Science to Transform Series: Carbohydrate Restriction for Weight Loss

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

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

Angelo Poli: Oh my gosh. Thank you for having me, crystal.

Crystal OKeefe: Today I wanna talk about some amazing research that we've been working on, and I'm gonna get to that, but I do want to address anybody that might be watching on our YouTube channel.

Um, I, uh, I have some bruising on my face. I look like I've been hit by a car. That's cause I was. You know, this happens. It happens to people.

Angelo Poli: Oh, my goodness. You are such a trooper for even being here today and being upright.

Crystal OKeefe: I am so happy to be alive. Like really? I'm just like, hey, I feel really good, especially compared to last week.

So, you know, I just want people to know who might be watching. I am okay.

Angelo Poli: Wow. Wow.

Crystal OKeefe: And so to dive right into the episode, we started a four-part mini-series of the podcast last week. And, it was talking about research that MetPro has done that we wanna share with all of our listeners.

And the first episode, we talked about what that research was and we did a deep dive into the findings on calorie restriction. But today we're gonna take a little time and we're gonna talk about carbohydrate restriction. So, Angelo, I'm gonna turn it over to you. What does the research say about it?

Angelo Poli: All right, well, just recapping from last time, the research says calorie restriction is a viable method of body fat reduction. No big surprises there. What does it say about carbohydrates? So, I'm just gonna read clips from the article and we'll just do some commentary on it. The benefit and drawbacks associated with carbohydrate restriction have been well documented over the last couple of decades, and it has, there's an abundance of research.

Clinical studies try all kinds of different research that have been done in controlled settings on this topic. So what do we learn? Carbohydrate restriction results in faster initial weight loss and may help stabilize appetite and reduce sugar cravings. That's essentially what the body if you were to get the one sentence Cliff notes, that's what we come out with and I can attest that that's accurate, and what we've observed here at MetPro.

However, now here's the asterisk that's gonna go on in every modality. There is no one, silver bullet. There is no one solution for everything. When accounting for water balance and increased sensitivity to carbohydrates, the longer-term benefits of carb restriction become less clear.

So it is very stark when it's just really short term. We're talking in a matter of days. Now, when you go to the longer term, that's where it becomes a little bit tougher to tell the difference because there's some conflicting evidence. The longer-term benefits become less clear and increased carbohydrate sensitivity can be a trigger leading to yo-yo dieting. So what does that mean? Ever seen that Crystal?

Crystal OKeefe: Oh, I've definitely seen that. Can you spell out what that means though for people who may not be familiar with that phrase?

Angelo Poli: So that's the scenario where you've been following an eating plan, whether it's clean eating, low calorie, low carb, and then you just plow into a weekend and you go out with the girlfriends, you go out with the guys and you have, chips and burritos and the whole nine yards.

And then all of a sudden, Monday you wake up, your weight's up. And so now you start being more restrictive and you turn into nearly starving yourself for a few days, and then overeating for a few days, not eating for a few days.
That is a very destructive but easy pattern to fall into everyone. To a lesser, a greater degree falls into it. And so that's where you have to be a little bit discerning when it comes to carbohydrate restriction. So let's get into the science. Let's get into the studies. In one randomized study comparing very low carbohydrate diets with calorie-restricted diets, researchers demonstrated that restricting carbohydrates resulted in greater weight loss than calorie restriction alone.

Full stop. Makes sense. No, you have it. So, is there validity in researching it and considering it? Absolutely. And we've actually found many research articles with that overarching theme. But as I did last time. You have to look at the body of research through the lens of application and what's relevant to really determine how this is gonna apply to me.

So here's what another study observed. It observed reductions in food cravings within four weeks of a carbohydrate-restricted diet. Women experienced a greater reduction in sweet cravings within four weeks, and it was a little bit more pronounced for women than for men. So, another feather in the cap of, okay, there's validity to restricting carbohydrates.

Now let's get to the other side of the coin in another study. Significant differences between weight loss between high. So 45%, that's not really high carbohydrate. 45% of your diet and low 15%. They didn't see any differences. Yet another study in a short inpatient study. Now carry in my book a little bit more weight because that's a very controlled setting.

They're being given their food. They're usually in a hospital or clinic setting.

Crystal OKeefe: So, in theory, everybody's playing by the same rules, if you will.

Angelo Poli: That's it, that's gonna be relevant in a moment here. Now another study observed that a more controlled setting resulted in more body fat loss with dietary fat restriction, even though total weight loss was greater in the reduced carb group.

So, this is a study that basically, was a shorter-term study. Two groups of patients were given their food. One group was low fat, the other group was restricted carbohydrate. Now the carb-restricted group in the short term is almost always going to show a greater weight loss on the scale, but that's because of some dehydration, glycogen depletion results in water loss.

That's not necessarily long-term weight loss. That's water balance. When they corrected for that, the water balance equation, what they found is that the fat reduction group, at least in this study, actually lost a tad more body fat. Interesting, right? Another study. A similar outcome was observed in a study comparing carbohydrate-restricted and fat-reduced groups. Of the two, the carbohydrate-restricted group experienced greater total weight loss.

Again, that water balance. The reduced fat group experienced less adaptation to carbohydrate and fast restriction and had a little greater fat loss than the carbohydrate-reduced group. So was this a one-off study? No. Here are more studies basically saying the same thing. So how can that be right? Because that seems to be some conflicting data, right?

Crystal OKeefe: Sure does. Yeah.

Angelo Poli: So if we look at it through the lens of what's going on behind the scenes, why is it now in a clinical setting, the results seem to be a little bit more parity whereas, in more of an outpatient setting, a user identifies, here's what I ate, it's showing greater weight loss with the carb restriction behavior.

So, this is outside the scope of the research, so I'm giving my opinion on this, but you'll have to listen and see if it has the ring of truth to you. Watching thousands of people diet over the years. I can tell you scenarios where you give somebody broad rules, okay?

You're just going to cut carbs. Rules of engagement are a little easier for that person to wrap their head around. So compliance might be higher. I'm just presenting a hypothesis here. If I say, now what you're gonna do is you're gonna follow a routine where you're eating, you know, 230 grams of carbohydrates and you're having this many grams of fat.

You could try your best, but the reality is there's gonna be a large delta without having a game plan and, actually built meal plans provided for you and help to build those meals. If you're just left to your own devices, that's very hard to accomplish.

Crystal OKeefe: Heck yeah. Yeah, it is.

Angelo Poli: That's the number one thing we've learned at MetPro which is why we, you know, all of the tools.
or to help people provide that. Otherwise, you're gonna spend hours in the grocery store reading labels. You need some tools that make that easy. So what's happening is in the self-reported data groups, it is likely that there's more. Straying from the plan when somebody is just following a reduced calorie, some's coming from carbs, some's coming from fats, you're probably getting a little bit less reliable data.

That said it is clear that carbohydrate restriction has an impact should we implement carbohydrate restriction. Well, there's one more factor to consider. Athletics, fitness. So in our next session, we're going to see the staggering data that is in favor of all the reasons why fitness should be part of your ongoing weight maintenance body composition routine.

So will carbohydrate restrictions support that? And the answer is, it depends. . So here's what another study observed. Another study compared obesity treatments using carbohydrate-containing and carbohydrate-restricted hypo caloric diets. So in this study, this was very low-calorie intake. on both. One was also low carb, one was the high carb, but both of them were very low calorie.

Researchers observed a significant decrease in endurance during cycle exercise at approximately 75% VO2 max in the carbohydrate-restricted group that was not observed in the low-calorie group. Pre-exercise muscle glycogen did not change significantly in the low-calorie group but decreased by approximately 50%.

In the carbohydrate-restricted group, the results indicate that adding significant carbohydrate restriction to a hypo-caloric diet impairs performance. So there's the rub. If energy is being limited, and we drastically decrease. So, kind of in layman's terms here, if we drastically decrease glycogen stores of carbohydrates, what's gonna happen is your athletic performance is, is going to suffer.

It's not going to support your best exercise, either energy or performance. They actually did muscle biopsies here and found a 50% reduction of fuel inside the muscles. So it's something that we have to be wary of. So what does this all mean? So here's the bullets. First, carbohydrate restriction results in greater total weight loss than calorie restriction alone.

So,, we wouldn't simply dismiss it. Second, the difference between total weight loss with carbohydrate restriction compared to calorie restriction is dominantly water balance. When you look long term, when you go, okay, what's the result at six months a year out? The delta is usually just water composition.

Um, when you carry it out over though appetite is subjective, carbohydrate restriction does correlate positively to appetite control in most studies. And I would add to that, that that passes the sniff test. In our experience, right, working with people, we find actually in MetPro, when we take someone just entering a metabolic revving cycle or actually gradually increasing carbohydrates during a revving cycle, that's when the appetite actually goes up the fastest. So that passes the sniff test that seems accurate. Carbohydrate restriction may result in more adaptation to carbohydrate restriction than calorie restriction alone.

This is the crux of the conversation when it comes to application. What does that mean? It means that when somebody restricts carbohydrates, their body becomes more sensitive to carbohydrates than if they were just cutting calories. Now, last time we read the research on adaptive thermogenesis, that applies to any form of restriction, whether you're doing carb restriction, calorie restriction, or any form of restriction, but you get an extra sting with carbohydrate restriction, and that is your body becomes sensitive to carbohydrates Now, is that right?

Does that pass the test? Does that seem logical?

It does be because of the glycogen stores, right?

So anybody has experienced this, let's say you're cutting calories, you're just eating cleaner, you're watching what you eat, and then you have a weekend off and you eat a little too much, but you gain a little bit of weight.
Yeah. But it's nothing compared to anyone who's been on a low-carb diet and has gone two weeks with very little carbohydrates, and then they're on vacation for the weekend. The weight just comes flying back on. So that's where that carbohydrate sensitivity comes in. So degree matters, but this is where you can't separate the behaviors from the science.
Let me give a few further comments on that, but I wanna read the last bullet, before that. The last bullet is that carbohydrate restriction of significant magnitude results in decreased muscle glycogen and may impair athletic performance, which may be a little watering down.

The truth is it will impair if it's of sufficient magnitude. So when I have this conversation with somebody who's just asking, well, what do you think? Should I go Weight Watchers or should I go keto? Am I cutting calories or am I, because you have the proponents on one side or the other?

Here's what a body of evidence indicates. They're both relevant science. The carb restriction has some short-term benefits, but some hefty short-term consequences. So I usually will ask the person, are they the type of person that sticks with something really consistent without even minor deviations for extended periods of time?

Yeah. Because if not, you're gonna get all the carb sensitivity and very little of the benefit.

Crystal OKeefe: Which is why it never works for me.

Angelo Poli: Well, that's the challenge. So when people ask, well, in MetPro, you do not do carb restriction? No, we do carb restriction. We do not apply extremes. You're never gonna be on 10 grams of carbs with MetPro, it's gonna be very moderate, of course. Um, but we implement carb restriction, but we do it in a systematic way where we're gonna have a hierarchy.

So what's our hierarchy? Well, we could do a whole, we could do a whole lecture on this, but the bullet is number one, toleration. So, it's worth saying, that there's a greater percentage of the population that are going to be intolerant of carbohydrate restriction than there is simply calorie restriction.

In fact, there are a lot of people that you cut out carbs and they're gonna feel awful. And there are some people that are fine. There are some people that are fine, but that's the first thing we would have to look at. Second thing, at what point is it impacting your athletic performance, your recovery, your ability to exercise consistently, and if we are even dancing on that, it's a no-go.

It's a no-fly zone because we have learned long-term. Statistically, the best outcome is going to be any diet application within the framework of regular exercise. Even if that regular exercise is for you taking the dogs for a walk around the block, wherever you're starting, there has to be some regular, consistent exercise.

You're always going to have a better long-term outcome. So we don't wanna cross that threshold where we're borrowing from Peter to pay Paul, and we're damaging our ability to exercise to get more extreme here. Right? Third, are we making progress? Here's a little insight that most people don't recognize.

How come Angelo, your team is coaching my friend and she's not eating a whole lot of carbs and I'm eating a lot of carbs. What's the difference? Well, the difference is we have assessed while watching your metabolic rate.

That you are making progress without needing to cut more carbohydrates. So we can always hold that kind of the ace in the hole, so to speak, if we need to. We're not having to trigger that carbohydrate sensitivity as soon as we trigger that. Then when you do have a real-life weekend where things aren't perfect, when it will happen, your body's not gonna be in such a sensitive state.

So that's the hierarchy. So what we look at is toleration, athletic progress, and then our levers are we're gonna use a combination of carbohydrate restriction and calorie restriction, and we're gonna blend that together nice and in a nice, tidy way instead of relying all on one or all on the other and then finally periodization where we're gonna trigger and say, okay, you've been restricting carbs long enough.

We're not gonna continue to do that because your body is no longer giving it up. Right? We need to change something. So, that's where we go through cycles. And so here's what our data has shown. We did an analysis, a retrospective analysis, and this was a large database of clients. A retrospective analysis included a population of 112 overweight and obese males, 29 to 69 years of age, with a BMI of greater than 30.

So, this is going to be people that have some weight to lose. The average weight for this came out to 245.71 pounds for the males in this retrospective analysis. Participants were coached in the MetPro multidisciplinary approach for over a year. To qualify for the analysis, they had to be actively engaged, data tracking for at least a year.

Comparisons were made at six months at one year relative to the program's start. Now here was the results. At six months, the average weight loss was 23.4 pounds, approximately 10% body weight. At the end of the year, now here's the part that matters because you can get caught up in total body weight, right?

So you are always gonna find a research study that shows this is the, the total, we know what the fastest weight loss is,

Crystal OKeefe: And the year is about the time that people start to regain. That's why a year is such an a, an important data point too, right?

Angelo Poli: About, actually, it’s about the three to five month mark.

Crystal OKeefe: Oh, okay.

Angelo Poli: Is what we start to regain. So if you look at the arc of most long-term weight loss studies, you're gonna see that the initial 10 to 12 weeks is usually what's called the weight loss period. Now, depending on how the research is structured, it could be three, four months, but typically, you're gonna see the greatest weight loss at, around the three, four month mark.

Maybe a little longer, but definitely months six through 12. That's the time period where now how much does the person regain? That's the difference. That's where the data on carbohydrate restriction doesn't always look as pretty. . So here's what we found. They lost approximately 10% of their body weight in the first six months.

At the end of the year, average weight loss percentage remained consistent. Wow. So they were able to keep that off. Now, this isn't, oh, you know, we've figured out some magic combination of these three foods. I'm sorry to disappoint. Here's the, the secret is they're working hard. They are doing some exercise.

They are consistent with food and clean eating, but these are not people that are on some gimmick starvation program. These are not people who are only eating 20 grams of carbs the rest of their life. There are periods where we're being a little more restrictive, but we're cycling back around and keeping them on a much more athletically focused routine and this is why you're seeing results like this.

Crystal OKeefe: I mean, that's incredible because if you look at last week when we talked about calorie restriction, there were studies that said, Hey, with just calorie restriction, you, some studies said you could lose weight.

Some said you were gonna lose weight, but then you gained some back. Said you didn't lose any at all.
Angelo Poli: And so the take home message for anyone is that it doesn't have to be an either or you can apply. A multitude of disciplines when they're choreographed intelligently. There has to be a plan, there has to be a strategy and next steps. But the combination of some calorie manipulation and some carbohydrate control seem to work, and our experience seemed to work really, really well.

Now keep in mind , the data and the research that I look at, this is really. successful trials. This is not talking about the, my next-door neighbor went on this, no carbs for two weeks. And then in those situations, the truth is, more often than not, the person ends heavier than they began and what they experience is one to two weeks of weight loss and then a month of weight gain and they end up in this yo-yo scenario.

But that can happen with any modality. And so, you know, if we're being fair, what we're contrasting is carbohydrate restriction versus calorie restriction. And any modality you approach you have to be consistent with it. You have to take an analytical, strategic approach to, here's how I'm gonna implement this from my body.

But if you do, you can get really good results.

*Crystal OKeefe: * So what I'm hearing is no magic bullet, lots of science, lots of hard work.

Angelo Poli: Well, sorry to disappoint. No magic bullet, but the research is there and it indicates, basically, it mirrors what we have found at MetPro.

It all makes sense when you play it out. So stay away from the gimmicks. But there is good science in both carbohydrate restriction and calorie restriction.

Crystal OKeefe: Well, Angelo, thank you so much for your time today. I look forward to having you back to talk about the exercise effects on body composition.

That'll be part three. 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 people know what to expect. You can also learn more about

I'll be back next week. Until then, remember, consistency is key.

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