Episode 17: ‘Fixing’ Metabolism and Optimizing Weight Loss Efforts with Caleb Greer

Evelyne: So, Caleb started his graduate educational journey at Parker University in Dallas, Texas, where he accrued more than 2,000 hours studying and learning manual manipulation techniques. It was during this time that he became immersed in clinical neuroscience and functional medicine. Despite the fondness of physical medicine, after acknowledging the limitations in the chiropractic scope, Caleb decided to pursue a different track to become a nurse practitioner. He graduated with his bachelor’s degree in nursing from the University of Texas at Arlington and a master’s degree in nursing for family nurse practitioner. Caleb has now helped hundreds of individuals across the lifespan reintroduce and optimize function through a multidisciplinary approach that integrates neurology, psychology, epigenetics, nutrition, biomechanics, and medicine. Caleb, in your practice, what do you mainly focus on?

Caleb Greer: Really anything that has to do with taking an individual from any kind of complaint-oriented state of being into something they consider to be optimal in terms of hormonal health, in terms of musculoskeletal health, and ultimately with their pursuit of what makes them feel passionate and how they pursue meaning. So, we look at all spectra of health-related contributions from the outside looking in, but also from the inside out, so emotional health, cognitive health, musculoskeletal, and really biochemical balance.

Evelyne: I know you work a lot with metabolism and weight loss, so I’d love to focus on that today. Would you say you see more men or women, or is it equal?

Caleb Greer: In the weight loss and metabolic side of the practice, it’s primarily women. But, in general, I probably have about equal of both genders.

Evelyne: Okay. So, I’d love to go back to some basics and just establish some definitions for this. What is metabolism? What does that term actually mean in terms of energy sensing and how that couples to the survival of an organism?

Caleb Greer: Yeah, so generally, there’s two concepts that metabolism covers. There’s the level on the cellular basis, which is just respiration, which encompasses the utilization of nutrients and the carbon within, both sugar or carbohydrates and fatty acids, and takes them through the process of catabolism, so using carbohydrates and fatty acids for fuel via the generation of ATP for all cellular currency and work to be done. On the cellular side, that’s what that encompasses, but on a more global perspective, you’ve got the central and peripheral regulators of metabolism, which kind of dictate how much fuel is being expended for a given amount of nutrition that’s stored, either as fat or glycogen, and how that communicates with circadian rhythmicity and other factors that have to do with survival of the organism ultimately.

Evelyne: I’m actually curious about something you mentioned regarding circadian rhythm and how it relates to that. Maybe this is a little premature to ask, but talk about how that relates to metabolism.

Caleb Greer: Sure. The way I explain it to clients and people in general is that the way that our bodies basically convey time of day and how different organs should be activated and how cortisol and glycogen release with glucagon and insulin basically paint a picture of nutrient availability in the daytime, which allows the metabolism to be set up for, based on what fuels available, how much to basically expend for either forging activities or reproductive activities. It gives the brain a perception of nutrient availability within the environment, and then by proxy, safety of the organism in that environment from a basic energy requirements perspective. So, with the genes that orient rhythmicity with clock and period to essentially allow for the parasympathetic nervous system and the sympathetic nervous system to do their jobs in the background after a fundamental assessment of what is available nutrition wise and energy depot wise.

Evelyne: Would you say that because our schedules have gotten so off track from maybe how they used to be that this has a huge impact on this part of metabolism?

Caleb Greer: Yeah, I mean, hypothetically I think that’s a huge part of it. We see it with shift workers. I have quite a few firemen that I see for health-related issues, but one of the biggest problems with their shift work is that their metabolism, their fasting glucose, their insulin dynamics are all shifted in one way or another. So, parsing that out in terms of making sure cortisol and melatonin have an appropriate balance, but also making sure that they’re sleeping well enough and they’re not eating in times of the day that are going to manipulate the energy sensing modalities, but also how their endocrine systems are going to regulate and how essentially that sets them up for poor metabolism the following day of either sleep deprivation or delayed rhythmicity.

Evelyne: Yeah, it’s interesting with firefighters too, because they are exposed to so many more toxicants than the average person, so I’m sure that plays a role. Well, I know that plays a role in their health, as well,. There’s research on this. Since you work with many firefighters and shift workers in general, what are some of the practical things that you do with them to mitigate some of this?

Caleb Greer: Well, from a lifestyle perspective, we do what we can to integrate periods of purposeful food timing. So, not really intermittent fasting or fasting to any degree, but making sure that even if they’re not hungry in the morning when they wake up, especially on their days off, that they’re still consuming a decent amount of macronutrient profile to, again, make sure that their systems, despite what the time period they’re in or what their circadian mismatch might be, that is one quote/unquote “zeitgeber” or “time giver” that allows for them to get around what their sleep schedule might be telling their metabolism. So, at least if there’s a bolus of food at breakfast or in that early period of the day, then that’s one signal that the body’s getting that says, “Oh, it’s actually daytime,” or, “It’s a period where nutrition is available,” and then they will expend their resources accordingly. So, timing of food is a big one, and also making sure that even if they’re getting off late in the day or if they have a call and they’re hungry because they’re awake at night to still avoid consuming calories in those time periods.

Evelyne: That’s challenging, too.

Caleb Greer: It is. One of the biggest things that’s not really in the metabolic window is making sure that their strategies around sleep and making sure that the pillars of making sure the room is super dark, avoiding exposure to blue light as much as they can when they get back to the station. Obviously, they can’t avoid it when they’re on a call, and then also using things like melatonin or other sleep support tools to make sure that they’re going to have as good as an opportunity to reset that circadian rhythm on their days off.

Evelyne: Yeah, absolutely. So, going back to metabolism in general, so you had mentioned nutrient sensing. Can you talk a little bit more about that for aging and longevity, but also for health in general?

Caleb Greer: Sure. I guess I’ll try to reframe that. In terms of nutrient sensing for longevity and health band, it’s a different conversation in terms of what we do explicitly for metabolism. When it comes to nutrient sensing for longevity, manipulating systems like AMPK and mTOR in terms of how nutrients are being signaled for anabolism or for growth is also going to be different depending on age. So, in terms of promoting longevity in an older demographic that might be resistant to protein intake in terms of just their anabolic nature and the loss of testosterone that follows with age, it’s a different approach. It really has more of a nuanced intervention per age and also per goal.

In terms of setting up metabolism by providing amino acids and providing other tools like using Dihydroberberine or something that has AMPK activation to mimic a fasting state, at least from that perspective, is one way to increase metabolism and fuel expenditure via those catabolic processes. But it’s also dependent on what their goal is in terms of building muscle mass or losing fat mass. And so, again depends on what the conversation’s really going to be around.

Evelyne: Something else that you had mentioned was how it’s regulated from the brain and the periphery. Can you explain more about that?

Caleb Greer: Sure. Central regulation of metabolism is really in the forefront, especially now that we have more tools available that have uncovered a lot of the process. So, conditions like Prader-Willi conditions like over obesity in the absence of metabolic syndrome or insulin resistance leads these doors open to say, “Well, if it’s not overconsumption of calories, if it’s not a genetic issue in the brain, what is happening at the cellular level and at the receptor level in the brain to allow for someone to eat past what’s considered healthy, not only for the individual, but for energy expenditure and fuel expenditure for basic cellular functions?”

Evelyne: Are you referring to things like leptin, ghrelin, glucagon? What are you specifically talking about?

Caleb Greer: Yeah, so on the peripheral side, those organs are going to secrete hormones and peptides that basically convey to the brain what’s going on from a nutrient perspective. So, when someone is hungry, that ghrelin’s going to be stimulated from the stomach, and that’s going to circulate the brain and stimulate an increase in appetite so that the animal or the organisms will go and forage for food to remedy that disturbance in homeostasis. So, hunger, being a homeostatic effect, is going to make someone feel like they need to address that need. And so, that need is going to stimulate all kinds of locomotive behavior also coming from the brain to initiate a procedure, a behavior that will ultimately get that need met by i.e., consuming nutrition. So, on the other side of that, whenever someone does have the end result of consuming calories, it’s going to convey as a reduction in ghrelin, which would be more of a satiety metric, but also an increase in these different intestinal peptides that convey to the brain, “Hey, meal termination. Stop eating. We’re good.” And that process is a push and pull throughout the day.

Evelyne: So, in your approach, are you working with that brain signaling or what are some of the tools that you use in your practice?

Caleb Greer: So, one of the easiest, most fundamental ones is just intentionality around meal initiation and meal termination. So, making sure to get a lot of actual chewing in to make sure the digestive process is stimulated well before just consuming something once hunger gets to the point where you’re overruled by it. So, intentionality behind interceptive activity of when hunger starts, having them understand when was their last meal, what is their nutrient capability in terms of their caloric allowances for those days. And obviously, so that the mindfulness around eating and the mindfulness around snacking is one of the biggest tools to convey to someone while they’re in the journey is at least on the non-intervention side. So, mindful eating, making sure that they’re really chewing their food, making sure they’re sitting down while they’re eating and not walking up and kind of mixing up the different behaviors that can also get somewhat bastardized in terms of what it means to truly just supply nutrition to your vessel.

And then, when we get into the intervention side of it, obviously using things to stimulate metabolism from the brain down, and then also to use things like fiber or other ANPK activators to instigate a signal of satiety even if the body wouldn’t necessarily agree that enough calories came in.

So, it’s a fine balance of figuring out what side of the system we need to support. Is it the peripheral side through the GLP-1 class or through something like berberine or the AMPK activators, or is it something that we need to tackle from the central side of it, which is actually just sympathetic output to the fat tissue or upregulation of leptin sensitivity in the brain. So, that’s kind of where each individual is going to get their own plan of action.

Evelyne: Can you tell us what a deviant metabolism would look like? What are the mechanisms that drive that?

Caleb Greer: Sure. So, it gets difficult. So, typically deviation metabolism is going to start with the overconsumption of non-satiating food groups that are very high in calorie, very dense in calories. So, in our day and age, we don’t have many periods of time where we go without. It’s definitely the opposite scenario now where food is in surplus. There’s no activity like hunting or going to forage to actually acquire that nutrition, i.e., we’re not spending anything to actually get our intake. Now, some people might have a different lifestyle where that’s conducive, but for the majority of the population, that’s just not a thing. We can Instacart our groceries to our house. We don’t even have to drive the grocery store and walk around the aisles with our carts.

So, to a large degree the uncoupled nature of where we get our food from and then how much of that food we actually have to consume throughout a season is really where I think most of the metabolic disturbance is going to come from for most people. And then the feedback on the central nervous system in response to that is going to be different based on fructose metabolism and how the downstream mechanisms of satiety and fat storage and energy expenditure are going to be manipulated. But suffice it to say eventually someone will become insulin resistant or leptin resistant or some other process where their body just doesn’t perceive the correct signal. And so, the behavior that manifests secondary to that is just going to be weaker.

Evelyne: Talk a little bit more about changes in fructose metabolism, specifically.

Caleb Greer: The intake of various different carbohydrates, especially if it is in the form of fructose outright or high fructose corn syrup or something else that’s going to manipulate how the carbohydrates are broken down and metabolized to the degree that the fructose is going to be a large stimulator of energy restriction. So, even though the net result is a large amount of caloric intake, the mechanisms within the liver that kind of convey energy restriction because of the way that fructose and metabolism and the over utilization of ATP to break it down, it kind of shows as a caloric restriction. And so, the metabolic outcome of that is to actually reduce metabolism, but increase intake. One of the mechanisms that happens is kind of like a hibernation strategy where the fructose will increase uric acid, and the uric acid will actually feed back and increase the amount of fructose that’s going to be made endogenously.

And that fructose has various different pathways that will increase fatty acid deposition into the liver, but also in other organ tissues as kind of a strategy to hold onto fat for a time period that’s being considered in the future where it’s going to be not a lot of food in the environment. So, high fructose in the environment typically comes from fruit. And so, animals that consumed a lot of this fruit in preparation for a period of fasting or famine because of hibernation, because of winter, had a greater survival mechanism because they had fat stored in the summertime that was also more than they would’ve been able to eat based on the pure satiety perspective. So, being able to overeat because of fructose is an evolutionary conserved mechanism that as human beings, since there is no period of downtime or period of extended fasting, has been turned into a root cause of metabolic dysfunction.

Evelyne: I have a question for you regarding the calories in and calories out. I feel like we’ve gone back and forth with this. It’s not important. It is important. I’d love to hear what your take is, but also what about the effective endocrine disrupting chemicals on all of this?

Caleb Greer: Sure. So, in regard to the calorie in and calorie out equation, it’s still definitely an important foundation to have people understand in terms of sheer energy that’s stored within a certain macromolecule. Now, there’s a lot more nuance when it comes to how those calories are getting broken down because essentially, the energy that you get from the catabolism of one of these compounds is what they’re conveying as the caloric density. But for some things, especially with protein or amino acids or other longer chain polymers of carbohydrate, it’s not the same net outcome in terms of what gets broken down and available for energy. Some of that carbon might be going towards anabolism of other structures which would actually go to the thermogenic effect of those foods. So, when it comes to calories in, calories out, it’s definitely a fundamental part of the equation, but it’s not the end all be all.

And for a lot of people that we see that are overweight or obese, and we do their tracking, which is, in all honesty, typically lower than we would expect for someone who has a weight of a certain caliber. So, if someone is, let’s just say a body fat percentage of 35%, that’s a significant amount of fat that stored as fuel. In order for them to maintain that body weight, it would be expected that they would need to eat quite a bit, otherwise they would lose weight just on the grounds of their body mass.

A lot of women that come in are consuming less than 1,500 calories a day, and that’s somewhat on purpose, but they also just don’t have the hunger to drive them to consume more than that. So, on paper, it would seem that they’re at a deficit for their body mass, but they’re actually still gaining weight or staying the same weight in a way that would kind of obviously prove that that equation is not actually what should be most intervened with. Speaks again more towards focusing on the essential energy expenditure model rather than the peripheral utilization of the actual calories.

Evelyne: I had love to know what are you generally testing in all your patients who come to you specifically to help with weight loss?

Caleb Greer: Sure. So, from the biochemical background, we do a lot with just typical metabolic markers, so looking at fasting insulin, looking at A1C, blood sugar, triglycerides, anything that kind of give us insight on how that energy is actually being seen and how glucose disposal is being handled. The other levels of analysis that we do are just anthropometric, so their body fat percentage, their lean mass percentage, and also their resting metabolic rate by using indirect calorimetry with just breath testing. So, seeing how much energy is being expended for carbohydrate metabolism, for fatty acid metabolism in a fasted state because that will kind of cue us into if someone’s a primary fat oxidizer in their fasted state or if they’re using glucose and carbohydrates for that metabolism when they really shouldn’t be.

Evelyne: I’m curious, what do you think of tools like the lumen device? I see that advertised to me a bit.

Caleb Greer: Yeah, so if you look at how intensive and how much breath is actually required to make an accurate assessment of someone’s metabolism, and I’ve spoken with a few companies that have at-home devices, but it’s still, you’re breathing into it for a solid amount of time before it actually becomes a valid metric of someone’s metabolism. So, I think the one breath and done assessment is probably insufficient to give yourself a really accurate number, but I think directionally it’s appropriate, so if someone’s using that as a day-to-day metric for where they’re at, kind of at a 10,000-foot view, I think it can be helpful. But clinically, I think we need a more validated metric to really make interventions and decisions about someone’s metabolism.

Evelyne: And speaking of at-home devices, do you have your patients also use continuous glucose monitors? Now, are you then analyzing that data?

Caleb Greer: Yeah, so usually it’s when someone looks to be somewhat insulin sensitive, like obviously, if someone is overweight, there’s some level of insulin resistance, but if it’s not showing up either on a glucose tolerance test or in their fasting metrics, there’s something wrong happening at the actual receptor base or the receptor level, not from an actual wide range of things. So, when they use A CGM, we’re looking for deviations in overall glucose, but how high the metric will go before it returns back to baseline and just more area under the curve data that we can get from continuous metrics like the CGM, but also they can test out what foods are doing them the most damage in terms of metabolism and what foods they can utilize to mitigate those spikes, as well. So, objectively speaking, someone has a CGM, we’re expecting it to be off, but it’s more so about what interventions they can do to mitigate those from an intake perspective rather than diagnosing something off of the data.

It’s also really helpful when we start interventions for metabolism or for weight loss in general to see, “Here’s what the data was before we started. Here’s what it was after we intervened with just food choices and time restrictions and so forth. And then, when we started X, Y, and Z supplements or nutraceuticals or pharmaceuticals, how does that actually change on a glucose disposal level?”

Evelyne: Tell me more about some of the interventions that you’re using.

Caleb Greer: Sure. So everything from, again, cognitive behavioral therapies and just intentionality behind food and snacking and this kind of non-intervention interventions, all the way up to using things like semaglutide and tirzepatide and those more powerful movers of central metabolism, even branching into supplementing with thyroid. And again, the balancing of the endocrine system is obviously a forerunner into these systems too, but assuming all that’s regulated and that the thyroid function isn’t needing support, using things like liothyronine, which is just an isolated version of T3 rather than either the glandular extracts or something like levothyroxine. And then, also supporting that with things like iodine and selenium for the actual organ tissue function and making sure that there’s no autoimmunity present or inflammation is going to inhibit the efficacy of the tools that we’re using.

Outside of that, using essential nervous system stimulus to some degree can be effective for someone who’s just reached a plateau or has obvious issues with sympathetic drive to their fat tissues. Sometimes, people’s medication that they’re using for blood pressure or for heart rate issues or for anxiety can also get in the way of someone’s weight loss goals, so redirecting and reformulating someone’s other medical plan can be effective in terms of unblocking some of those pathways. Antidepressants are another big one too, that get in the way.

Evelyne: I have a question about semaglutide, and you mentioned it earlier, you also use tirzepatide, and I actually was not previously aware that Mounjaro has a slightly different mechanism than Wegovy and Ozempic. Is that right? Can you explain, because they’re all GLP-1 agonists, right? Can you explain the differences?

Caleb Greer: Yeah, so Mounjaro has, it’s a dual, what we call a twincretin. So, it has two incretin. It binds both the GIP, the glucose-dependent insulinotropic polypeptide and the GIP-1. It has a dual agonism for both of those receptors. And so, the way that the molecule works, it’s not two different peptides. It’s a single peptide that has activity at both those receptors. How that works to make it more effective, the GIP has more of a energy expenditure at the actual fat tissue, whereas the GIP is going to handle more of the central nervous system activity. So, it is kind of a smart way to get both of those mechanisms activated. The GLP activity of Mounjaro is a little bit less than semaglutide or Ozempic/Wegovy. So, part of the increase in efficacy of Mounjaro actually comes from less receptor internalization from hyperstimulation of the GLP-1 receptor.

In very similar ways that other drugs of high potency will end up recruiting what’s called this β-arrestin pathway. So, once that happens, the cell starts to realize that there’s just too much receptor saturation and that the biological throughput is too high. It will start to internalize some of those receptors to try to balance it out. And so, with something as potent as semaglutide at the receptor, the need to kind of titrate the dose higher and higher becomes more relevant. And that’s also why there’s kind of a ceiling effect on the benefit, whereas with tirzepatide or Mounjaro, I’ve seen that much less and with greater efficacy at lower doses.

Evelyne: Very interesting. Thank you for explaining that. I know you’re a fan of finding nutraceuticals that can sort of mimic the same effect as some of these pharmaceuticals. So, tell us more. With your patients, for example, when are you using medications versus using a nutraceutical approach, and what are some of the things that you are using in your practice to target GLP-1?

Caleb Greer: Sure. So, on the nutraceutical side, I still haven’t found anything that kind of mimics or replaces in any degree what the GLP-1/GIP class of medication can do. Now, from the perspective of nutraceuticals that can help with satiety and increase output to fat tissue, there are several. So, one is called L-BAIBA, and there’s different patents on that particular ingredient that make it standardized. But again, through the pathway of AMPK activation, which is a huge one as far as just the energy expenditure at the cellular level, that’s going to increase the energy output to the fat cells and help, number one, with browning of white tissue, but also just the expenditure of fatty acids and the increase in oxidation is going to happen in those tissues, as well. Another one would be berberine or dihydroberberine, which kind of mimics what Metformin does to some degree. I would actually say to a huge degree with dihydroberberine.

And then, there are others, again looking at the sympathetic nervous system output. So, things like bitter melon is one that increases again through AMPK, but also some of those central mechanisms that increase output from the sympathetic nervous system. Again, from over the counter, using things like caffeine and nicotine, even though there’s some fuzziness around using that as an ergogenic aid. But those things can reduce appetite, and they’re very well known to, and using those in a program to kind of cover more bases and use less of one particular pathway can be super helpful. Also, using things like omega 3 fatty acids and fiber can increase the output from the genetic transcriptions of the regulators of mitochondrial efficiency. Things like using red light and green lights or lasers that have effect on the energy expenditure in cells to increase, again, fatty acid oxidation, more carbon being utilized and breathed off from respiration, and then obviously exercise. Exercise and sleep are two that have a huge impact on what you’re going to be able to expend on a daily basis for all kinds of behaviors of daily living.

Evelyne: When you are recommending exercise to your patients, does it depend on the patient you’re seeing what you might recommend? Does everybody get a recommendation for strength training? What are your thoughts on cardio, strength training, walking?

Caleb Greer: Yeah, so generally speaking depends on their level of fitness. For the population that is excessively overweight or just has issues with pain that come along with the orthopedic disturbances that weight can cause, really just activity in general. So, taking their step count up to 10 or 12,000 steps a day, something that they can do that’s relatively easy that doesn’t require a lot of effort, just carving out time to go and do that. And then, something that I advise all my clients to do as they lose weight is to add on weight in a weight vest or a rucksack that keeps their body, the gravitational forces that they’re used to experiencing, at the same level. So, even if they’re losing weight, they can still carry around the same weight to stimulate the gravitational proprioceptive sensors that relate to bone density and maintenance of muscle mass. So, that’s one technique that I tell everyone to do.

Obviously, on top of that, getting a strength training program that’s conducive to their wellbeing. Obviously, not trying to do anything crazy as far as rep schemes and weight, but comfortably doing as much as they can with more gravity and with more tension on the muscle tissue to generate better strength, especially while they’re losing weight from the fat components and making sure that they maintain their lean mass is a huge factor in someone’s weight loss journey.

Evelyne: I think that getting 10,000 to 12,000 steps a day, you have to really be intentional about that. I know that I need to be active all day plus take an hour walk.

Caleb Greer: It certainly requires intention around someone’s workday, right? So, especially if they live somewhat of a sedentary life or if they work from home. It’s taking calls and moving, right? So, it’s going outside to walk your animals or to take calls or to do as much as you can, even if you have a, what do you call, a stationary pedaler, right? So, if you have a little stationary pedal that you can put under your desk to use just to increase non-exercise related thermogenesis and increasing metabolism in that sense. So, purposeful movement, even fidgeting or something else that requires your respiration to kick up a little bit to where you’re doing three or four more breaths per minute will equate to a greater energetic expenditure and also help to move the metabolism in the right direction.

Evelyne: Yeah. Something we didn’t cover yet when it comes to weight loss, fat loss, is the role of the sex hormones. Can you tell us a little bit more about that, and are you using hormone replacement as well, or again, using nutraceuticals in that department?

Caleb Greer: Sure. So, it’s actually a lot less of a factor in terms of complete energy expenditure. So, testosterone and estrogen probably had the biggest roles to play. So again, making sure that the endocrine system is at least in homeostasis., it doesn’t mean we need to push the hormones from a super physiological level to get what we need, but testosterone being important for lipolysis and for the breakdown of triglycerides and the utilization of fatty acids in muscle tissue, as well as the maintenance of that lean mass, is a huge part of it. But again, it’s not like we have to add in a whole bunch of hormones to get them to their goal in terms of testosterone, estrogen, or even DHA and pregnenolone.

For women that are actively menstruating or having their cycles, it’s about making sure that those cycles are appropriate, that ovulation is occurring, to again, not get in the way of weight loss. But it’s not so much in terms of promoting more weight loss from getting those hormones outside of what they normally do homeostatically.

For women that are menopausal. Obviously getting, again, bringing it back to homeostasis and making sure that those are appropriate throughout their cycle and that we’re doing that in a wise manner is, of course, permissive to better weight loss, but it’s not going to be the only intervention. And I’ve seen it time and time again when we just replace hormones for optimizing the endocrine axis and making sure that hot flashes and sleep and libido and atrophy are all taken care of, that can all happen without an increase in metabolism or a benefit to their weight. So again, it’s permissive, but not necessarily causal.

Evelyne: Thank you for sharing that. Are there any other aspects that you really focus on that we haven’t touched on yet when it comes to fixing someone’s metabolism?

Caleb Greer: So, by and large, again, making sure that the fundamental pillars are taken care of from a nutrient intake, energy expenditure through exercise and non-exercise induced thermogenesis, making sure that their nutrition and diet plans are really dialed in through, again, the RMR testing and kind of looking at their proclivities for fatty acid oxidation and glucose metabolism, and then utilizing different strategies and tactics within the dietary regime. So, whether we’re going to exploit timing interventions or dietary restriction or caloric restriction is going to be an individual conversation with each person, depending on what they’re able to actually utilize and oxidize at a baseline level. I’m trying to think if there’s anything else within the parameters.

Oh, digestion is actually a big one, too. So, looking at the excretion of consumed food, so making sure that someone’s bowel regularity is intact and making sure that we’re not battling with constipation or any kind of backup from the detoxification of things that are going to be released from fat depots.

So, since a lot of the environmental toxins are fat soluble, and that’s where they get stored as someone begins to lose weight, number one, it’s going to alter their estrogen metabolism, but also it’s going to put more stress on hepatocellular detoxification, so making sure that those pathways are also supported and that clients know what things to look out for in terms of backup of their GI so that we can mitigate those as soon as possible.

I always tell people, “You are what you don’t shit.” And so, making sure that all that stuff is going to be removed and appropriately assimilated and digested is a huge factor, and that starts with the stomach acid and digestive enzymes,as well.

Evelyne: Something else you had mentioned to me before was using cold plunges and that hormetic stress. Do you want to touch on that?

Caleb Greer: Yeah. So, we have a cold plunge available for our clients to come and use. It’s one of those things that, for weight loss in general, it’s not going to be widely adopted because it’s not fun, but to the degree that you can use cold stress to increase thermogenesis and increase, again, the sympathetic throughput by means of increasing the catecholamines is definitely going to increase metabolism. If you’re shivering for 10 minutes, I mean, that’s a lot of energy that’s being used to generate heat, and that heat is going to be at the cost of actually using those resources for storage or for other motivated behavior.

So, if you can waste more calories as heat, that’s a good trade-off. A lot of people get out and immediately warn themselves by going in a sauna or drying off and trying to mitigate the shiver, but that’s actually where the magic is going to happen. So, I always tell my clients, warm up by yourself as much as you can. Embrace the feeling of cold, and allow your nervous system to regulate and improve its ability to heat yourself naturally.

Evelyne: That’s interesting because usually we hear that people want to do the contrast.

Caleb Greer: That’s a comfort thing, not a mechanistic…

Evelyne: Huh. Interesting. What are you most excited about in the next few years in medicine? What are the trends you’re looking at? What’s the research you’re exploring?

Caleb Greer: I mean, I think the opening up the avenue with the GLP-1 classes kind of revitalized the obesity research world. And so, I think the next iteration of glucagon and GIP and GLP-1 agonism is going to be huge. There’s already phase two and phase three trials that are nearing completion for a new molecule that it wipes the floor with both in terms of its outcomes to the point that, I mean, I feel comfortable saying that once this gets integrated, if it’s done well from a healthcare utilization perspective, that obesity will at least be cut in half. I mean, if people get access to this tool, it’s going to be substantially impacting the health of the world. So, that’s super exciting.

Then, new mechanisms are getting derived from stimulating muscle growth and metabolism within muscle tissue that’s going to feed back again into the entirety of someone’s metabolism. So, the mechanisms are starting to really be elucidated for why metabolic disturbance happens in the first place and how insulin resistance occurs mainly in the muscle tissue first, and that’s going to pay dividends into how these things are being researched and how we can target them in very refined ways that ultimately get us an improvement in wellbeing from a musculoskeletal and orthopedic side, but also with how it’s going to change our motivation to consume food that is just not good for us. I mean, I think one of the things that we will be seen and what I’m forecasting, if individuals that are consuming fast food and easily attainable calories no longer have a desire or drive to do so, the economics of those industries are going to be significantly impacted. And so, I’m curious to see how that actually translates to the giants of food industry that are going to have to change their schemes.

Evelyne: Yeah, very interesting. And the downstream effects of using these drugs just not just on obesity, but then you’re having effects on cardiovascular disease, blood pressure, all of that, so that’s exciting.

Caleb Greer: Yeah, I was going to say, all the sequela of being obese are going to be things of the past. So the comorbidities of obesity being joint pain and musculoskeletal trauma, essentially, how it’s going to impact the low back pain, how it’s going to impact hypertension, how it’s going to impact the ability to dispose of glucose and not have your world run by food noise. I mean, it’s a substantial change in the wellbeing of these individuals. And to some degree, there’s this ethos from the people that do it naturally in terms of having discipline and having all of their lifestyle behaviors under control, looking at people that use these tools as either cheating in some way or just not having the discipline or some other self-oriented lack of control where it’s the individual that’s the problem and not something genetically or something socioculturally that’s impacting their ability to maintain a healthy body weight. But it’s really, I can’t find an argument to support the lack of use of these tools in terms of the improvement in wellbeing and the reduction of suffering across the world.

Evelyne: Thank you for sharing that. Shifting into some of your personal favorites, what are your top three supplements just for yourself?

Caleb Greer: So, my dailies are really consistent of the baseline. So, kind of say from the background using omega 3s and vitamin D and a good greens powder. Those are just general givens, I think. But for more isolated improvements in a certain domain of function, the cognitive support tools are what I use most frequently. So, I’d say caffeine, Alpha-GPC, and Lion’s Mane would probably be my go-to three that I do on a consistent basis that’s outside of the fundamentals.

Evelyne: Nice. Love Lion’s Mane. And what are your top three health practices that keep you healthy and balanced and supporting your patients day in and day out?

Caleb Greer: Personally, strength training is just one of those that I can’t get away from in terms of the benefits across the board. That could be translated to exercise. It doesn’t have to be strength training, but ultimately, preserving and keeping lean mass high is one of my primary things that I tell all my clients to do. Between cardio and yoga and flexibility work, I mean, that’s all necessary, but the primary, someone has an hour of exercise per week to spend, then it’s going to be with strength training, for sure. The second tool would be sauna. Number one, it’s just so easy, it’s comfortable. It doesn’t take a lot of willpower to go and sit in a hot room or a hot sauna. And the health benefits, again, from a cardiovascular perspective, I think cover a lot of bases for people that either can’t do purposeful exercise or lack the discipline to kind of keep that in a regimen.

So, I would definitely lean on sauna. Now, whether it’s infrared or steam or dry, I mean, I think the Finnish literature is pretty clear, at least in terms of the one that’s most studied, that is going to be the most effective. Now, I don’t know if that’ll hold in terms of where the research is coming, but I feel pretty confident that across the board, if you’re getting your tissues warmer, that the heat shock is going to be beneficial for longevity and health span and all the other benefits. And then the third thing, let’s see. I would say really in terms of mental health, only saying yes to the things that I like to do. So, really setting up personal boundaries for what I do and do not spend my time on, I think is a big one that I’ve developed over the past few years, and it’s made a substantial improvement in my wellbeing, in my mental health. So, I think that’s definitely a health practice that I’ve exploited.

Evelyne: Yeah, thank you. And final question for you, what is something you’ve changed your mind about through your years of practice?

Caleb Greer: Oh, man. So many things. Again, I think the capacity to be able to shift, I wouldn’t even say beliefs, but shift common understandings and perceptions around healthcare practice in general. I mean, it’s a constantly changing field, so actually just not being attached to any one way of thinking or intervention or really anything, but staying humble in the sense that we just don’t know everything and we can’t. So, being able to just go with the flow in terms of where the literature is showing things are effective, where we’re taking evidence bridges and using translational medicine.

I mean, one of the ones that comes to mind most recently is just metformin. And a lot of the literature early on was very conducive to using that as a tool for longevity in healthspan. But I think as it’s become more relevant in the healthcare field, that it is just gotten to this place where it’s just something that we either don’t utilize much anymore, or it has been replaced by much better tools that get the same level of benefit without the potential harms of using metformin. So, that’s definitely one area that I was quite enamored with early on in practice and that I’ve just gotten less and less so given the other tools that are just available.

Evelyne: Yeah, thank you for sharing that. And Caleb, thank you so much for joining us for this conversation today. I really appreciate it.

Caleb Greer: Yeah. No, absolutely. It was a fun discussion. Thanks for having me.

Evelyne: Thank you for tuning in to Conversations for Health. Check out the show notes for resources shared on today’s show. Please share this podcast with your colleagues. Follow, rate, and leave a review wherever you listen. And thank you for designing a well world with us.

Voiceover: This is Conversations for Health with Evelyne Lambrecht, dedicated to engaging discussions with industry experts exploring evidence-based, cutting-edge research and practical tips.