“There is a lot of confusion and outright falsehoods about fasting. You can search the internet for clarity and end up more confused than when you started.

The fact is, fasting can be a very effective tool to improve your metabolic health, increase insulin sensitivity and help you lose weight. But, who should and shouldn’t use fasting for weight loss and how long to fast for effective weight loss are questions that need to be answered before you rush into fasting.

The main thing to consider is to what end? What’s your why?”

Karla Lester is a pediatrician.

She shares her story and discusses her KevinMD article, “Don’t be in a hurry to fast.”

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Hosted by Kevin Pho, MD, The Podcast by KevinMD shares the stories of the many who intersect with our health care system but are rarely heard from.

Transcript

Kevin Pho: Hi, and welcome to the show, where we share the stories of the many who intersect with our health care system but are rarely heard from. My name is Kevin Pho, founder and editor of KevinMD. Rate and review the show at KevinMD.com/rate. Subscribe at KevinMD.com/follow. Today we welcome back on the show Karla Lester. She’s a pediatrician, and her most recent KevinMD article is “Don’t be in a hurry to fast.” Karla, welcome back to the show.

Karla Lester: Thank you for having me. I appreciate it. And again, all of us physicians are so grateful to you, Kevin, for your incredible platform.

Kevin Pho: Now, for those who get a chance to listen to our first few episodes together, just briefly share your story and journey to where you are.

Karla Lester: Well, like you said, I’m a pediatrician. I’ve been a pediatrician for a long time. I call myself a community pediatrician in all aspects of that word. I think I’ve done everything in the field of pediatrics that you could do. I’m a professionally certified life and weight loss coach. I’m a certified diplomate of the American Board of Obesity Medicine. And I’m also somebody who’s gone through my own life and weight journey and lost 57 pounds, starting in September 2017. I never thought I’d have a weight issue, and I had been addressing the childhood obesity epidemic for almost 20 years of my career. I’ve done basically everything you could do: started a nonprofit, started a clinic, led that clinic, and learned so much. Then, when I had my own weight issue, it was such a helpful journey, and I learned, “Oh, gosh, we’ve gotten it all wrong.”

Within that, I used fasting as one of the tools and learned a lot about it, and it was super helpful to me. As you know, I’m on social media a lot, especially on TikTok. I’ve even written up one of my TikTok studies that I did, posted it on KevinMD, and did a podcast interview with you about it on weight stigma and bias in health care, and I’m really excited about all that work.

But anyway, on social media, there are even amazing registered dietitians and other physicians who really blast fasting as a tool and say that it’s a diet, it’s calorie restriction, it’s just starving yourself. It just seems like there’s so much confusion out there. And I know, as physicians, we get virtually zero training on any of this. So with “Don’t be in a hurry to fast,” the play on words within the article is that it can be an effective and amazing tool, but really know what you’re doing, especially if you’re a physician who hasn’t gone through a weight loss journey or hasn’t used intermittent fasting as a tool to improve your metabolic health. There are a lot of tips. I kind of poured in everything I know about fasting and have learned through my own experience and working with patients.

As a disclaimer, my platform is called IME Community. It’s a life and weight coaching platform that’s all web-based, for teens. So I do not recommend fasting for teens.

Kevin Pho: All right, so let’s talk more about your article and go into more detail about fasting. Before we do that, tell us, what is the information that’s out there? If a typical patient goes on Facebook, Twitter, or TikTok, what kind of information are they inundated with with regard to fasting?

Karla Lester: It’s going to be the extremes, like we have with diet culture or the body positive movement. I’m a huge supporter of the body positive movement, and I’m working really hard to cancel diet culture, but my whole platform is, let’s meet in the middle. You can be body positive and feel great, and in fact, that’s what it takes, self-love, the superpower, and also reach your health goals. So they’re not mutually exclusive things.

So you see the people who are, OK, really fixated on the house, stuck in diet culture, saying, “OK, you can do this fasting.” And there are the Instagram wellness perfection folks who are like, “Oh, here’s what I’m doing,” and they’re cropping their shots, and it’s all fakeness. And then you get the extreme of any intentional weight loss, any intentional improvements in your health. I think that the health system and we as physicians have to take responsibility for why patients feel this way, that there’s really nothing out there that is helpful.

So the other extreme is that fasting is just starving yourself and it’s going to cause harm. And I mean, it’s true that for people who have tried it on their own, without a coach, without a physician who knows what they’re doing, or without a dietitian who’s really knowledgeable about fasting, it can really, especially if you have a history, trigger binge eating disorder and get you into that restrictive space. So it’s kind of the extremes, and there’s not a lot in the middle that’s super helpful, just like everything else.

Kevin Pho: All right, so in your article, you give us some reputable pieces of advice about fasting. Talk more about that.

Karla Lester: Well, for instance, fasting is a great tool. When you look at Dr. Jason Fung’s book The Obesity Code, he really upended the status quo of diet culture and the calories-in, calories-out thinking, and that we should be eating small meals frequently throughout the day.

Look at insulin resistance, which is an incredible adaptation of our bodies to constantly high levels of insulin. Our bodies were not meant to be exposed to that. I mean, our bodies are really efficient with our hormones, so insulin is supposed to have peaks and valleys, and times when we’re not exposed to insulin, so that we can mobilize our fat stores for energy, and that keeps you at your healthy weight set point range, which your body does have.

So he said, obesity is hormonal. It’s not just caloric. You don’t just look at total calories; all calories aren’t created equal. So you have to look at the quality and the composition of the food that you’re eating, so the calories, the what to eat. And then you have to look at the timing of your eating. To address the high levels of insulin, look at what you’re eating. To address the constantly elevated levels of insulin, you have to look at the timing.

Kevin Pho: All right, so let’s go into more detail. If I, as a primary care doctor, wanted to correctly implement fasting into a patient’s plan, what’s the right way to go about that?

Karla Lester: Well, first I would learn. I would read The Obesity Code. I would also read his book The Complete Guide to Fasting. So you just learn more about it and educate yourself.

Then the other thing is, none of us get much training on motivational interviewing, but that’s a way to start, a way to ask open-ended questions, see where your patient is, see what their why is, and know what patients to work with. So if they have insulin resistance, they’re overweight, they have metabolic health issues, and obviously you have their labs, fasting can be added as a tool. Make sure that you tell your patients, “This is a tool, and it’s not meant to be restrictive.” And you need to have a lot of support and follow-up and communication with your patient if you’re going to implement fasting.

The first thing, and I said this in the article and I really experienced this myself, is that most of us who are overweight, and maybe have insulin resistance, are carb-adapted. Our bodies are used to seeing carbohydrate and just using that as our energy source to create ATP, so we’re sugar burners. We’re not used to mobilizing our fat stores for energy. So the first step is to really dial in. I call it dialing in on quality food. OK, so that’s transitioning from eating more of the ultra-processed foods, with refined sugars and processed carbs, trans fats, and salt, which are very addictive and which our brains are conditioned to eat. So this can be tough, but know that it’s transitional, to eating more of a balance of complex carbohydrate, adding in protein and healthy fat every time you’re eating.

It takes 4 to 6 weeks, at least. It took my body longer, I think, to become fat-adapted. People say, “How do you know you’re fat-adapted?” Well, it’s awesome, because you feel better. You can tell your blood sugars are stable. Instead of having tsunamis of hunger waves, you have a little wave, and then it’s like, “Oh, it’s fine.” And you really learn to be what we call an intuitive eater, to have more of a connection to your body and honor your hunger.

Kevin Pho: So you mentioned close follow-up is essential if one were to incorporate fasting as a tool. Give us an idea of what you mean by that.

Karla Lester: Well, I think you need to touch base with people, I mean at least weekly, and have them come in for follow-up visits every month, at least. And if you have a dietitian that insurance will cover, who’s familiar with using fasting and taking a therapeutic carbohydrate reduction approach, you can refer them to that.

I will also tell you, I’m a founding member of the Society of Metabolic Health Practitioners. You can go to the website, thesmhp.org. Those are physicians like me and health care providers who are looking at therapeutic carbohydrate reduction as a means to really reduce insulin resistance and an approach to improve metabolic health. We have clinical guidelines there, so that can be super helpful for physicians, and they can work with their patients on that.

Also, if they’re on medication for, say, diabetes, you really need to follow them very closely and follow their blood sugars, because if they’re going to fast, their blood sugars are going to go down. So it’s probably going to be tapering off those meds.

Kevin Pho: So you mentioned teens as not being one of the demographics that’s appropriate for fasting. What are some other groups for whom fasting also is not appropriate?

Karla Lester: That’s an awesome question. So yeah, teens, and I really think until we have our frontal lobes developed, so maybe even the mid-20s. And our society’s so messed up. We’re all so fat-phobic, with internal biases and restrictive mindset and diet culture and thinking. I really think you have to work on your mindfulness, self-compassion, and canceling diet culture and all its harms from your life before you even consider any sort of intentional weight loss or using fasting as a tool.

Anyone who’s had a history of an eating disorder. Obviously, if you’re a binger, it’s going to create more of an indulgence-restriction mindset. You never want to use fasting as a punishment or restriction. That’ll backfire. That is starvation. So for instance, if you decide to fast, maybe do a 16:8, and it’s your first time doing it, and then you get really hungry and shaky and you need to break your fast, then don’t punish yourself the next day with another fast. Just plan on eating. Just move along. You’re just gathering evidence. There’s nothing going wrong. So the coaching is really helpful for that.

I think that as physicians, we’re just hypercompetitive overachievers, and we’re motivated by our negative self-talk and our inner critics. So if you don’t have the tools of self-compassion, if you haven’t leaned into that in your life, I think that fasting could be harmful.

Kevin Pho: We’re talking to Karla Lester. She’s a pediatrician, and she wrote the KevinMD article “Don’t be in a hurry to fast.” Karla, talk to all the patients who maybe listen to this podcast, and they come across Instagram and see a post about how great intermittent fasting is, or a fasting-related post. What kind of questions should they be asking after they come across this on social media?

Karla Lester: Oh, that’s great. So I think that you have to be mindful. We all have to be mindful of our inputs and our outputs and where we get our information. One thing I’ve been doing is saying, “OK, follow this RD. She’s really awesome.” Or, “Follow this therapist.” “Follow this obesity medicine doc.”

So first of all, be really mindful. If they’re a dietitian, make sure that they’re not a nutritionist, that they’re an actual registered dietitian who’s giving information. Make sure that they have studies, if you say, “Can you direct me to a study?” And I would really look to the American Board of Obesity Medicine if you’re looking for a doctor in your area who you want to connect with, who can give you the tools, because we’re trained, when we take our boards through the ABOM, on all the things that work, like the self-monitoring, the accountability, the tracking, and determining your own measures of success. So that could be really helpful, too.

Kevin Pho: And my final question: What are some of your take-home messages that you want to leave with the KevinMD audience?

Karla Lester: Well, I mean, I think that just like anything else, it’s now time for us as physicians to start being really helpful to our patients and addressing this. We have historically gotten a lot of stuff wrong. We haven’t challenged diet culture; we’ve brought it into our practices. We’ve had a more compliance-based approach with our patients, where we kind of tell them what to do and expect them to change their behavior for us, to feel a certain way about ourselves and our practice of medicine. I think we just need to really recognize that we’ve gotten a lot of it wrong, and we need to lean in, to be curious, to find some tools, and to offer things that can be really helpful and that will really work for our patients.

Kevin Pho: Karla, thank you so much for joining me again and sharing your time and insight.