Science to Transform Series: Caloric Restriction for Weight Loss (Part One of Four)

Are you curious about how calorie restriction works? Don't miss out on part one of this four-part series.

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Crystal O'Keefe: Welcome to the MetPro Method Podcast. I am your host, Crystal O'Keefe. Today I am joined by MetPro founder Angelo Poli and Angelo, thank you so much for being here today.

Angelo Poli: Thank you for having me, Crystal. Always a blast.

Crystal O'Keefe: It is, and I am excited because we are kicking off, a special mini-series of the podcast.

MetPro just recently finished up some amazing research that we wanted to share with all of our listeners. So we're gonna spend a little time in explaining the idea behind the research. And when I say we, I mean Angelo.

Angelo Poli: You're no slouch yourself. You know a lot of this stuff, as well Crystal.

Crystal O'Keefe: I do, but I like to put all the work on you. We're gonna dive a little bit deeper into the first main section being calorie restriction. So, Angelo? With that, can you give kind of a high-level overview of how this research was conducted and why?

Angelo Poli: So, this is actually something that's really near and dear to my heart and really getting back to the roots of what we do at MetPro, what we are, and research and best practices. I'm a science nerd. This is what we've always liked doing. What drives me is answering the question of why and what's optimal.

You know, originally, we started with very high-level programs, very nuanced programs for elite athletes, and that's just evolved. And of course now just as important as the behavioral component. But this research project allowed us to kind of go back to our roots and dive back into looking at a spread of some of the best research that's been done in the last 10 to 15 years on all topics having to do with, what we have.

Essentially identified as the grandfather modalities as it relates to affecting our metabolism, our body composition, and weight. And so instead of looking at a hybrid approach on its own, what we've decided to do is break down the research into four quadrants, the effects of calorie restriction because that's probably the most well-known, most well-researched.

Although many of these are well-researched, so we can actually dive into it and answer the question, what does the research say about straight calorie restriction? Then we'll compare that against carbohydrates' effect on body composition.

Crystal O'Keefe: Yeah, there's a lot of noise out there about carbohydrate restriction.

Angelo Poli: There is, and this is another area where we don't have to guess. We have a plethora of research that's been done, so we can actually look at the bulk of research and draw some conclusions, and even compare the impact of calorie restriction versus carbohydrate restriction, and what lessons we learn from that.

So if that interests you, stay tuned for the next episode, because that's what we'll dive into that one. And then we're gonna look at the third staple, and that's exercise impact. So this is not necessarily debated, everyone knows exercise is important, but what we're gonna answer is how important and what it will and won't do in a fat loss, weight loss scenario, and we're gonna just get to the bottom of it. And then finally, for our last episode, we'll cover the research that we've found on nutritional periodization, metabolic adaption, and body composition.

And that's gonna be the nerdiest of all the four categories. And you're like, well, what's that? Well, you've heard of it before. That's basically when, over time, you are eating differently. Increasing and decreasing intake. Increasing or decreasing carbs, intermittent fasting, or cyclical fasting.

Anything like that. Performance cycles of bulking stripping. All of that falls under the category of nutritional periodization. So we're gonna get to see the math and all the science and nuance relating to that and how that stacks up against the rest.

Crystal O'Keefe: Oh, I can't wait. I can't wait. So starting with calorie restriction, is there the best place to start? Like what do we wanna start with when it comes to calorie restriction?

Angelo Poli: So, we actually combed through hundreds and hundreds of research papers, and when I say research papers, these aren't like one or two sheets. These are in-depth to surface the most relevant. And so what I'll do is I'll share with you some of the highlights that we took away.

So, under benchmark clinical studies here, I'll just read, energy restriction is the most established method of weight loss and may be required in most, it's a heavy emphasis on most cases for significant weight loss to occur. But what's the problem? Weight regain after the initial intervention is consistent across essentially all research related to calorie restriction.

So there's the benefit and there's the rub, right? Calorie restriction is well-established and well-proven. But weight regain after is also well established in that genre. So the benefits and drawbacks associated with calorie restriction have been well documented over the years. And now I'm reading straight from the article here.

The short-term benefit of calorie restriction is fat loss. The drawback is the inability to sustain that fat loss over the long term. And here are some examples. one: in a clinical trial evaluating the treatment of obesity through calorie restriction, researchers observed an average of 8.5 kilograms, loss in participants.

At five months while following a 1200-calorie-a-day diet participants maintained approximately two-thirds of the weight loss a year later.

Crystal O'Keefe: Okay. So they lost eight pounds and then two a year later they had kept off some of that weight, two-thirds of that weight. Am I hearing that right?

Angelo Poli: Two-thirds of it. Yep. Kilograms. So that'd be a little higher in pounds. So there's quite a bit here to dive into. So this research study was procured as one of the more favorable. Okay, so you have to kinda look at research. You can't just blindly look at outcomes. You have to really look into how it was conducted, who the demographic was, what the situation was going in, to really determine the usefulness of the data in coming to a conclusion.

Crystal O'Keefe: You can't just be like, I was in my basement and I lost 10 pounds. And that's how that's gonna work for everybody. That's anecdotal, right?

Angelo Poli: And you'd be surprised how often there's this published research that says, oh, you know, research indicates that. And then you look at it and it was literally four guys in the basement doing this.

That's very weak data. It needs to be a larger demographic. It needs to be well-conducted and well-controlled. So, I've thrown out the extremes and all the wonky stuff. This was an excellent study conducted now, eight and a half kilograms. So that's about double in pounds. But I'm gonna encourage you to across the board, pay less attention to totals.

Well, obviously, whatever weight loss diet resulted in the most pounds lost is the best. Well kind of ignore that because total weight loss is more a function of how much weight that particular demo had to lose in the first place. The circumstance of the individuals coming in. What you wanna look at is trends, sustainability, and really read between the lines to see if is this effective or not?

In this case, we're looking at is this was a study that I actually will use to point out the relevance and the efficacy of calorie restriction. Because here you have a study that included quite a number of participants. It was standardized 1200 calories a day. Now we can, we can find a few things wrong with that.

That's not gonna support for the majority of individuals out there and the athletic lifestyle. But it is consistent with, you know, industry best practices and calorie restriction without getting really extreme or without being, too middle of the pack, and it did show a substantial amount of weight loss, and it did show two-thirds of that weight loss was sustained at a year.

In meaning that if you think calorie restriction doesn't work, this study actually concludes otherwise, but have a realistic expectation. In a best-case scenario, you're gonna maintain about two-thirds of the weight that you lose. That's in a best-case scenario. Now they're not all best-case scenarios.

Let's look at another study here. Another one, a comprehensive analysis observed that though many studies have been able to induce weight loss, maintenance of weight loss has been shown to be much more difficult. So now here you have another study that's competing with this. And what this study is showing, is across a meta-analysis, where it's taking what the researchers considered hundreds of quality, research, clinical studies, they came up with the number 54%. So instead of 66% maintenance, this study says it's closer to 54%. So where is it? At least you're getting a range from the experts basically saying that you can expect to maintain about half of the weight loss.

Crystal O'Keefe: Okay, okay. It's less exciting than two-thirds, but you know, hey, at least it's better than gaining it all back.

Angelo Poli: So right now it gets worse from here, here's another study. So that way, again, this is the way I like to approach research, is I like to take meta-analysis from multiple vantage points. So the good, the bad, and the ugly. So you can come up with a reasonable appraisal of the data. So now here's another perspective in this.

A handful of studies demonstrated that while calorie restriction is a valid method, it is flawed without being combined into a multi-disciplinary approach. I absolutely agree with that assessment. That is what we have learned both anecdotally in the trenches and statistically at MetPro. For example, and I'm just reading straight from our research results here, one randomized trial included two groups of obese women.

Now, this was a separate research paper that was just commenting on here. One group was counseled using fat restriction, that's calorie restriction at the end of the day. The other group using just straight calorie restriction, the weight loss averaged in the fat restriction group, 10.2 pounds and the calorie restriction group, 8.1 pounds.

Neither one of those numbers are relevant to what we're getting at. What we're seeing is there was some weight loss by reducing caloric intake. over the next 12 months, despite continued intervention, average weight among both groups returned to baseline. Ugh. And so now here you get kind of a third appraisal, which says they lost weight.

But a year later they were just back at baseline. And that's what anecdotally, we know we've done this before. We've watched what we've eaten. We've restricted calories, we've cleaned up the diet. A year later, how many of us kept that weight off? How many of our friends that we know did that, have kept the weight off?

And that would be in line with the researchers following this group. So now what you have is a group that says, when conducted well, when overseen, 66% weight loss maintenance. Another larger analysis says more like 54%. And now you have a group of researchers that's saying, yeah, the ones we followed, they kept none of it off.

So you're kind of seeing where the efficacy lands. a systematic review evaluating the ability to maintain any lost weight after interventions found the overall mean percentage of weight loss maintenance at 54%. That was the one we already looked at. In addition to sustained fat loss. An additional drawback from calorie restriction is a corresponding drop in metabolic rate.
Resting metabolic rate, RMR. The results of one study indicate that RMR decreased after calorie restriction beyond expected values based on fat-free mass. I'm gonna explain what this all means.

Crystal O'Keefe: Okay, tell me in normal people's terms.

Angelo Poli: So, in other words, calorie restriction, what these researchers are finding and there have been- this research is more recent. And there has been a number of studies that have come out really, honing in on what the researchers call, adaptive thermogenesis. And what this means is, in other words, calorie restriction can reduce metabolic rate further than what is expected from weight loss alone.

So for years, the prevailing thought and the researching community was, well, of course you lose weight, your metabolic rate slows. You're a smaller person. Smaller people require less energy. Makes sense. Those of us in the fitness industry, and actually the nutrition industry and the trenches knew for years also, that was not correct.

Crystal O'Keefe: There's more to it.

Angelo Poli: But since we didn't have the answer, we are just like, okay, well, you know, it was just like this gray area where we knew something didn't add up, but we didn't know what the answer was, so we just kept our mouth shut and went, huh, you know, it's obvious, and here's why.

And I give this illustration. If that's true, then you know, weight loss should basically be by the numbers. If you decrease so much, you should lose exactly so many pounds per week. So many, you know, weeks in a month, months in a year. And you can put it on the clock. And you know that if you look at the treadmill and the treadmill says you burn 400 calories or 500 calories, and you go times seven days, you're gonna lose one.

But what happens?

Crystal O'Keefe: None of that. None of that happens.

Angelo Poli: None of that. None, right? So in reality, how weight loss actually works. So studies aside, just you at home listening, you've experienced this. when you first start the endeavor. Weight loss actually often outpaces by the numbers. The calorie you just cut out, some soda pop, you just exercise for a few days a week, and all bam.

It's like you can lose 3, 4, or 5 pounds, just fall off if you did the math. You shouldn't have lost that much weight that fast.
Crystal O'Keefe: Or, you automatically go, I will lose this now every month, and if all I have to do is this and then that never works. Which is your whole point.

Angelo Poli: Exactly. Exactly.

You'll outpace it the first week. Okay. So you lose four or five pounds the first week and the second week you lose about what they say you're supposed to. And then the third week, it's a little less. In the fourth week, a little less by the fifth week, we hit a plateau doing the exact same thing. That's what we see.

Unless you're doing something very radical, that would extend out a little longer, but that's what a lot of people experience and that's essentially now. The mechanic that researchers can quantify, it's adaptive thermogenesis. So, in other words, beyond the fact that as a smaller person with less muscle mass and less fat mass, you require less energy to sustain yourself.

A host of metabolic adaptions take place, and this is the first thing we teach our clients at MetPro. It's not fair, and unfortunately, the reason you can't just take a pill to fix it is because it's not just one thing. It's a combination of the convergence of multiple biological systems having to do with hormones, insulin, hormone levels like the gut hormone, grelin and leptin.

And you have neuro peptides, the brainstem and the hypothalamus, and everything about how your body utilizes and expends energy. It's death by a million cuts. It's not one fell swoop. Your whole body acclimates when it feels it's under survival, assault. I don't have as much energy coming in as I used to.

And so it becomes more efficient. It can become more efficient in acclimating, adjusting your base metabolic rate, and then in a whole nother arena it becomes more efficient at allowing you to perform. Activities and exercise more efficiently. So now all of a sudden, the calories burned on your whoop and your Oura and your treadmill is now lying because it's not taking into consideration adaptive thermogenesis.

We're gonna put that on the shelf though. You know why?

Crystal O'Keefe: Tell me why.

Angelo Poli: Adaptive thermogenesis affects all modalities of weight loss except exercise. Now when you're just exercising to lose weight. Now the only thing that has changed, there's been no assault on your body as far as restricted intake. You're just expending more barring extreme cases where you're pushing your body to a death march-type workout marathon that then your body can go into.

But basically adding more exercise and activity tends to have a net increase on your metabolism, even if you're losing weight, but whether you're instituting weight loss via calorie restriction, carbohydrate restriction, periodization, intermittent fasting, any modality, you're going to experience a measure of adaptive thermogenesis, which will address in part four how we combat that.

But for now, we'll put that on the shelf and we're just gonna look at is calorie restriction effective. Finally data shows, and now I'm just reading again straight from the article. Calorie restriction of the long term can be difficult. Evidence suggests that in some individuals genetic environment and additional factors like that can result in obesity.

One study sheds some light on the numerous pathways. I just mentioned that leptin and grelin insulin all play a role also now in appetite, and therefore weight stabilization. While calorie restriction is a well-established method of weight loss data consistently show that weight regain happens after the initial intervention period.

The factors in this study, Explain in part the challenges inherent in weight loss and weight maintenance thereafter. While calorie restrictions and strategy, uh, has well-documented weight loss results, calorie restriction has negative effects on RMR contributing to weight regain.
Additional physiological factors also impact weight loss maintenance, the pancreatic hormone, insulin, the gut hormone, grelin, cytokines like leptin, and even parts of the brain. Hypothalamus, brainstem, as I mentioned, all play a role in regulating homeostasis and appetite, and all these factors contribute to both behavioral and physiological difficulties in maintaining weight loss.

So it was at this point in our research that the obvious question, the protagonist of the story, presented himself or herself, and that is, calorie restriction is indeed an effective means of weight loss, but how do we combat the associated metabolic decline, associated behavioral up and comings and the weight regain at the end of the day, at the end of the period or intervention?

Here's what we found. This is our honest effort to extract the best data we could with what we had available to us. And at MetPro, we have no indefinite data, but we have some very good quality because our clientele is highly engaged, so we have very good data. So here's a retrospective analysis that included a population of 57 obese females, ages 27 to 65 years old with A BMI greater than 30.

So just real quick on that BMI. That's the fine print that most people don't look at. Again, total weight loss results is gonna be indicative of really who the people were in the first place. So look at the trend over the total numbers. So BMI of 25 to 30 is considered overweight, right? BMI of over 30 is considered obese.

And then it's higher for morbidly obese and et cetera, et cetera. But that's basically the demographic we're looking at here. Now, in this research study, we conducted a retrospective analysis, and participants were coached on the MetPro multidisciplinary approach for over a year. So, we wanted people to have a history of data to qualify for the analysis, participants had to be actively engaged. That doesn't mean perfect, that doesn't mean we cherry-picked anyone. Simply taking a snapshot at, three months, six months, and one year, they were still active again, we didn't cherry-pick ones that were the most consistent, just simply accurate, which is more apples for apples. What we are doing in the studies that produced the better outcome they were looking at, they were kind of discarding the bad research and looking at here's the studies that produced a successful outcome. What were the numbers? So that was more the 54%, 66% numbers.

Here's what we found. Comparisons were made at three months, six months, and one year. Weight loss percentages were calculated using total weight loss relative to the initial weight. Prior to beginning MetPro at six months participants. Median weight decreased by nine. Point zero six kilograms or just under 10% body weight.

That's probably the more relevant number. Uh, 25% of participants lost 13.1% of their body weight. And generally so with most research, the minimum weight loss percentage that is considered successful or effective as an intervention is about 5%. Now, depending on the researchers and what's being studied, that'll vary.

It might be a little lower, but 5% is kind of the unspoken standard when you look at most research. 75% of all the obese women in this study, uh, lost more than 5% of their body weight within the first six months at the end of one year.

Crystal O'Keefe: Wow. And that's the really important part because now we're looking at the regain.

Angelo Poli: Right. This is the really important part. At the end of one year, there was a further weight loss of up to 10.16 kilograms. Median weight loss stayed consistent across the entire participants. At 9.3 25% of that group lost more than 16.8, so some 25% of the top quarter went on to perform really well, 16.8% of their body weight during that time period.

Here's the notable part. At the end of one year, during the time period, typically associated with weight gain, weight loss continued. Why is that significant? Is it because, oh, well, somebody using this multidisciplinary approach lost exponentially more weight than caloric restriction? No. A little bit more, a little bit more on average.

The big defining difference was a multidisciplinary approach. enabled them to continue. The graph was linear in that weight loss was greater over time, or at least never backslid on average. Whereas with other approaches, I mean you can get radical. Some people go on these, you know, liquid diets that's gonna produce significantly more weight loss out the gate.

But what happens in virtually all cases over time, they just gain it back. Precisely. So the real protagonist is how do we manage the metabolism during the process so that way the weight regain phase is not inevitable and surprise, surprise, taking a more athletic approach to it, taking a more metabolism-focused approach to it, produced a preferable outcome you know.

Of course, that is my biased opinion, but here's the data. The numbers are the numbers. And so what we saw was a very good outcome with this group. Now, this was a population of obese females. As we continue through the research, project, we're gonna have other demographics and other populations to compare against and see what we can learn.

But that was, that was basically a recap of what we learned about calorie restriction. If you're considering that as a relevant modality, is it real? Is it relevant? The research says yes. Yes, it absolutely is. Can it be optimized? Yes, it should be. And you may want to think twice about installing caloric restriction independent of any other multidisciplinary approach. You wanna have multiple approaches supporting your metabolism that go into it.

Crystal O'Keefe: Wow. Okay. Well, that was incredibly eye-opening. Again, this was part one of our special mini-series of the podcast. This was all about caloric restriction. But Angelo, you're gonna be back soon and we're gonna also discuss carbohydrate restriction in the next episode.
Well, thank you so much for your time today. I really appreciate it. That was very interesting.

Angelo Poli: It was a blast as always, Crystal, thank you.

Crystal O'Keefe: Thank you, and listeners, that's all for this week. You can find all the MetPro Method episodes anywhere you get podcasts, or you can go to

Please be sure to follow the show and rate and review. That lets other listeners know what to expect, and I will be back next week. Until then, remember, consistency is key.

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