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In this issue

• Randomised double blind crossover Published 13 May 2026, verified on PubMed. The paper drew press attention in late July. Cite the May date.

  Glucose plus fructose kept its oxidation edge even in underfueled athletes

  In a double blind crossover trial, a 2:1 glucose to fructose blend oxidized more of the ingested carbohydrate than glucose alone, and the advantage held after 48 hours on half energy intake. Better oxidation did not rescue performance after the deficit.

  The Journal of Nutrition · Barney et al. · 13 May 2026 · PMID 42134413

  carbohydrateendurance-fuelingenergy-availability
  0.48g/min

  exogenous carbohydrate oxidation with the 2:1 blend vs 0.39 g/min with glucose alone, p<0.001
• Commentary with a systematic evaluation of study designs Date verified

  Only 2 of 14 carb loading studies were properly blinded, and both found nothing

  A systematic evaluation of the carbohydrate loading performance literature found that only two of fourteen studies were double blind and placebo controlled. Both of those also fuelled athletes during exercise, and neither found a performance benefit.

  International Journal of Sport · Jones et al. · Liverpool John Moores University · 24 June 2026 · PMID 42342234

  carbohydrateendurance-fuelingresearch-methods
  2of 14

  carb loading performance studies were double blind and placebo controlled, and both found no benefit
• Expert opinion (Current Opinion article) Date as listed in the digest; not independently verified at source.

  Low FODMAP diets are being handed to athletes who may not need them

  A Current Opinion in Sports Medicine argues that symptom severity, not habit, should decide whether an athlete restricts FODMAPs. Athletes with mild or occasional symptoms are likely better served by a more liberal FODMAP intake that supports gut integrity.

  Sports Medicine · Scrivin et al. · 24 July 2026 · PMID 42496856

  gut-healthGI-distressfodmapfiberendurance-fueling
  0trials pooled

  expert opinion arguing FODMAP restriction should match symptom severity, not be a default
• Human feeding study 27 July 2026 is the date of the Cornell Chronicle story; the journal publication date is not stated in the digest and was not verified at source.

  Whether fiber helps may hinge on which strain of one gut bacterium you carry

  Cornell researchers fed resistant starch to more than 50 people and sequenced their microbiomes at strain level. Different strains of the same species, Bifidobacterium adolescentis, responded to the identical fiber in opposite directions.

  Microbiology Spectrum · Poole et al. · 27 July 2026

  microbiomefibergut-health
  >50people

  fed resistant starch; strains of one bacterial species responded in opposite directions
• Convergent mixed methods, observational Published July 2026. The journal issue carries no day of the month.

  Only about a quarter of women at the IRONMAN Worlds hit carb loading targets

  Among female triathletes at the 2024 IRONMAN World Championships, 6 of 23 reached the 8 to 12 g/kg carbohydrate loading guideline, with a mean intake of 6.4 g/kg. Interviews found the shortfall was not a knowledge gap.

  European Journal of Sport · Fortis et al. · Liverpool John Moores University · 1 July 2026 · PMID 42274547

  carbohydrateendurance-fuelingfemale-athletesGI-distress
  26%

  of these athletes, 6 of 23, met the 8 to 12 g/kg guideline. Mean intake was 6.4 g/kg
• Narrative review Date as listed in the digest; not independently verified at source.

  Four nutrition claims aimed at active women outrun their evidence

  A narrative review examined four claims circulating on social media about female athlete nutrition. It found limited evidence behind several of them, but not for the rigid sex specific rules built on top of them.

  Proceedings of the Nutrition · Matkin-Hussey et al. · 1 July 2026 · PMID 42383324

  female-athletesgeneral-nutritionenergy-availability
  4claims

  examined; limited evidence for several, none for the rigid rules built on them
• In vitro screen plus narrative review The digest lists 16 and 22 July 2026 for the two papers; dates taken from the digest and not verified at source.

  Two new looks at sweeteners and the gut, and neither delivers a clean verdict

  An in vitro screen found around 75% of 39 sweeteners altered the growth of at least one of 25 gut bacterial species. A separate narrative review concluded the evidence supports neither a uniformly harmful nor a uniformly safe verdict on artificial sweeteners.

  Molecular Systems Biology (screen); · Xin et al. · 16 July 2026 · PMID 42514471

  sweetenersmicrobiomegut-healthgeneral-nutrition
  ~75%

  of 39 sweeteners altered growth in at least one of 25 gut bacterial species, in vitro
• Narrative review Date verified

  Microplastics reach athlete diets, but nobody has studied athletes directly

  A narrative review raises dietary microplastic exposure in athletes, flagging packaged foods and bottled drinks as plausible exposure routes. The authors are explicit that mechanisms are plausible while direct studies in athletes do not exist.

  Nutrients 18(14):2398 · 22 July 2026 · PMID 42514468

  microplasticsgeneral-nutrition
  0studies

  direct studies of microplastic exposure in athletes exist to date, per the review