GLP-1 Drugs and Nutrition Gaps: Douglas Kalman, PhD, Explains the Companion Nutrition Opportunity

Ahead of Nutritional Outlook's second annual The Outlook on Active Nutrition, managing editor Sebastian Krawiec interviews Douglas Kalman, PhD, RD, co-founder of the International Society of Sports Nutrition and Substantiation Sciences, clinical associate professor at Nova Southeastern University's Dr. Kiran C. Patel College of Osteopathic Medicine, and program chair of Nutritional Outlook's upcoming The Outlook on Active Nutrition conference.

Dr. Kalman breaks down why GLP-1 medications, which can drive 5–15% body weight loss, often push users into calorie intakes as low as 800–1,000 calories a day — far too little to meet baseline needs for vitamins, minerals, fiber, essential amino acids, and essential fatty acids. That nutrient gap, he explains, has opened a real and growing "companion nutrition" market, one already visible on major U.S. drugstore shelves. He also discusses the loss of muscle mass that frequently accompanies GLP-1-driven weight loss, the overlap with the fitness and sports nutrition communities, and an often-overlooked risk factor: dampened hydration due to reduced thirst cues.

Dr. Kalman also reflects on last year's inaugural The Outlook on Active Nutrition conference and previews what attendees can expect this year, where he'll lead a session on formulating for muscle preservation in the GLP-1 era.

Learn more and register for the conference here.

Transcript

Sebastian Krawiec: Hi everyone. My name is Sebastian Krawiec. I am joined today by Douglas Kalman, who is a co-founder of the International Society of Sports Nutrition as well as Substantiation Sciences. He is also a clinical associate professor at the Dr. Kiran C. Patel College of Osteopathic Medicine at the Nova Southeastern University in Fort Lauderdale, Florida. Dr. Kalman is also the program chair of our upcoming conference, The Outlook on Active Nutrition, and we thank you so much for joining us today.

Douglas Kalman: Thank you so much for having me, Sebastian. I remember and recall with great enthusiasm being excited and then attending the 2025 Outlook on Active Nutrition conference, and one of the reasons that I was so excited about it is that the event really allows for great topics, interaction with the audience, and networking. And I felt that for every individual speaker that was there, the way that the hotel was set up, the way that the educational rooms are set up, allowed for great notetaking, great listening, even again being able to say, Excuse me, can you repeat what you're saying, and it was beautiful.

And one of the things that I observed was interactions, of course, in between people that know each other already, but more importantly, people that did not know each other already, and maybe working within the same aspects of industry or different aspects of industry, and getting to know more people, allowing for the networking, you know, of spending your day with a group of people learning, you know, builds new relationships. And I just thought that the Outlook on Active Nutrition, last year's conference, was so well organized, you know, with a beautiful lunch with everybody together and breakout sessions and more, that it just made me that much more motivated to say, Hey, can I be involved in this year's Active Outlook on Nutrition? Because more and more of society, besides hearing about the health of being active, is actually trying to take some type of action for their own health, and active nutrition helps sometimes motivate those people that are not yet active to then join the active crowd and continue their journey of health.

Krawiec: Well, thank you so much for the kind words. It was it was exciting to really have that inaugural conference. It was the first time we've ever done a live event, and we're very happy with the outcome and the feedback that we received. So it's heartening to continue hearing this lovely feedback, and you know, we're really looking forward to having people back in New Jersey for this next conference, and hopefully, you know, continue to deliver on that promise that we established.

And in addition to you being program chair, you're also going to be speaking about kind of the GLP-1 companion market and, you know, formulating for muscle preservation. I wonder if you can kind of give us a small primer about, you know, that session and how active nutrition brands can help GLP-1 users. Why is this a relevant market to really be cornering?

Kalman: Well, one of the things to really understand is that nutrition is central to health, and one of the poor things in medicine, if you will, is that when you would go to your physician for your yearly checkup, your annual physical, if you will, one of the things that the physicians would note when they write their progress note, their assessment, would be something that's called they would look at you. They may or may not put you on a scale and check your height, weight, body mass index, but they would use the initials WDWN, well-developed, well-nourished, which is really a, you know which is really a moniker for more than adequate weight on this person. And in medicine and public health, nobody was really looking at health as a weight as a biomarker. Even though we know that your body weight has a role in risks of a variety of diseases, and with obesity, it could be type 2 diabetes, it could be changes in cognitive health, cardiovascular health, and so much more.

Now, the GLP-1 receptor antagonist market, or GLP-1, these are a class of medicines and that have been around for about 20 years, but now are really making it to market and newer versions, long time in drug development, that really seem to have an impact on body weight. We're talking anywhere from 5 to 15% of body weight loss, but in that body weight loss, we also have loss of muscle and other things of concern. So, when it comes to weight loss, these medicines work in part by reducing appetite, reducing the want to take in food, and by imparting some feelings of satiety when you do eat. So the person that's on as, just a popular name a Wegovy or a Zepbound, not endorsements, just naming something popular, is that they are now taking in less calories, and calories in versus calories out, if you have less in, then you know, you you're going to lose weight, right? So, what's happening though is the medications are strong, and they do induce, you know, reduction in appetite, want to eat, food cravings, what people call food noise, right? And people that are on the medicines are then following something that's equivalent to a very low-calorie diet or a low-calorie diet, like 800 to 1,000 calories, which just, by definition, in and of itself, you're not going to get enough nutrient density to meet your vitamins, minerals, fiber, essential amino acids, essential fatty acids and so forth needs in 1,000 or 800 calories a day. So there's a great nutrient gaps that are known, defined, observed, that are occurring in people on these classes of medicines that allows an entrée for the dietary supplement world to say, Hey, let us be your adjunct to health while you're using a prescription medicine for weight loss, because you want to do it in the healthiest way. So if you're on these medicines and you're not even taking a multivitamin mineral, you're automatically, you know, you're missing out on whole slew of vitamins, minerals, fiber, essential amino acids.

So there is a real need for companion nutrition, if you will, not talking about dogs. That's a different companion nutrition market. But companion to medical care and medical intervention. So this GLP-1 adjacent market or support market is very real. I walked in one of the major one of the major drug store chains in the United States and the first thing you see that coming in was, We have GLP-1 nutrition support products. And, you know, then there was a whole row of them. And they're not the only chain in America doing that. So I'm, and as a registered dietitian, without doubt, people that are on GLP-1 receptor antagonists do need specialized nutrition help to make up these gaps and to help reduce the amount of side effects that does occur as related to the medications.

Krawiec: Obviously GLP-1 act receptor agonists have been kind of also hyped for other benefits and kind of there's a sort of like this biohacking movement of people utilizing these drugs for a variety of reasons. Do you think that there will also be kind of an will be or is already an embrace of these drugs in like the fitness and bodybuilding communities to for these variety of other benefits?

Kalman: I will tell you this. Part of my history has been as a, or is as a sports nutritionist. I've worked 6 Olympic games, worked with a number of professional sports and athletes. I've had professional athletes that operate in weight-based sports ask me my thoughts on for them using these medicines during fight camp or during some other camp to help make weight. So, which tells me everybody has an interest, not just somebody that's looking for obesity reduction or reduction of risk of diabetes and so forth. I think that, you know, that was a great question.

Krawiec: Is there anything surprising about, you know, the nutrition that's overlooked among GLP-1 users?

Kalman: You know, one of the things that happens when we talk about nutrition for somebody on medication, GLP-1 as an example, is we do think about vitamins, minerals, fiber, protein, essential amino acids, essential fats, and some other stuff. But we also forget that if you're not hydrated, hydration is really important. And one of the impacts also, when you're eating less because you have less appetite, you have less thirst. So, I'm trying to say that we also, it's another great reason to promote hydration products and to that person that's on that, because automatically they have dampened intake. So hydration is often overlooked as something that's important for health in this way.

Krawiec: Well, thanks so much, Dr. Kalman. This has been a great conversation, and we really look forward to, you know, having you at the show and seeing everyone at the show, and it's going to be fun.