Dana Lis PhD: New Research on Gluten-Free and Low-FODMAP Diets For Athletes, and Takeaways For Your Needs

March 8, 2017


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Dana Lis, PhD, is a Registered Dietitian, researcher, lifetime athlete and has a huge knowledge base on sports nutrition for optimizing athletic performance. Dana’s been involved in current research examining gluten-free and low-FODMAP diets for athletes, especially endurance athletes, which is the focus of this episode. You can reach Dana at www.summitsportsnutrition.com or on Twitter: @dlisforrest.

Intro & Why Our Guts Are At Risk

  • Dana’s background and how she got involved in this area of research.
  • The research shows perhaps we need to think twice about gluten as the cause of GI issues, and perhaps look more to FODMAPs as the problem.
  • FODMAPs = Fermentable Oligosaccharides, Disaccharides, Monosaccharides and Polyols.
  • “Available literature suggests that it is the reduced fructan and GOS quantity in a gluten-free diet that modulates GI symptoms and not gluten itself (Gibson and Muir 2013; Gibson et al. 2015).”
  • The Monash FODMAP app and online resources
  • Why does endurance exercise run the risk of causing gut issues (a refresher) and can we train ourselves to have a stronger gut?
    • Takes 4 to 5 days for epithelial cells (the gut) to repair after a bout of endurance exercise; but athletes train more frequently than that.
    • Increased intestinal permeability from exercise may lead to excessive absorption of gluten-derived peptides in NCGS, which could lead to immune-related responses.
    • Dehydration and heat further compromise intestinal integrity.
    • Altered digestion of short-chain carbohydrates may augment GI symptoms triggered during exercise.
    • Despite some GI-adaptions in trained individuals, splanchnic blood flow is still reduced by up to 80% at 70% V02max (Qamar & Read, 1987).
  • How common are GI issues? “Gastrointestinal (GI) symptoms are common in up to 70% of endurance athletes (de Oliveira & Burini, 2009), and aside from mechanical, psychological and physiological triggers, several dietary factors are believed to influence symptoms (de Oliveira et al., 2014).”

Gluten Research on Athletes

  • Takeaways from the review article: “Commercial Hype Versus Reality: Our Current Scientific Understanding of Gluten and Athletic Performance.”
  • “This diet has not been shown to affect either positive or negative competitive performance or symptoms of GI health and inflammation and/or nutritional status in NCA (non-celiac athletes).”
  • But, in NCA, what if a GFD (gluten-free diet) makes someone feel better even if the science says “no difference?”
  • What about athletes with subclinical conditions and reports showing how gluten increases inflammation, intestinal permeability, leaky gut and so on?
  • “Exploring the Popularity, Experiences, and Beliefs Surrounding Gluten-Free Diets (GFD) in Non-Celiac Athletes (NCA)” show positive outcomes with a GFD, even if the placebo effect aka “belief effect” is at play.
    • 910 athletes
    • 59% follow a GFD less than 50% of the time (GFD < 50).
    • 41.2% follow a GFD 50–100% of the time (GFD > 50), including 18-world and/or Olympic medalists. Predominantly endurance sport athletes.
    • 84% of the GFD > 50 group indicated symptom improvement with gluten removal.
    • Reasons why athletes adopted this diet (self-diagnosed vs medical condition); risks of the diet; positive outcomes reported; and conclusions.
  • Meanwhile Dana’s study, “No Effects of a Short-Term Gluten-Free Diet on Performance in Non-Celiac Athletes” showed no difference and no positive effects of a GFD in healthy well-trained athletes.
    • How this study was conducted and outcomes.
    • Was the intervention possibly not long enough to see an effect?
    • What did the GFD consist of and how did you control to make sure athletes didn’t know as well as control for adequate calories and carbs.
  • Are there really any downsides to going gluten-free especially if you’re able to ensure proper calories, carbs, etc.
  • Perhaps a better approach for pre-competition special diets may be a low-residue diet, especially to hit race weight goals and attenuate any potential gut distress.
  • On being cautious of “orthorexic” behavior towards food and special diets like GDF and low-FODMAP.

Low-FODMAPs for Athletes

  • While gluten and GFDs are pretty well known and trendy, FODMAPs seem to just be getting more attention in the athletic community.
  • Will low-FODMAP diest be the “next big thing?” They already are Down Under, with low-FODMAP foods labeled on shelves of stores.
  • What’s the potential negative issue with FODMAP foods and why these foods could be even more risky for athletes than gluten alone?
    • “Fructans and other FODMAPs are poorly absorbed in the small intestine where they increase luminal fluid content and possibly affect gastric motility. Poorly absorbed, they subsequently transit to the colon as products for fermentation by colonic bacteria, resulting in GI symptoms such as diarrhea and flatulence. Although no data are published yet in athletes without IBS, it is conceivable that residual FODMAPs in the small intestine (ileum) and colon or intake of FODMAPs during training potentiates GI distress during and after strenuous exercise.”
  • So maybe it’s not the gluten, it’s the FODMAPs!?
    • “Available literature suggests that it is the reduced fructan and GOS quantity in a gluten-free diet that modulates GI symptoms and not gluten itself (Gibson and Muir 2013; Gibson et al. 2015).”
  • Is gluten is technically a FODMAP?
    • Gluten is a protein in wheat, barley, and rye. Gluten and fructans are not the same thing. Fructans are a type of carbohydrate in these same foods (and more). Research is hinting that perhaps it is the fructans (a type of carb) in these foods, not the gluten that is causing the issues in people!
  • What are some common FODMAP foods sports nutrition supplements/products.
  • Dana’s case study on 31 y/o male multisport athlete with a history of exercise-induced GI symptoms especially in running:
    • Single-blinded approach; 6-day habitual diet compared to a 6-day low FODMAP intervention diet (81 ± 5g vs 7.2 ± 5.7g FODMAPs.day-1) for their effect on GI symptoms and perceptual wellbeing. Training was similar.
    • Symptom improvement with low FODMAP diet prior to and throughout 3 d of strenuous running training. “Although there are limitations associated with self-report data, these initial findings from our group suggest that perceived gluten-triggered GI symptoms in athletes might be due to FODMAPs, particularly fructans and lactose as potential symptom modulators.”
    • His statement: “symptoms were remarkably better compared to habitual period and were basically non-existent during exercise or during the day throughout the intervention period.”
  • In the case study, what did his low-FODMAP diet consist of and how did you control to make sure he didn’t know?
  • Based on research, what FODMAPs appear to be biggest offenders and why?
    • Fructans, lactose, and fructose.
    • Fructose may be incompletely absorbed and causes bloating, abdominal pain/discomfort, and flatulence. Fructose combined with glucose can be problematic too.
    • Lactose was the most common trigger reported in Dana’s survey (86.5%, n = 402 of 465, of the 92.8% attributing high FODMAP foods to GI symptoms); yet, it is so commonly consumed by athletes, including whey protein powders.
    • Lactose and gluten combines were most frequently attributed to GI symptoms by 52.7% (n = 245 of 465).
  • Thoughts on adopting a low-FODMAP diet? Do arbitrarily or only if a condition present
  • Should we test the state of our gut health as well, in order to partake in a healing protocol to build back a stronger gut?
    • IBS, SIBO, Candida, leaky gut, etc., are all seemingly becoming more widespread in athletes and non-athletes with all sorts of side effects. Should we be weary of these foods to begin with if training (i.e. gluten, FODMAPs), or wait until there’s a problem whether clinical or subclinical?
  • Training the gut to handle the sports nutrition you need.
  • How often should you do training sessions to build a strong gut and during which sessions
    • Only necessary once a week – do it during your “big” key session each week (long ride, long run or long brick).
  • Low-FODMAP sports nutrition sources.


  • Closing thoughts on special diets and how to make use of this information for your own sports nutrition needs.


  1. Lis D, Stellingwerff T, Shing CM, Ahuja KD, Fell J. Exploring the popularity, experiences and beliefs surrounding gluten-free diets in non-celiac athletes. Int J Sport Nutr Exerc Metab. 2014; 25:37–45.
  2. Lis D, Stellingwerff T, Kitic CM, et al. No effects of a short-term gluten-free diet on performance in non-celiac athletes. Med. Sci. Sports Exerc. 2015b; 47:2563-70.
  3. Lis D; Fell J, Ahuja K, Kitic CM, Stellingwerff T. Nutrition and Ergogenic Aids. Volume 15 & Number 4 & July/August 2016
  4. Lis D, Ahuja KDK, Stellingwerff T, Kitic CM, Fell J. Case Study: Utilizing a Low FODMAP Diet to Combat Exercise-Induced Gastrointestinal Symptoms. International Journal of Sport Nutrition and Exercise Metabolism. 2016; http://dx.doi.org/10.1123/ijsnem.2015-0293.
  5. Lis D, Ahuja KDK, Stellingwerff T, Kitic CM, Fell J. Food Avoidance in Athletes: FODMAP Foods on the list. Appl. Physiol. Nutr. Metab. 41: 1002–1004 (2016); dx.doi.org/10.1139/apnm-2015-0428.
  6. Pfeiffer B, Stellingwerff T, Hodgson AB, et al. Nutritional intake and gastrointestinal problems during competitive endurance events 
(Med Sci Sports Exerc. 2012;44(2):344–51.
  7. Soares FL, de Oliveira Matoso R, Teixeira LG, et al. Gluten-free diet reduces adiposity, inflammation and insulin resistance associated with the induction of PPAR-alpha and PPAR-gamma expression. J Nutr Biochem. 2013;24(6):1105–11.
  8. Uhde M, Ajamian M, Caio G, et al. Intestinal cell damage and systemic immune activation in individuals reporting sensitivity to wheat in the absence of coeliac disease. Gut
  9. Halson SL, Martin DT. Lying to win—Placebos in sport science. Int J Sports Physiol Perform. 2013;9:597–9. 
  10. Hadjivassiliou, M., Sanders, D.S., Grunewald, R.A., Wood- roofe, N., Boscolo, S., & Aeschlimann, D. (2010). Gluten sensitivity: from gut to brain. The Lancet. Neurology, 9, 318–330. PubMed doi:10.1016/S1474-4422(09)70290-X.
  11. Loucks, A.B. (2004). Energy balance and body composition in sports and exercise. Journal of Sports Sciences, 22, 1–14. PubMed doi:10.1080/0264041031000140518
  12. Despain, D. 2014. The surprising reason gluten-free diets actually work. [Online.] Available from outsideonline.com/1923951/surprising-reason-gluten-free-diets-actually-work.
  13. Golley, S., Corsini, N., Topping, D., Morell, M., and Mohr, P. 2015. Motivations for avoiding wheat consumption in Australia: results from a population survey. Public Health Nutr. 18: 490–499. doi:10.1017/S1368980014000652.


One Comment

  • eimearrose says:

    Really interesting podcast. I'm currently being investigated for celiac disease (awaiting confirmatory biopsy). I have always had weird gut issues, even before I became an endurance athlete, but symptoms worsened as I became more active. I was advised to try low FODMAP and low residue diets, and of course, they work even for celiacs because a lot of the symptoms of celiac disease relate to malabsorption in the small intestine, leaving a lot of undigested food entering the colon, causing diarrhoea, gas and bloating. However, what really raised the flag was the development of other issues, anemia, vitamin D deficiency and osteopenia (and I've had two weird stress fractures, pubic ramus and fibula). I think it's safe to say that IBS and intolerance to FODMAPs shouldn't cause malabsorption, whereas celiac disease might be a possible cause and might even seem to improve a bit on low FODMAP/low residue diet, so if anyone else has IBS symptoms *and* symptoms of malabsorption/deficiencies, it's worth getting investigated for celiac disease. Due to reduced surface area for absorption, it's also probably true that a low FODMAP/low residue diet would be helpful for celiacs in the early days post diagnosis, to reduce symptoms while the gut heals.

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