A surprising cause of undereating after bariatric surgery can lead to weight loss resistance.  Check out the audio transcript to learn more.

Is Undereating after bariatric surgery causing weight loss resistance

Dawn (00:00):

Hello and welcome to the Gastric Health Show. My name is Dawn Boxell and I am a Registered Dietitian. And this week’s topic: is Under-eating after bariatric surgery causing weight loss resistance? I wanted to bring this topic to light because I see this very frequently, and if I’m being honest, I see this frequently even with just people in general, the amount of undereating that is occurring is a lot. And I want you to understand just some essentials about your metabolism, the connection of metabolic adaptation, just what really can add to weight loss resistance after bariatric surgery. And the amount of calories that you’re consuming truly can be a driver. So let’s kind of dig into this. I would say when it comes to weight loss resistance, most people think less is more, meaning that the fewer calories you consume, the more weight you will lose.

The Calorie Deficit

(01:22):

And in reality, being in a calorie deficit is needed for weight loss. It’s just kind of this fine line that you have to kind of ride on because you have to eat enough to fuel your body, but yet you do have to remain in a deficit. So it gets a little bit complicated to think about, but I am going to hope that this will make it as simple as possible so that you can really, I guess, understand if maybe undereating is driving your weight loss resistance. Now by design, having bariatric surgery does lower your calorie intake. So that’s kind of the whole gist of having bariatric surgery. The whole concept that the reason why people are overweight and obese is because they consume too many calories is really where this is driven from. Kind of that whole calories and calories out model that hey, if you eat less and just exercise more, then you will attain weight loss.

Burning calories

(02:43):

And we all know that that really is not how our body works and we’re not just some mathematical equation and you just consume 500 less calories, burn an extra 500 calories, and BAM, you’re going to lose a pound a week. I do remember learning that in college, and I do remember practicing that we would do indirect calorimetry and we could measure your metabolic rate and kind of pick your calories off of that. Then we’d also have a BIA.. Tanita scale, which is A BIA, and we would measure people’s muscle mass and fluids. We would monitor that on there to get a good idea of how much we should be feeding someone and where that magic sweet spot should be with weight loss. And I can honestly tell you, I did this a lot for probably a few months and I was just as many people as I could put on the Tanita scale and as many people as I could do indirect calorimetry with, I was doing it.

Perfect calorie number that everyone should attain

(04:03):

It was encouraged to whatever we needed to help this person be successful was really what we needed to do. So that was if I had somebody who was stuck and they weren’t losing, this is what I would do. And I can tell you that I don’t think I had one person that was successful out of let’s say a six month period. I did this on probably or three or maybe five handfuls of people. And I can tell you that it was frustrating for them and frustrating for me, and it just never quite panned out to be as successful as what you would have hoped. So I want you to understand that there’s not necessarily just a perfect calorie number that everyone should attain, and that calorie number is going to be the same every single day of your life. It’s unlikely to be that stable of a number because your activity fluctuates and the intensity of your activity fluctuates.

Maintenance Is Important

(05:29):

So if we just said, Hey, you had bariatric surgery and I want you to follow 1200 calories, or Hey, I want you to follow 1500 calories, you’re a female, you get to follow 1200 if you’re a male, you get to follow 1500 and that’s what we’re going to use for weight loss and that’s what we’re going to use for your maintenance. And we want you to stay on that long term and would say, I would want you to challenge that. I would want you to challenge that thought process because it is not that simple that our calories are just that stable for us day in and day out. So the big picture I really want you to see is that I truly find a lot of bariatric patients are truly just undereating. They consume under their metabolic needs, and this is what’s getting them hung up in weight loss resistance.

The Metabolism Mystery

(06:35):

So kind of stick with me here as we dive into some of this. And I know some of this may not be simple to process, but I want you to just try to grasp the big picture of what we’re trying to say. And that big picture is you can’t consume long-term. I’m not saying short-term, but long-term you can’t consume less than your metabolic needs for a long period of time under that resting or that basal metabolic rate where your body, that this is the rate of what your body needs to sustain life, this is the calories that your body uses for your heart to beat, for your food to digest, for your brain to think, your lungs to expand, for your blood to flow, all of that stuff that we don’t have to think about that our body just does that requires calories and you can’t eat under that need for life and not lower your metabolic rate and not influence how your metabolism is going to function.

Metabolism is truly the goal

(07:58):

So to kind of just recap a little bit, first I want to say that in order to lose weight, you do have to keep in mind that a calorie deficit is beneficial and the key to consuming enough calories to support your body’s functions without adversely affecting your metabolism. Metabolism is truly the goal. So what is undereating? Let’s dig into that piece of painting, that picture of helping you understand, am I undereating or not? So having inadequate calories or yeah, we’re just going to leave it as inadequate Calories. are not simply just a matter of consuming fewer calories. Rather, undereating refers to the

What is undereating?

(08:54):

Chronic restriction of caloric intake to the levels below your body’s requirements for essential functions and daily activities. So again, that’s where we’re going to that metabolic rate and the lower that your calories are chronically that they stay in this low state, it influences and slows that metabolism down and adapts to that lower calorie intake. So in context, post bariatric surgery, undereating typically involves chronic calorie consumptions between 900 to 1200 calories a day. That’s pretty common. So let’s kind of, let’s dig into the reasons why a bariatric surgery patient would be consuming 900, 1000,1200 calories daily after bariatric surgery and why this could be considered under eating, meaning you’re not consuming enough calories consistently to meet your basic needs for your body to function. So first off, there’s no way around this one. The initial post-surgery diet restriction, this is part of it. This is giving you that restriction, that calorie restriction that helps support great weight loss and by design, bariatric surgery is kind of setting you up.

Undereating Defined

(10:47):

If you don’t look at this at a high level. And if you don’t understand this, then it does kind of set you up for that undereating pattern. And this is where understanding this piece is so important because you can have surgery and if you stay at that chronically low calorie intake for months and months and years and years, that’s when it’s hard to get that metabolism to really get cranked back up without good effort on your part. So after surgery, your diet slowly progresses in textures and on volume. So you start out pretty low. I would say most of the time when I was seeing patients at the bariatric center that first month, I would say most typically it was five to 600 calories. Our goal was 800 calories and we could rarely get people there. So again, 500 to 800 calories was really kind of where it landed for your intake on a daily basis in that first month.

Initial Post-Surgery Eating Restrictions

(12:05):

Now, a few things that kind of drive that one, not all centers follow just one diet. So I will say, which I find interesting, some surgeons like to keep you at lower volumes. Some surgeons give really tight tiny pouches. Again, some of this you may not have control over because they’re not in there measuring with measuring tapes and making sure that it’s exactly the same pouch for everybody. Everybody’s stomach starts out of the size of a football and they take it down to the size of an egg or golf ball size. So again, some of it you can’t control but working with your dietitian, this is where it can help you understand because it’s hard to see. You get confused because you feel really full and satisfied, like you literally just ate a Thanksgiving meal, so you feel like I’ve eaten enough where in reality you may not be consuming enough.

Fear of Weight Regain

(13:15):

So this is where working with your dietitian is so important, but this premise of what the bariatric surgery is all about, about restricting volume with that premise that people are really the problem and they’re overeating, but in reality, that’s not the cause of weight gain. It is your metabolic health. And that’s why it shifted from just bariatric surgery to a bariatric and metabolic surgery. So again, it’s important to put all this in perspective that initially you are going to be eating very few calories, but here’s the thing, your body can handle that and adapt to that short term, but it’s important as the weeks and months go on that you grow that volume and you grow and increase those calories because your body needs them. So that’s the first reason why under reading why someone would be undereating after bariatric surgery. It’s really just the initial phase and this just comes with the territory.

Physical Discomfort

(14:28):

The next one is maybe some discomfort. So if you maybe have some symptoms when you eat food just sits like a brick, it feels heavy, it’s uncomfortable, makes you maybe even feel a little nauseous that could prohibit someone from wanting to eat and do all that they need to do. If you have a lot of discomfort with eating, this could be that your pouch is so tight and it’s just hard to get all of your nutrition in. So it’s kind of like it’s inadvertently leading you to undereating. It’s not by choice. So these first two, none of these are by choice really. So again, that’s where I want you to say, okay, bariatric surgery is starting this for me and then I need to take it from where it is and grow this and stretch my pouch and expand it so that I can hit my calorie needs.

Misconceptions About Caloric Intake

(15:31):

The next one is misconception of calorie intake. This is where it gets to where you are intentional, where you are maybe misinformed or you have a belief system or you are stuck in diet culture that eating fewer calories is the only way you’re going to lose weight. And I want you to see that your metabolism is not that simple. It’s more complex and that it’s not all about calories in calories out and the more you restrict and keep your calories low chronically is what can lead to weight loss resistance. And then the last one is fear of weight regain. Literally, I have never met a bariatric patient who hasn’t had a fear of weight regain. And I get it. There is valid feelings and I definitely understand this and support you in this feeling, but I do encourage you to push through that feeling and don’t live in a state of fear. Living in that state of fear of regain, what if I do, what happens when… don’t live in that state because that is not a healthy state to be in.

Metabolism and the Imperative of Caloric Sufficiency

(16:56):

And don’t let that be the driver of why you keep restricting food and why you are undereating because you have this huge fear that you’re going to regain weight. And I want you to learn and grow in confidence that you should be eating. You should be fueling your body and providing it with the nutrients and the calories that it needs to maintain a stable weight. So your metabolism and calorie sufficiency. So in the human body, metabolism refers to a series of chemical reactions that are responsible for maintaining life by converting food into energy that is required for all your body functions such as breathing, digestion, thinking, moving, your heart beating, all of that. The impact of undereating on metabolism can be summed up in two key ways. 1. Slowing the metabolism and 2. Metabolic adaptation. So slowing of the metabolism, an extended period of low calorie consumption gives the body kind of this impression that energy is scarce and triggering a metabolic response that conserves energy.

Slowing of Metabolism

(18:26):

So kind of that starvation mode that you’ve probably heard of that your body conserves when the calories are inadequate. Because it doesn’t know if it can rely on you to provide its next meal. According to studies, when the consumption of calories is consistently low, the body reduces the energy expenditure to conserve resources or it lowers that metabolic rate to conserve its reserves. And as a species, we have kind of adapted to this survival mechanism over the course of time. As a result of energy conservation, the body burns fewer calories at rest while exercising. So what this does is it lowers your metabolic rate and then to conserve those calories because it doesn’t want to burn up your reserves and utilize your stores because it won’t have enough to sustain itself to keep you alive, if you continue on this path. And if you’ve been doing it for a long period of time, that is where it all begins.

Metabolic Adaptation

(19:46):

So the next is metabolic adaptation. And as a result of prolonged calorie restriction, the body becomes more efficient at utilizing the limited energy it has at its disposal. So weight loss doesn’t occur because fewer calories are expended during day-to-day activities and according to research, chronic undereating triggers the body to become more efficient in using the limited calories that it receives by enabling the body to utilize the calories at a higher rate. As a result of this higher efficiency, fewer calories are expended during daily activities making calorie deficits harder to achieve. So what factors trigger your metabolic slowdown? So 1. Adaptive thermogenesis, 2. Hormone changes and 3. Loss of lean body mass. So these three things, if you think of the adaptive thermogenesis is the ability for the body to adjust its metabolic rate in response to the changes in calorie intake. And this is what’s known as adaptive thermogenesis. Your body perceives that too few calories as a threat when you consistently consume too few calories. So the adaptive thermogenesis is initiated to conserve the energy and among other things, this also includes reducing the speed at which your body burns calories at rest. Also knows as you’re known as your resting metabolic rate.

The Bariatric Patient’s Dilemma

(21:38):

So, so if you want to have a metabolism that is super efficient and working for you even when you are not working out, that is all about this adaptive thermogenesis. So if you are lowering that resting metabolic rate, then guess what? You are not going to be burning calories and able to maintain a lower healthier weight because your metabolic rate has been shifted to lower calories because you’re consuming too few of calories. Now, several studies have shown that prolonged calorie restriction decreases that resting metabolic rate. So again, it just goes back to evaluating what you do. Are you truly consuming a sustainable amount of food and calories that you aren’t shifting this metabolic rate, your resting metabolic rate to burn slower, to slow your metabolism? So it’s something that you have to think about. And again, I find this with a lot of clients that come to me.

Under-eating & weight loss resistance

(23:06):

They are undereating. They are not consuming enough calories to sustain a healthy metabolism. So we have to work on increasing the food that you’re consuming so that you can raise your metabolic rate. So number two, the hormonal changes. It’s also important to note that chronic undereating leads to changes in your hormone profile that can slow down your metabolism. And the hormone leptin, which produced by fat cells plays a crucial role in energy and metabolism. And when you consume too few calories, your fat stores decrease reducing leptin levels. Remember, leptin is kind of that satiation hormone. That’s the one that kind of says, Hey, we’re full. We don’t need any more food. Low levels of leptin signals to the brain that the body is in a state of energy deprivation, which triggers energy conservation mechanisms. Again, you’re telling your body that we need to conserve energy, we need to slow our metabolic rate because we’re going to burn through these calories way too fast and if we don’t slow it down, we’re going to be in trouble.

Leptin affects metabolism in response to calorie restriction

(24:25):

Our life is in trouble. There have been numerous studies showing that leptin affects metabolism in response to calorie restriction. Leptin levels decrease, which affects energy, expenditure and appetite. As a result of this hormonal shift, the body slows down its metabolism and increases hunger, making weight loss even more difficult. Again, you are shifting these hormones in a way that can set you up to feel very frustrated thinking that it’s you that is doing something wrong when really it’s just you need to fuel your body better, you need to provide it with the nutrients that it needs so that you can keep a normal metabolic rate, a loss of lean body mass. I have talked about muscle quite a bit and I want you to know that this is an important piece as well when it comes to undereating. So chronic undereating can also lead to a loss of muscle tissue.

Understanding Metabolic Adaptations and Appetite During Weight Loss

(25:36):

So we know the more lean muscle mass that you have, the higher your metabolic rate is. So if you one are not fueling your body appropriately with enough calories, but even with enough protein, this can shift your metabolic rate. A lack of protein intake can result in muscle loss as a result of calorie restriction and the loss of muscle mass contributes to a lower metabolic rate. Researchers have shown that calorie restriction without adequate protein consumption results in a reduction in lean body mass and metabolic rate. So what we’re saying is it’s, it’s the whole package. You can’t, not all calories are equal. You can’t say that I eat 1200 calories of broccoli and 1200 calories of Snickers are the same. Your body is not going to respond the same to those two different food sources or calorie sources. So not only does your body need adequate calories, but it also needs adequate protein to protect your metabolic powerhouse, your muscles.

The higher your metabolic rate

(27:10):

So the more muscles that you have, the higher your metabolic rate is. And that’s why, again, if you want to boost your metabolism, add in strength training, that is the best way to help support a healthy metabolism is just really using your muscles and then consuming enough protein to protect those muscles and keep them stable. So kind of the calorie dilemma after bariatric surgery is where we’re going. Now, if weight gain begins, the mindset of a lot of bariatric patients is to cut calories or undereat. So again, you go back to diet culture saying eating fewer calories is the only way you’re going to lose weight is what your brain may be telling you. But in essence, it might be that you’ve kind of chronically under eaten and now we’re at a place where your metabolic rate is low and we have to kind of eat to help increase that metabolic rate, especially if I have a bariatric patient with they’re eating less, but then they also start exercising more.

The Solution: Proper Nutrition and Metabolic Reset

(28:37):

Now they’re really in a deficit and really creating this metabolic mess because you are one not going to be able to sustain muscle mass, your body’s going to start using that muscle, which is the opposite of what you want because you’re going to lose your metabolic power. In a study entitled Metabolic Determinants of weight gain in Humans, researchers investigated the relationship between metabolic factors and weight gain. Those who are metabolically thrifty or are more likely to gain weight than those who are metabolically spin thrift as their resting metabolic rate is lower and their energy intake is less responsive to changes in energy intake in addition to burning fewer calories at rest metabolically thrifty individuals are less likely to increase their calorie expenditure when they overeat. In addition, the study found that people who are undereating are more likely to have difficulty losing weight as a result of undereating.

Body can burn less fat and its resting metabolic rate may decrease

(29:51):

The body can burn less fat and its resting metabolic rate may decrease. So this study suggested that metabolic factors contribute to weight gain and weight loss resistance. It’s more difficult to lose weight for people who are metabolically thrifty and who undereat. They also found that weight loss resistance is more likely to occur in people. Who undereat and as a result of undereating. The resting metabolic rate and fat burning ability of the body decrease according to one study. Metabolic adaptations during negative energy balance or undereating, and their potential impact on appetite and food intake examines how metabolic adaptations can affect appetite and food intake during negative energy balance. If your total energy and protein intake are equalized, sustained negative energy balance, results in weight loss and body composition changes that are similar to those in different dietary interventions. So what is the solution? Basically kind of a metabolic reset.

Consult a Registered Dietitian

(31:04):

So after bariatric surgery, overcoming weight loss resistance. Really does involve providing your body with necessary nutrition and signaling of metabolism that is safe to lose excess weight. So here are some recommendations. One, this is where you’ll want to work with a bariatric dietitian and making sure that you are having these conversations of calories and undereating and understanding that, hey, maybe I do need to eat a little bit more but you need to work with someone who understands this and that you can do it well because you can’t just go from eating 900 calories a day to 1900 calories a day without a lot of consequences. So this is where working with someone who understands how to do this correctly. So if that is you, I would happy to work with you in making sure that. You are getting adequate energy intake and no longer undereating.

Focus on Nutrient-Dense Foods

(32:17):

Number two, just really focus on nutrient dense food. Just getting the essentials in, getting your proteins, getting the healthy fats, getting the vegetables and fruits and whole grains, making sure you’re getting a balance that it’s sustainable. It’s not just a short-term temporary diet. This is something that you can do lifelong. Number three, get adequate protein intake. I would say I probably do this the most at really helping people hit their protein goals consistently. And that’s the key. You have to fuel your body and it takes time. It’s not going to just flip that metabolic switch overnight, and that’s where you have to be patient with the process and. Keep working through the areas that contribute to weight loss resistance. Number four, balanced calorie intake. So again, making sure that you’re getting the nutrients that your body needs and that it’s sustainable. Number five, moving your body.

Conclusion

(33:25):

Just getting regular physical activity is important for lifelong health. So you don’t want to be extreme where you have to maintain this crazy workout. You need it to be something sustainable that makes sense for your life. And then of course, getting adequate hydration. So all of this stuff plays a role in everything functioning appropriately. So let’s wrap this up. Hopefully with this information, it’s allowed you to kind of reflect and. Say maybe I am undereating and kind of messing with my metabolic rate and my overall metabolism. And maybe that’s why I’m struggling with weight loss resistance. And if this is you, I would encourage you to reach out. I would love to help you work through this and figure out how much you really do need to consume and. What it is that is getting you hung up in this weight loss resistance state. Sometimes it’s truly just adding a hundred calories here, a hundred calories there of the right type of calories. Do you need it in protein? Do you need it in carbs, fats, what does your body need? What is it lacking? I hope this helps you look through the lens of your intake that less is not more. And the more that you restrict your calories, the increase in risk of messing with your metabolic rate can occur. So I hope that you’ve enjoyed this and. I hope that you’ll reach out if you need any assistance in determining if undereating is a cause of your weight loss resistance. So you guys have a great week and we’ll talk to you next time. Bye-bye.

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