Low Carb Diets and Energy Expenditure During Weight Loss Maintenance

Mark Labriola: Welcome to Obesity: A Disease, the official Obesity Medicine Association podcast exploring the many facets of the disease of obesity. In this series of podcasts, we have carefully selected recent articles included in the latest version of the OMA Obesity Algorithm. We then discuss this new science with obesity experts. I'm Mark Labriola, and in this episode, OMA Chief Science Officer Dr Harold Bays interviews Karli Burridge about the effects of a low carb diet on energy expenditure during weight loss maintenance. Obesity: A Disease podcast is brought to you by the Obesity Medicine Association, the clinical leader in Obesity Medicine.

Harold Bays: We are fortunate to have with us today, Karli Burridge. Karli, before we get started, can you tell the folks who you are and what you do?

Karli Burridge: Absolutely. First of all thank you so much for having me today. I'm very excited to be on the podcast.

HB: Great to have you.

KB: I'm an obesity medicine specialist. I'm a physician assistant, and I'm currently the Director of weight management services at Lifeway Bariatrics in Downers Grove, IL near Chicago. I just started with them a few months ago. I'm going to be developing their medical weight management program in conjunction to their bariatric surgery program so that we can offer comprehensive obesity management solutions for anybody struggling with weight.

HB: Well then you're absolutely the perfect person today. Because today we are going to talk about a study that was published by Ebbeling in the British Medical Journal in 2018. It's entitled “Effects of a Low Carbohydrate Diet on Energy Expenditure During Weight Loss Maintenance.” I found it to be very interesting. I think we talked about this before we got on air; this was a very popular article, and you're the podcast speaker who got it. (A lot of people had a very high interest.) What these researchers did was they had people that had lost weight with the appropriate nutrition and such. Afterwards, they stratified people based upon carbohydrate content. They had high carbohydrate content and moderate carbohydrate content and low carbohydrate content. What they found is that lowering the dietary carbohydrate maintained higher energy expenditure during weight loss maintenance. And they felt like this may have implications as to how we can help patients, not just with weight loss, but with weight loss maintenance. What's your general overall sense when you read this article and you thought about how it may have implications for the patients that you manage?

KB: Well the first thing that I thought about is hope. This research article gives us hope because we know that to lose weight, we can do that lots of different ways. But weight maintenance is where we really struggle because we know the biologic adaptations that happened with weight loss. We know that energy expenditure or metabolism goes down with weight loss. We saw that with some of the studies like The Biggest Loser study and things like that. We know that ghrelin levels or hunger hormone levels go up and our satiety hormones go down. And so I think in weight maintenance that's one of the biggest things we struggle with are those biologic adaptations that occur with non-surgical weight loss. With surgical weight loss, we see the opposite, right? We often see a decrease in hunger hormones, increase in satiety hormones, and we don't see that shift in metabolism that we do with non-surgical weight loss. So that's one of our biggest hurdles when it comes to long-term weight management. How do we overcome that? What I really liked about this article is it gives us some insight into how we might be able to overcome or offset some of those biologic adaptations. And I like that they looked at energy expenditure; their findings were very eye-opening. Patients who had the highest insulin levels at baseline had the biggest improvements in their energy expenditure. So they stratified their patients into thirds as far as their insulin secretion, and they found those patients with the highest insulin levels had about a 400-calorie greater energy expenditure on the lowest carbohydrate diet. So I think that tells us a lot about individualization of nutrition plans as well, and that we need to be looking at things like their insulin levels when we're putting them on a nutrition plan. And then also that there's hope that some of these biological adaptations that occur, that we can overcome them, perhaps with a completely natural treatment strategy like a nutrition plan. It's not a medication. It's something that we can offer all our patients. I think it offers us hope to overcome those biological adaptations with weight loss.

HB:I guess what I'm hearing from you is what we try to do is fight biology with biology. There's always been this concept out there about this thing, this mysterious thing called a leptin resistance. I'm talking about central nervous system leptin resistance where there's this diminished effectiveness of hyperleptinemia (in reducing appetite) that you get with the increase in leptin levels due to increase in body fat. This is similar to diminished CNS effectiveness of increased insulin levels in a patient with insulin resistance, that also occurs with increasing body fat. Neither work on the brain like they should.

KB: Right.

HB: And so in the past the way that we've tried to manage that is we get people engaged in physical activity. At least for me, one of the most effective answers to a question: “What are the types of things that you can do to help with weight loss maintenance?” is “routine physical exercise.” It may not necessarily help a lot with weight reduction; but regular physical exercise does helps with weight loss maintenance. What I'm hearing from you is maybe this (lower carbohydrate intake) is number one or two on the list.

KB: Absolutely, and I think that's what's so exciting because I'm a big proponent physical activity and that we should be active. You know I've spoken on the topic before and I have a background in that. I think it's important for all of us to be active. But to ask a patient or anyone to have to exercise 60 to 90 minutes a day to keep their weight off, that's very hard for people to do. That's hard for anyone to find the time to do that. Those recommendations are based on lowering of metabolism and reduced energy expenditure with weight loss. This is something we need to do more research. But (alternatively or concurrently) perhaps if you had a different nutrition plan, a lower carb nutrition plan, you may not need to exercise 60 to 90 minutes a day to keep that weight off. Because if you're looking at a difference of energy expenditure of 400 a day, well that's like doing an hour of physical activity. That's like walking or running 4 miles a day. So it might be an opportunity where you could say, “Okay well you have options, right?” If you prefer a higher carbohydrate diet, then maybe you need to do these higher levels of activity. Or if you say that you have a difficult time fitting that into your lifestyle, then maybe you can follow a lower carb nutrition plan and you don't need to do as much physical activity. And again, these are just possibilities. But this is where we need to do more research and I could see that potentially as an implication of this study.

HB: Well, I think it goes to what you said at the very beginning when you talked about if you get folks that have the hyperinsulinemia, their insulin levels are high—insulin's a growth factor.

KB: Right.

HB: Insulin also sort of shuts down lipolysis from fat cells and such. Isn't it interesting that the two things you can do that can help with weight loss maintenance (physical activity and low carbohydrate nutritional intake) are two things which seem to drive down insulin levels? Isn't that what you were saying at the beginning?

KB: Yes, and I think that insulin plays a huge factor in this. And actually, the relationship of insulin with lipolysis, that really got me thinking about many years ago back when I was studying clinical exercise physiology in grad school. That was the “aha” moment of me. We saw a graph of insulin levels and lipolysis. What you saw very clearly that as insulin levels go up, lipolysis goes down, and lipogenesis goes up. And at the time I had gained about 30 pounds in college and was figuring out how I could lose that weight. I tried every diet under the sun. They were all low-fat approaches and they weren't working for me. And so for me, it was an “aha” moment for myself, and I tried (a low carbohydrate diet), and it worked for me. But it was that first recognition that maybe insulin plays an important role in all of this.

HB: And this happened when? How long ago was this?

KB: That was in 2005.

HB: Well, you should have talked to these research folks. They could have published this a lot sooner. What you're saying is you personally found out on your own through your own life experience - kind of what this article has now proven scientifically. Am I hearing that correctly?

KB: That is absolutely correct. That is what was so interesting to me. At the time back in 2005, you didn't hear a lot about this. There wasn't a lot of research that I was aware of about this. And so it's really exciting that now, fast forward many years later. Now we're seeing all this research and it kind of validates kind of what I was thinking back then. Yeah, it's really neat to see it kind of come full circle and to see the research being done.

HB: And look, I mean, I'm not with you when you manage patients. But I'm guessing you take what you know scientifically, and you take from what you've been trained, and you take what you know personally and you apply these principles to the care of patients. is that correct?

KB: That is correct. I check a fasting insulin level on all of my patients. I calculate their HOMA 2 insulin resistance score and I base their nutrition plan on a lot of that information. I think it's very helpful for patients to see those numbers when you're talking to them about a nutrition plan. Because then it makes sense to them, what you're asking them to do or what you would you agree upon to do with that patient. I think we need to give patients options. There's not one nutrition plan that works for everyone. But if patients have a better understanding of why you might be suggesting one nutrition plan over another, or what the benefits might be one nutrition plan versus another nutrition plan, then they are better able to make an educated decision about which path they'd like to go.

HB: And that's a patient-centered approach, isn't it?

KB: Absolutely.

HB: Okay, well thank you very much, Karli. Thank you for being with us.

ML: Thank you, Dr Bays and Miss Burridge. For more information about Obesity Medicine Podcasts and other resources from the clinical leader in obesity medicine, please visit obesitymedicine.org/podcasts. Love this episode of Obesity: A Disease? Head over to iTunes to subscribe, rate, or leave a review. The views expressed in this podcast episode are those of the show hosts and do not necessarily represent the opinions, beliefs, or policies of the Obesity Medicine Association or its members. Please check back soon for another episode of Obesity: A Disease.

Disclosure Statement: Unless noted, all individuals in control of content reported no relevant financial relationships.

Credit Renewal Date: July 31, 2021