In this second article going in-depth with the team from First Endurance, we speak with Dr. Luke Bucci, First Endurance's Chief Science Officer. As we discussed in our part 1 article discussing First Endurance's past, present, and future as a business, co-founder and VP of Science Robert Kunz decided to retire. Co-founder Mike Fogarty and former VP of Marketing stepped into the role of CEO and set about rethinking everything about the company and its products. His most significant hire, given First Endurance's long-standing focus on incorporating the latest research into their product line, was Dr. Luke Bucci, who joined in April of 2020. In this interview with Dr. Bucci, we do a deep dive on what is arguably the most important of First Endurance's products - EFS (Electrolyte Fuel System), which is their hydration drink. There were a lot of things that drew me to First Endurance in 2008, but EFS was certainly the most compelling for me as an athlete. I was always someone who preferred to get my calories from liquid nutrition. I've never done solids. And I will basically tolerate gels, though I do not actually like them. So when, with EFS, I was basically able to manage 100% of caloric needs, I was thrilled. I would mix my bottles at higher strength and then just take water and Gatorade on course along with additional bottle pick ups at Special Needs.
EFS has seen significant changes over the years. Mostly with regards to flavor experimentation, but also in terms of core ingredients - which particular starches were used being the most significant. The introduction of EFS Pro, which was designed specifically for ultra-distance racing, was the most notable addition to the product line. The most recent iterations of both EFS - which tends to be sweeter, which matches my own preference of preferring sweetness on short rides - and EFS Pro - where sweetness can become cloying over long sessions - make significant changes to both flavor profiles and overall composition.
I worked incredibly closely with Robert Kunz during the 10 years of my professional triathlon career that I relied on First Endurance. The thing that I loved about working with Robert was that he was both a scientist and an athlete. An avid outdoorsman, I never could quite tell what his truest passion was, though his focus on both sustainable agriculture in his home garden and his continued adventures in the wilderness confirm that it really was both nutrition and adventure. Dr. Bucci is certainly a departure in many ways from that, but I think it was the right choice not to try to find another Robert, if such a thing were even possible. Dr. Bucci's palmares as a scientist are impressive, but I was most impressed by his perspective that he shared near the end of this interview where he states, "Although I am by no means a practicing athlete myself, I have worked with elites for decades, and I listen, observe, and incorporate feedback."
His complete bio, provided by First Endurance, is expectedly superlative, and clearly demonstrates First Endurance's continued commitment to innovation on the back of research. Dr. Bucci is the industry leader in sports nutrition. He is an accomplished author and lecturer, and he holds multiple patents and patent applications on clinical laboratory testing methods and nutritional supplements. He's written four texts, contributed to eleven books, over 35 peer-reviewed research journal articles, 37 abstracts, more than 100 technical journal articles, and has presented hundreds of invited lectures and discussions on a variety of topics around the world. He also served on the United States Olympic Committee as an expert advisor on nutritional supplements.
Dr. Bucci graduated Magna Cum Laude with a PhD in Biomedical Sciences (Biochemistry and Cell Biology), from the University of Texas Health Science Center at Houston, Graduate School of Biomedical Sciences in 1983, followed by a double post-doctoral appointment at the world's largest cancer research center.
While our first article focused largely on my own perspectives of First Endurance as a business, both past and present, for this second article, we'll take more of a standard question-and-answer approach with Dr. Bucci.
Slowtwitch : EFS seems like it forms the foundation of the First Endurance line up. And yet it is also the product that you've arguably changed the most throughout your history. How do you balance innovation with not changing a proven formula?
Dr. Bucci: Correct on both counts! EFS is one of our cornerstone formulas and it has been modified the most often. But that's not by plan; there have just been more advancements in the research literature and technologies that are most ideal for EFS vs other items in our system. We're less worried about maintaining best sellers than we are about finding new ways to improve athletic performance. Sure, EFS was proven, but new research proved that it could be more. That's what differentiates us from a lot of other companies: We're a research-driven company, not a marketing company.
Even with a proven product like EFS, we always upgrade a formula when the scientific research and available technologies justify it. It's why we exist as "we"—I wouldn't have joined First Endurance if this wasn't the fundamental philosophy of the company. We're constantly poring over the latest research and evaluating new innovations, because our only objective is to give serious athletes the best-possible endurance nutrition available.
For example, research into new flavoring technologies opened new doors in taste profiles, but the research also gave us a rough starting point for what kind of flavor/ingredient ratio you need to create the desired response—in this case, an improved flavor. It made a lot more sense to apply this new tech to EFS and EFS-PRO than MultiV simply because there was a minimum effective amount required. Adding a gram of additional ingredients to a 38g scoop of EFS makes a lot more sense than adding 20% more mass to a 5g tablet.
Flavors are always a complex topic. In particular, this was one of the big differentiators with EFS Pro and regular EFS. The Pro versions were a much, much milder flavor. And it also saw the introduction of one of the most loved AND HATED flavors in the cucumber version, which reminded me a lot of the Pepsi vs Coke taste tests. Cucumber tasted like crap, honestly, at the start of a ride. But at five hours in, when it was warm, it was great. How do you balance that initial taste with what you know about changing perceptions? Especially on race day...
Anything with flavor adds an entirely different dimension to product development, and, as a result, is much more complicated and challenging, requiring a lot of testing and retesting to get right. And even then, there's never going to be one flavor that appeals to every athlete's palate.
Plus, like you mentioned, taste fatigue is also an important consideration. What tastes good in the lab or in your first bottle of the day doesn't always taste good when you're five hours into a hard training session or race. Or what tastes awful at first might blossom as the day wears on. That's why we spent a year with prototypes of the new EFS, EFS-PRO, and Liquid Shot field testing a wide variety of variables: duration of session, temperature, elevation, conditions, etc.
We accumulated a ton of athlete feedback and used the input to refine each flavor and version accordingly. Just doing the standard food science taste tests would never work for this application, and this obsessive testing is why EFS has four flavor options and why the flavor and sweetness profiles for EFS-PRO are significantly milder.
Adding single-serve packets to the EFS lineup was also, believe it or not, about taste as much as convenience. Our athletes use 2-7 servings of EFS in each session, 5-6 days/week. That's 40-168 servings/month. Single-serve packets let athletes pack different flavors, mixing up flavor profiles throughout the day as appropriate to their taste. It's critical to offer several flavor and sweetness options to avoid "hate drinking" or to keep athletes drinking, period.
Slowtwitch : The EFS sour watermelon flavor is the best I've ever tried in any sports drink ever. How did you decide on that? Am I alone in my love of this flavor?
Dr. Bucci: We know enough to just let the experts do their jobs when we don't have the expertise, and we get out of the way. That's the case here. Without any guidance or specific asks from us, our flavor specialist designed 10 entirely new flavors that she thought would work well with the new formula.
One of these was Sour Watermelon, and even though we loved it, we didn't know if it would make it through the prototype process. If it had been up to us, we would have never thought of Sour Watermelon, which is just another example of how important it is to be able to move on from "proven" products and processes.
Lemon Lime and Fruit Punch are, and have always been, the most-popular EFS flavors. The data we accumulated during a year of prototype testing, however, showed that Orange Splash and Sour Watermelon were preferred 2:1. Since Sour Watermelon, Orange Splash, Lemon Lime, and Fruit Punch ended up consistently testing better than the other flavors, we moved forward with them. (She also created some other amazing flavors that we're sitting on… for now.)
We think—and your experience backs this up—that Lemon Lime and Fruit Punch are more popular than Sour Watermelon only because those two flavors are the most popular hydration mix flavors in the US, across all brands and flavors. Chosen out of habit. Now that we have single-serve packets available, we're going to include samples of Sour Watermelon and Orange Splash with orders. Once customers have a chance to try the new flavors, we expect the popularity balance to change, even if it doesn't invert outright.
Slowtwitch : A core aspect of EFS has always been the ingredients. It has a ton of electrolytes - still does. But that's also changed over time. Less magnesium (most sports drinks don't even have it, because of the potential for GI distress), for example. How do you figure out this blend, especially knowing that magnesium is high risk but also potentially high reward. EFS was, for a time, the only drink with all five electrolytes (except zinc, which is toxic in excessive quantities). Is that still the case?
Dr. Bucci: Electrolyte science changes with time, research, and feedback from users. We start with the research, of course, but we also carefully chart user experiences, good and bad, to make changes. Since we are a nimble company, we can make changes relatively quickly to keep up with what our users find works the best during the field-testing phase.
As for the research-review phase, the general research consensus on electrolytes is, in a lot of ways, still catching up with EFS. Prevailing conventions in that field have discouraged true scientific innovation. It's a lot of dead horses, well beaten. For example, we know that unwanted side effects with electrolytes in athletes are due to imbalances much more than dose amount. Exercising humans have much more leeway - and need - than sedentary people for handling electrolyte loads without issues.
A deeper dive into the research pool also shows that conventionally maligned electrolytes—especially magnesium and calcium—are not only justified for inclusion, but provide outsized anti-cramping benefits. One of the keys to unlocking their potential is simply using the right kind of each electrolyte. That's easy for sodium, chloride, and potassium, but much trickier for calcium and magnesium. It's critical that you use the right chelates for those two, but if you do, the literature (and our own field testing) supports their benefits.
As for zinc, you are right, because it is not an electrolyte, but a trace mineral, which can be easily acutely toxic. It's used to induce vomiting in ER patients who have swallowed something harmful or poisonous, and it works FAST—50-100mg of elemental zinc does the trick. So we leave it out of EFS, but we do cover all the mineral bases with our MultiV & MultiV-PRO multivitamins as part of the comprehensive, mutually complementary First Endurance system.
Slowtwitch : Okay, so you follow the research where it leads. That's exciting as it offers newness, but it's also a risk. Does the research ever lead nowhere?
Dr. Bucci: Yes. That's why science is fun! We don't set out with a particular result in mind, so the research sometimes does lead us… nowhere. That's true even if we develop a working concept formula, but the idea doesn't pan out when we put it in athletes' bodies while field testing.
What we learn at this level lets us push the limits of endurance performance, though we do sometimes push a concept right off a cliff of irrelevancy. It can be expensive and doesn't always result in a new product, but it's always worth trying and we always learn something valuable—even if the lesson is just that, well, that didn't work.
The only product we haven't upgraded since inception is Ultragen. It's not that we haven't looked at options. We just haven't found anything good enough to justify it. Yet. We're always looking, and it's only a question of when scientific research will advance recovery technology, not if.
Slowtwitch : Besides electrolytes, the particular carbohydrate blend has also been a topic of much change. Where are you at now, for both EFS and EFS Pro?
Dr. Bucci: The primary source of carbohydrates in EFS is maltodextrin while the primary carbohydrate source in EFS-PRO is Cyclic Cluster Dextrin (CCD). I won't dive too deep here, but I will say that EFS's maltodextrin is an efficient, high-speed train of glucose; EFS-PRO's CCD is the most advanced carbohydrate source available.
Slowtwitch : Lastly, there's always been some "secret sauce." At first, it was BCAAs. Are they still present? What else do you add?
Dr. Bucci: Yes, the BCAAs are still there, and so is glutamine, both of which have many overlooked roles in exercise. The "secret sauce" this time around is the addition of two other amino acids, L-theanine in EFS and L-theanine and GABA as PharmaGABA for EFS-PRO. Those inclusions really differentiate EFS and EFS-PRO compared to every other hydration mix.
These two amino acids are neurotransmitter precursors that help support mental toughness during exercise via anti-stress actions. The rationale for each is similar: both calm your brain by balancing out exercise-induced panic to keep you thinking and reacting clearly, even while you're at your limit.
The secret in the sauce is using the right forms of each and using the right mode of administration (read: dose amount and timing). It's all about balance, which is what your brain wants and needs for hard training and racing, especially at those critical moments when you're on the limit, legs screaming to stop, and the ability to maintain control and dig deeper makes all the difference.
Slowtwitch : I've always felt that if people were going to invest in ONE first endurance product, EFS would be the one I'd suggest. Does that match your thinking? Is EFS the onboarding product.
Dr. Bucci: Sort of. EFS makes sense as the point of entry simply because hydration mix is the most-popular category in endurance nutrition, the most-used product among endurance athletes. But our foundational product is actually Optygen. It was our first product, and it embodies the First Endurance product design ethos precisely because it wasn't just another hydration mix. It was something entirely different, something that pushed endurance performance in ways that no other company was—or is—doing. A way to realize untapped potential beyond fueling and cramp prevention.
As for product popularity, we have seen a major shift in purchase behavior over the past year-and-a-half. Since COVID hit, MultiV and MultiV-PRO have made the most significant jumps in our ranking reports finding their way into 80% of orders. It was never like that before, but it makes sense, because we're one of the only companies that offer super-premium multivitamins that have higher levels of ingredients that have been shown to support your immune system (like Beta Glucan), help upper respiratory tracts, and reduce the risk of downtime associated with hard training.
It's a new world we live in. I'm not sure the booming 'immune system' category is going to slow down anytime soon.
Slowtwitch : The introduction of EFS-PRO in 2015 was an interesting decision. The whole idea of EFS was always that it was a "pro" level drink, designed to have everything you needed. I remember the electrolyte comparison graph of it and everything else [see fig. 1]. How did you decide you needed a "pro" version? What do you see as the core differences between it and "regular" EFS?
Dr. Bucci: We found so many new technologies that it warranted offering a "PRO" level hydration mix. There were a lot of discussions, both internally and with customers, and the decision was to keep the current EFS (which is, and always will be amazing) and offer an even higher-end option. It's the same reason we have MultiV and MultiV-PRO and Optygen and OptygenHP.
You mentioned the electrolyte comparison. I included that chart here for reference, and you can see that, yes, EFS does distance the competition. EFS-PRO has even more, though, because it's formulated for the most demanding events in the most punishing, hottest conditions. It's also got the most advanced carbohydrate blend we use, primarily Cyclic Cluster Dextrin (CCD). (Okay, I WILL do a CCD deep dive here.)
CCD, which is really an amylopectin multi-branched cyclic dextrin, is a high-glycemic carbohydrate that has little effect on insulin and does not inhibit fat oxidation. This means athletes can sustain hard efforts through the increased use of fats, which allows them to spare essential glycogen and preserve those emergency energy stores—steady fueling during the event and afterburners in the finale, when everyone else has already burned through their reserves.
At 150mOsm, CCD has the lowest-osmolality of any carbohydrate source available, which tells us it gets from gut to bloodstream fast. It has been clinically shown to have the fastest gastric emptying time of any carbohydrate. It's also 100% soluble in water and won't clump or thicken when mixed, which is a good indication of how it gets emptied fast in the stomach. Low osmolality and superior gastric emptying times mean EFS-PRO gets fuel to muscles even faster than EFS, and it can also be mixed at stronger concentrations without impeding uptake, so it can be tailored to the day's conditions.
Slowtwitch : Anything else from you, Dr. Bucci, about First Endurance now that you've been in this role for over a year?
Dr. Bucci: I am impressed with First Endurance's product upgrade philosophy and constant desire to find the new and radical, to constantly challenge the limits of sports nutrition. NEW FOR IMPROVEMENT, NOT JUST FOR CHANGE. That's why I jumped at the opportunity to join up. Mike and co want to eschew convention and take things to the next level, and there are troves of untapped research that show how it's possible.
We stay on top of the published science, but even that has knowledge gaps and constraints that do not reflect real-life settings, so we continue to push the envelope with empirical evidence gathered through unbiased consideration of real-life data when no published science is available.
FE is nimble enough to stay ahead of the thought curve because we live, breathe, eat & sleep endurance nutrition. We're always proactively looking for ways to help athletes improve. We don't just wait for the next study to come out or for new technologies to become conventional, because that guarantees we'd always be behind the curve.
Although I am by no means a practicing athlete myself, I have worked with elites for decades, and I listen, observe, and incorporate feedback. I have always pushed the envelope, and when enough data is known to support a new direction, I jump on it. I know it's right when I keep asking 'why' and run out of 'whys.' That journey sometimes entails going from populations to whole bodies to organs to tissues to cells to subcellular components to molecules to atoms to quantum physics—it's another edge. It's the whole picture, man!
For more information about EFS, EFS-Pro, and the rest of the First Endurance product line, visit their website at FirstEndurance.com.
