everything. Let’s say someone is on top of their micronutrient game. They’re getting out in the sun. They’re taking magnesium. They’re drinking green smoothies, whatever, every day. Is that going to provide any benefit? Is there such thing as too much of a good thing, or is it diminishing returns as you consume more micronutrient.

Rhonda Patrick: It definitely depends on the micronutrient we’re talking about if you’re talking about too much of a good thing. Some of the fat soluble vitamins like vitamin D, vitamin A, you can get too much of those, and that’s certainly something to be aware of. I mean, you don’t want to megadose or overdose on some of these vitamins like vitamin D or vitamin A, but the question is, how much of these micronutrients do we need to stave off age-related diseases. As I mentioned, the way these RDAs are set, they’re set on preventing animals from dying and going a couple stand deviations above that and saying, “Well, that’s how much we need to make sure humans aren’t going to get sick and die from a deficiency in a certain micronutrient,” but what we don’t know is, well, how much are these micronutrients like magnesium are needed to prevent DNA damage?

A lot of metabolic pathways require micronutrient, but some of these metabolic pathways are essential for short-term survival. For example, I’ve already mentioned magnesium. Magnesium’s required to make and utilize energy. That means without magnesium, you can’t make energy. Essentially, if you can’t make energy, you’re eventually going to die. That’s a really important metabolic process that requires magnesium, but magnesium’s also required to repair DNA damage. Well, DNA damage isn’t going to have any effect on your short-term health. I mean, you can acquire a lot of DNA damage, and it’s not going to matter until about 30, 40, 50 years later when you start to then get mutations that can lead to cancer.

My former postdoctoral mentor Dr. Bruce Ames actually proposed a theory, which she calls Triage Theory, where those metabolic processes that are required for short-term survival will get their share of the micronutrient first because nature wants you to survive long enough to reproduce and pass on your genes, whereas the processes that are more concerned with long-term maintenance, process involved in mitigating aging in the long-term, they ultimately get neglected. It’s like a strategic rationing of micronutrients, and it’s helpful to think about how the body may deal with micronutrient inadequacies. He’s actually published a couple of theoretical studies backing this idea, but the reality is, is that we don’t really, really know. We don’t have enough empirical evidence to say the RDAs are enough to prevent aging, they’re enough to prevent DNA damage or prevent calcification of the arteries or to prevent this type of insidious damage that leads to age-related diseases.

I think that the best thing someone can do is at least make sure they’re trying to, for sure, meet the RDAs, which, as I mentioned, a large proportion of the US population’s not even doing that, but in addition to that, making sure you’re getting a nice, broad spectrum of whole foods, variety of colors and vegetables, and a variety of fruits and healthy meats and things like that, I think, are probably your best bet.

Brett McKay: Right. You don’t have to do anything crazy. I mean, that’s what’s so funny about health advice. It always goes like, “Eat good food, sleep well, and exercise,” and that’s all you have to do. I mean, kind of the bare minimum, and you’ll be okay.

Rhonda Patrick: Yeah, it’s pretty much, I mean, that’s like the safe thing that we can do right now, I mean, until we have more evidence as to what else can we do.

Brett McKay: Right. You mentioned earlier you do, is that nutrigenomics. This is sort of your passion project, and you’ve got tools on your website, FoundMyFitness, where people can upload their DNA, basically, and you can see how your body might respond to different micronutrients. What role do genetics play in how our body uses both micronutrients but even macronutrients.

Rhonda Patrick: It plays a really important role. The whole idea behind nutrigenomics, which is this interaction between genes and diet, is that throughout human history, a diet has been really dictated by where we lived, so according to geography. When you live in a part of the pre-industrialized world, you only had certain foods that were available to you. The foods that were available to you had very different composition, different micronutrient because the soils are different, so different plants are taking up different micronutrient differently. Also, different macronutrients. Some people had access to more animal products, some people had less access to animal products.

With a given region, it’s reasonable to expect that over time, over multiple generations, people began to adapt, to tolerate very different nutrient thresholds, both micronutrients and also macronutrients. That’s sort of the theory behind the nutrigenomics, but to get to your question, specifically, what role does it play in, for example, the metabolism of micronutrients or macronutrients, we know that there’s a variety of variations in genes that regulate both of these things.

For example, one of the probably most well-established findings in this area is how your body responds to saturated fat and, in turn, how that affects your cholesterol levels. There’s a gene called APOE that’s very important for recycling cholesterol. About 25% of the population has a version of it called APOE4 that can predispose them to very, very high LDL cholesterol levels. People with this version of it have a really high risk for heart disease, and they also have a really high risk for Alzheimer’s disease. That’s probably one of the best-established genes that regulates cholesterol levels.

I actually became interested in this field because I found out that I had one version of the APOE4, and so I had to really tailor my saturated fat intake because saturated fat, which is found in foods like dairy products, butter, very fatty cuts of meats like pork, and so I found out I had one of those copies, and I had to tailor my diet to lower the amount of saturated fat I was taking in. That really did change my LDL levels.

Another really well-established nutrigenomic finding in this area is the omega-3. There’s three different versions of omega-3. One of them is a plant version. The plant version, called alpha-linolenic acid, can be converted into eicosapentaenoic acid, which is usually found in fish, which then can be converted into the other form, docosahexaenoic acid, DHA, which is also found in fish.

It turns out that the gene that converts alpha-linolenic, also called ALA, into EPA, there’s variations in it. Some people do it very poorly. For example, they can do it 30% less efficiently. If some people, for example, that are vegetarians, it’s actually really important for vegetarians because vegetarians are relying solely on their source of omega-3 from plants, which are flaxseeds, chia seeds, microalgae oil. Those are great sources of omega-3, but these people that are not converting it very well into EPA and DHA have to really know that because then they really can’t rely on flaxseed or chia seed. They have to rely more microalgae oil because the microalgae oil already has it in the form of DHA. That’s another one.

Vitamin D is another one that’s also regulated. Some people don’t convert vitamin D3 into the steroid hormone very well, the active form of vitamin D. Those people, actually, if they’re supplementing, they have to take an even higher dose than other people that don’t have that variation would. I think those are some of the probably best-established findings in that area.

Brett McKay: Yeah. No, I have the vitamin D thing, like I don’t convert it as well.

Rhonda Patrick: Ah. Have you had your vitamin D levels measured?

Brett McKay: No. I just did. I haven’t gotten the results yet from my doctor. My mom has done that, gotten the vitamin D, and she’s been found deficient even though she was taking a vitamin D supplement, so she actually had to increase her vitamin D. I’m imagining that there is an issue there of genetics.

Rhonda Patrick: Yeah. I’ve had a few friends that have also had that issue where they were taking vitamin D supplements, and even quite large doses, and still, that wasn’t moving the needle in terms of raising their blood levels of vitamin D.

By the way, really adequate levels of vitamin D are considered to be between 40 and 50 nanograms per milliliter because that’s associated with the lowest all-cause mortality within, there’s like 33 different studies that have been analyzed that have found that. Typically, when people take a vitamin D supplement, generally speaking, if you don’t have the variation that we were talking about, generally, 1,000 IUs of vitamin D will raise blood levels by 5 nanograms per milliliter. Now, people with that certain variation, that’s not the case, and they actually may have to take more, but the only way to know that is to get a blood test and also look at your genes as well. Doing both is really important.

Brett McKay: I also used your tool, and I also found that I think I have the saturated fat thing where it increases LDL, so I have to watch out for saturated fat, and that consuming high levels of fat will make me obese, which is interesting because everyone talks about … I’ve tried the paleo or no-carb diet, and I always got fat and tired doing it. It was frustrating because it’s like, “Well, look at all these guys online. They’re just shredding body fat. I’m just tired and fat.”

Rhonda Patrick: Yeah. That’s interesting. You probably had … There’s a variety of different genes that regulate the way your body metabolizes saturated fat, and FTO is one gene. Another one is the PPAR-alpha and gamma. For people who have a certain variation of that gene, if they have a high saturated fat and low polyunsaturated fat and monounsaturated fat intake, they can have increased obesity risk, they can have increased LDL levels, increased triglycerides, and even increased insulin, problems with insulins and blood glucose levels.

There’s a study that was published a couple of years that was a really well-done study in this field nutrigenomics, that came out of the Weizmann Institute in Israel. The study basically took 800 people and put continuous glucose monitors on them, which measure blood glucose levels every five minutes. They gave these people then a variety of different diets. They gave them either a high-fat diet or a high-carbohydrate diet that were more vegetable kind of carbohydrates, and then a high refined carbohydrate diet.

What the study found was that people had various responses in terms of their high blood glucose depending on their genetics and also their gut microbiome composition, but so it wasn’t like some people were given the fat, and their blood glucose levels shot up, even though fat is very low on the glycemic index because it doesn’t have glucose. You’d think, “Well, your blood glucose level shouldn’t rise.” Well, some people, their blood glucose levels rose really high when they ate dietary fat, and that’s because they had certain variations in genes that regulate the way their body processes fat. That does make a difference.

I think it is really important to keep in mind any time anyone’s doing any type of experimental diet. They should always measure something. Before you start the diet, get a lipid panel, so look at your LDL, your HDL, your triglycerides. Also, measure blood glucose levels before you start the diet and then after you start it so that you can see whether or not this diet’s changing your various biomarkers of health in a good or bad way. If you see things are going in a bad direction, you can then also look at your genetics to understand why, possibly.

Brett McKay: Besides things on diet and nutrition, you’ve also done some research and writing on things that are called hormetic, is that the right word, hormetic stressors?

Rhonda Patrick: Uh-huh (affirmative).

Brett McKay: What are hormetic stressors?

Rhonda Patrick: Well, the concept of hormesis refers to exposing the body to small amounts of stress, which then triggers cellular responses in the body that exceed what is actually needed to compensate for that little bit of stress that you expose your body to. There’s actually a net-positive effective, meaning some of the cellular pathways that get activated are antiinflammatory pathways, antioxidant pathways, genes that are important for clearing away damaged cells, genes that activate stem cells.

Hormetic stressor is often referred to as like a good type of stress, and it can include activities like exercise; heat stress, for example, using a sauna or a hot bath or a steam shower; cold stress, so using like a cold shower or even an ice bath; and even polyphenols found in a variety of plants are referred to as hormetic stressors.

Brett McKay: Let’s talk about the heat stress. I’ve read some of the things you put out there about that. What are the benefits of exposing yourself to heat via sauna or steam bath or hot bath?

Rhonda Patrick: Well, a lot of the benefits from the sauna are based off of research from a Dr. Jari Laukkanen who is out of Finland and has done some studies on large number of participants, about 2,000 men that have used this sauna either 2-3 times a week or 4-7 times a week or just one time a week.

What he’s found and published multiple studies on is that men that used the sauna 2-3 times a week have a 27% lower cardiovascular disease risk, 24% lower all-cause mortality risk, 20 lower percent Alzheimer’s disease risk compared to men that only use the sauna one time a week, but when you go up to 4-7 times a week, it’s even more robust. For example, those men have a 50% lower cardiovascular disease risk, 40% lower all-cause mortality, and a 66% lower risk for dementia and Alzheimer’s disease compared to men that use it one time a week. There’s a variety of different mechanisms that also been looked at.

For example, Jari has looked at how heat changes the blood vessels and how basically your blood vessels become more pliable and respond better. It increases plasma flow and basically takes a lot of workload off your heart, so basically, every time your heart beats to pump blood throughout the body to make sure blood gets to your various organs including your brain, it has to do less work, so it lowers what’s called cardiovascular strain.

There’s a lot of studies looking at what are called heat shock proteins, which are activated when your body is exposed to heat. Heat shock proteins have been shown to prevent proteins from forming aggregates and plaques in your arteries and also in your brain, which leads to Alzheimer’s disease. A variety of studies have been done on that and have shown that people that sit in the sauna that is at least 160 degrees fahrenheit for about 30 minutes, they can activate their heat shock proteins by about 50%, and this lasts for about two days without having to get back into heat stress, but if you think about it, exercise is also a form of exercise. When you do exercise, you’re elevating your core body temperature.

In a lot of ways, doing something like a sauna or a steam shower or sitting in a hot bath, it elevates your heart rate to somewhat moderate intensity exercise level. A lot of the cardiovascular exercise benefits can be had from doing something like sitting in the sauna for 20 minutes or so. That’s work that, like I said, a lot of it’s coming out of Finland.

Interestingly, because we’ve been talking about genes, there are variations in genes that actually increase the activation of heat shock proteins in people, and, very interestingly, people with these certain variations are more likely to live to be a hundred.

Brett McKay: Huh. Interesting. Well, let’s talk about the opposite, cold exposure. We have guest on talk … Scott Carney, he wrote a book about Wim Hof cold exposure, but what role … I mean, we know the benefits. There’s a lot of them, but what role do genetics play in whether you get those benefits from cold exposure?

Rhonda Patrick: It depends on the benefits. I would say the two main benefits, or the most robust, I think I would say, most profound physiological responses to cold exposure is one the robust release of norepinephrine from a part of your brain called the locus coeruleus region. Norepinephrine’s really important for focus and attention, vigilance. It also improves mood. That’s one robust, I would say, physiological response to cold. In fact, even people that immerse themselves in 40 degree fahrenheit cold water for just 20 seconds could increase their norepinephrine by two to threefold, so 200-300% over their baseline, which is pretty good.

The other response to cold is the increase in mitochondrial biogenesis, which is basically means you’re growing and generating new mitochondria, which are the powerhouse, energy-producing powerhouses of the cell. This has been shown to happen in adipose tissue and also in muscle tissue. This is a really great thing because, essentially, what’s happening is you’re replacing old damaged mitochondria with new healthy young mitochondria, and also, when you’re making energy, you’re releasing heat as a byproduct, so it’s actually part of the way your body stays warm. It’s part of the reason why you actually do make more mitochondria when you’re exposing yourself to the cold.

Genetics does affect one of the processes of ramping up your energy metabolism through a process of just basically taking your mitochondria and uncoupling them. The gene that does this called UCP1. There’s different variations in this gene. Some people have a variation where they do it really well, and so they can actually tolerate cold even better than people that don’t have that variation of it because they’re able to ramp up their metabolism even more, generate more heat to stay warm and so they can stay in colder temperatures for longer. They also have the benefit of burning more fat when they’re in the cold. Those people are lucky in that regard.

Brett McKay: Is this the brown fat, white fat thing?

Rhonda Patrick: Yeah. It is. Exactly. The reason why it’s called brown fat is because when you make more mitochondria, so I refer to this is called mitochondria biogenesis, and you look at a fat droplet under a microscope, the more mitochondria, they look darker in color. That’s why it’s often referred to as brown fat. It’s essentially just because you have more mitochondria in the fat tissue, in the adipose tissue. That’s why it’s called brown fat.

Brett McKay: Yeah. Using the tool, I found out that I don’t make brown fat, or that doesn’t happen to me. I won’t lose weight if I take cold showers. I won’t lose fat.

Rhonda Patrick: So you don’t that as well.

Brett McKay: I don’t do it as well. Right. I don’t do it as well. But I still do it because, I mean, it feels good. I mean, that’s why I like-

Rhonda Patrick: Norepinephrine-

Brett McKay: … to do it.

Rhonda Patrick: … response. Yeah. I actually do it, I like taking a cold shower before a big event or if I’m going to give a talk or something that usually gives me a little bit of anxiety. I’ll take a really cold shower for as long as I can, and I really find that it helps lower my anxiety and helps me focus and just stay focused for longer and feel good. I like the cold showers, definitely. I’m a big sauna fan, but I really like the cold showers.

Brett McKay: Fasting. Is that a hormetic stressors as well?

Rhonda Patrick: Fasting is also, yeah. Fasting is another hormetic stressor. In fact, a lot of the benefits of more prolonged fast, which are longer fast, 3-5 days in humans, a lot of that research has been done by Dr. Valter Longo at USC. He has shown, he’s done studies in both animals and humans, and he has shown in animals studies that basically a prolonged fast causes whole organs to shrink during the fast and then literally regrow after the fast, which is quite phenomenal if you think about, like your liver just shrinking, and also, it happens other organs as well, and even parts of the brain.

He’s showing these organs are shrinking and regrowing, and what he’s found is that what ends up happening is that the fasting is a stress that causes any cells that are damaged that already have, that are not healthy cells, they’re more damaged, those cells die by a process called apoptosis. Then this happens during the fast because the fast is such a strong stress, it causes those damaged cells to die, but the non-damaged cells, the cells that are healthier, it increases all these stress response pathways in them so they make more antioxidants, more antiinflammatory molecules. They just become more robust and stronger, and the damaged cells that die, what ends up happening is it causes stem cells to become activated. During the re-feeding phase, so after you’re doing fasting and you start to eat again, the stem cells start to make new cells to replenish whatever cells were lost. That’s where the shrinking and then regrowing of organs comes from.

It also, you have better metabolism and things like that, but I find the clearing away of damaged cells and then essentially replenishing them with healthy new cells, I find that to be a very interesting area of research, and also, it has lots and lots of implications for many diseases as well as just aging in general.

Brett McKay: Yeah, I think I’ve seen studies where reduced calories can increase longevity. In mice, at least they’ve seen that.

Rhonda Patrick: Right. This is another way of doing, instead of having a reduced calories all the time, you just do this three or four-day fast every so often, depending on what your health status is. Some people that are really unhealthy and obese may have to do that more often than others that are not that are already healthy, maybe doing it once a quarter or something like that may be a nice way to clear away all the damaged cells. It’s kind of like taking out the garbage, getting rid of the bad stuff and replenishing it with new healthy cells.

Brett McKay: Does the fast have to be 3-4 days to get the benefits? I mean, I mean, is there a benefit for fasting 16 hours or 24 hours?

Rhonda Patrick: Well, in terms of the stem cell activation, clearing away the damaged cells, Valter has shown that the prolonged fast, so the three, four, five days is important, but he also has what’s called fasting mimicking diet, which is a five-day diet, and it’s a low calorie, and it has a certain macronutrient composition. You can only get a certain amount of your calories from fat, a certain amount from carbohydrates, and a certain amount from protein.

He’s shown that in a lot of ways, that could mimic a water fast. That’s a lot of work that he’s done, but, yeah, there are a lot of benefits from doing just a 14, 16, 24-hour intermittent fast as well. I actually practice something called time-restricted eating, where I eat all of my food within, I try to eat it within a 10-hour time window so that I’m fasting for 14 hours every night. You’re getting this 14-hour intermittent fast on a daily basis.

Studies have shown, and this is a lot of work that’s been done by Dr. Satchin Panda at the Salk Institute, and that has shown to really improve metabolism in general, just to make, your metabolism runs better. That’s something definitely I would say a lot of benefits, but you’re not going to be getting the robust clearing away of damaged cells and regeneration from just doing a short fast like that, but there are benefits just for normal metabolism. That’s important. I think that, I personally think both. I’d like to start doing a little bit more of the more prolonged fast.

I think Dr. Valter Longo’s fasting mimicking diet’s nice because a lot of people don’t want to do a water fast. It’s a really hard stressor, and it’s kind of daunting to some people to not eat for three or four days. The fasting mimicking diet, which essentially is, like I said, there’s a calorie cap. It’s about 750 calories a day, and 44% of those calories from fat, 47% come from carbohydrate, and about 9% come from protein. He’s got this whole diet that mimics that water fast and basically activates a lot of the same cellular pathways and have a lot of the same responses. At least that’s what his preliminary data has shown.

Brett McKay: Right. That’s not for the faint of heart then.

Rhonda Patrick: Yeah.

Brett McKay: Because I was thinking, as a parent, man, that, or you’re a working parent, 3-5 days without food, I think I’m already … You can go bonkers with that.

Rhonda Patrick: Right. Yeah. Yeah. I think the fasting mimicking diet seems like a lot, definitely going to be more compliant where it’ll be a lot easier for people. I know a lot of people that have done it. I haven’t done it yet just because when I started to get into this, I got pregnant, and now I’m at the point where I’m breastfeeding, so I’m not like, I don’t want to do any sort of fasting crazy stuff until I’m done with that whole process, but I am interested in trying it out soon. I’m definitely going to try that out.

Brett McKay: Well, Rhonda, this has been a great conversation. We literally scratched the surface of what you’ve written about. Where can people go to learn more about your work?

Rhonda Patrick: Certainly they can go to my website, which is FoundMyFitness, all one word. No spaces. I also have an iTunes podcast, which you can find by searching my name or also by just searching FoundMyFitness, all one word. I’m also FoundMyFitness on all social media platforms: Twitter, Facebook, Instagram.

Brett McKay: Awesome. Well, Dr. Rhonda Patrick, thank you so much for your time. It’s been a pleasure.

Rhonda Patrick: Thank you.

Brett McKay: Like I said, Dr. Rhonda Patrick, she’s the founder and owner of FoundMyFitness. You can find that at where you can find all the episodes of her podcast as well as take that genetic test we were talking about to see how your body interacts with different nutrients. Also, check out our show notes at where you can find links to resources where you can delve deeper into this topic.

Well, that wraps up another edition of The Art of Manliness Podcast. For more manly tips and advice, make sure to check out The Art of Manliness website at, and if you enjoy the show, please give this review on iTunes or Stitcher. It helps out a lot. If you’ve done that already, please consider telling a friend or family member about the show if you think they’d get something out of it.

As always, thank you for your continued support, and until next time, this is Brett McKay telling you to stay manly.

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