Topic
Every study covered on this subject, newest first.
Twenty four healthy adults took nitrate rich or nitrate stripped beetroot, with and without caffeine. Caffeine alone raised two measures of arterial stiffness. Taken together with the nitrate rich drink, those measures sat at placebo levels.
Food and Function · McLellan et al. · Loughborough University · 25 August 2026 · PMID 42639731
Sixteen advanced resistance trained men lifted and jumped under capsaicin, placebo and no supplement at all. All three conditions came out the same. The third arm was there to catch a belief effect, and it did not find one.
Nutrition and Health · de et al. · Paulista University · 20 August 2026 · PMID 42623016
A meta-analysis pooled 11 cross sectional studies covering 1006 athletes, about half of them classified as having low energy availability. The classified group differed on body composition, bone density Z score and cortisol. Leptin showed no significant difference, and because every study measured everything at one moment, none of it establishes cause.
European Journal of Clinical · Han et al. · Yongin University · 19 August 2026 · PMID 42618779
A modified starch that releases short chain fatty acids in the colon lowered markers of intestinal barrier damage during 90 minutes of cycling. Muscle glycogen and 5 km time trial performance were untouched.
The Journal of Physiology, · Karl et al. · U.S. Army Research Institute of Environmental Medicine · 11 August 2026 · PMID 42581384
Twenty six men and women did ten days of fixed workload exercise in a hot chamber. They adapted in all the usual ways, running cooler with lower heart rates and more sweat. But blood plasma volume held steady and maximal oxygen uptake did not move, which are the two changes heat training is often expected to deliver.
American Journal of Physiology, · Greenfield et al. · US Army Research Institute of Environmental Medicine · 7 August 2026 · PMID 42566767
A conference presentation citing Gatorade Sports Science Institute data reported that 50% of female athletes surveyed consumed zero carbohydrate during training, 43% started workouts already underhydrated, and only 20% replaced sodium losses afterwards. None of the figures can yet be checked against a method section.
Badshah et al. · 4 August 2026
Sixty grams of maltodextrin during hard intervals cut muscle glycogen use by about 40 percent and left the liver untouched. Adding caffeine and four other actives cancelled the sparing, because the riders simply went harder.
American Journal of Physiology · Hannon et al. · Manchester Metropolitan University · 4 August 2026 · PMID 42552237
Trained cyclists who finished a 160 minute ride 2.8% of body mass down oxidized about 16% less of the glucose they drank than when fully hydrated, with no change in gut comfort or gut barrier stress markers.
Journal of Applied Physiology · Macrae et al. · 1 August 2026 · PMID 42420769
A systematic review of 91 sodium bicarbonate supplementation studies found GI symptoms rising dose dependently from 0.2 to 0.5 g/kg, and identified four promising mitigation strategies, none of which has been compared head to head.
European Journal of Sport · Winter et al. · undefined August 2026 · PMID 42499192
In a randomized crossover of 13 physically active young men, 800 mg of nitrate from beetroot juice improved peak torque and power by roughly 3 to 4% at two of three tested speeds. Isokinetic strength, not endurance performance.
Nutrients 18(14):2377 · 31 July 2026
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
Pooling 26 crossover trials in female team sport athletes, caffeine produced a small edge in sprinting, jumping and change of direction, and made hard efforts feel easier. Skill based and cognitive outcomes showed nothing reliable, and no dose, timing or format pattern held up.
Nutrients · Li et al. · Henan Sport University · 24 July 2026 · PMID 42588052
Endurance trained men who took a ketone monoester alongside caffeine before 90 minutes of loaded walking in the heat lasted 8.9 minutes in a following run to exhaustion, against 7.0 minutes on an energy matched carbohydrate drink, and held their accuracy on the easier of two working memory tasks. Core temperature and heart rate were the same either way.
Journal of the International · Lints et al. · University of South Carolina · 16 July 2026 · PMID 42460838
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
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
In a double blind crossover of 12 healthy adults doing four hours of simulated occupational heat stress, a 55% fructose sports drink and a matched sucrose drink produced the same rise in a kidney stress marker. A useful null on the fructose side of multi carbohydrate fueling, from a June paper.
American Journal of Physiology · Tourula et al. · 16 June 2026 · PMID 42302737
Nine well trained female cyclists were emptied of glycogen and then fed either a great deal of carbohydrate or almost none for the next day. Power at the first ventilatory threshold fell by nineteen watts, and gross cycling efficiency fell with it. The all out sprint at the end was unaffected.
European Journal of Applied · Main et al. · the Auckland University of Technology · 2 June 2026 · PMID 42228164
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
A major review, From Metabolism to Medals, revisits contemporary carbohydrate guidelines for fueling endurance athletes during exercise, written by an author list that spans the field's main carbohydrate research groups.
Journal of Nutrition 156(5) · Morton et al. · undefined May 2026 · PMID 41759826
Thirty nine adults with type 2 diabetes did six weeks of twenty hours fasting and six weeks of their usual life, in random order. The weight came off through a large reported calorie deficit. Leptin fell, fasting ghrelin rose, and the gut peptides did not move.
International Journal of Obesity · Kramer et al. · the Leadership Sinai Centre for Diabetes at Mount Sinai Hospital and the University of Toronto · 11 March 2026 · PMID 41814085
The only quantitative meta analysis of carbohydrate loading protocols pooled 30 studies and then tested which parts of the protocol predicted the size of the glycogen overshoot. Two variables mattered and four did not, and one of the four was maximal oxygen uptake.
Frontiers in Physiology 16:1620943 · Solem et al. · the Norwegian School of Sport Sciences · 18 August 2025 · PMID 40901614
Seventeen well trained lifters, eight weeks of supervised training, both arms ten percent above maintenance at 2.2 grams of protein per kilogram, and intake statistically matched. The fasting arm did fewer repetitions, rated its daily energy lower, and gained about four kilograms less on the squat.
Journal of the International · Blake et al. · the Center for Sport Performance at California State University Fullerton · 16 April 2025 · PMID 40241374
A personalized carbohydrate test produced individual doses of 49 to 80 g per hour, averaging about 65, that matched the oxidation achieved by a generic 90 g per hour protocol with 28 percent less carbohydrate, lower perceived effort and less stomach fullness, as reported by the University of Birmingham.
Performance Nutrition 1:2 · Podlogar et al. · 9 April 2025
Thirteen world class race walkers spent five to six days on a ketogenic or a high carbohydrate diet, then everyone ate a full carbohydrate day and raced. The retooling arrived in under a week. It did not leave in a day. Carbohydrate oxidation came back to 61 and 78 percent of where it started.
The Journal of Physiology · Burke et al. · the Australian Catholic University · 19 August 2020 · PMID 32697366
Twenty nine elite race walkers trained hard for three weeks on one of three controlled diets. The ketogenic arm reached fat oxidation rates higher than any previously published. It also needed more oxygen to walk at race pace, and it was the only arm that did not improve its ten kilometre time.
The Journal of Physiology · Burke et al. · the Australian Institute of Sport · 14 February 2017 · PMID 28012184
Seven cyclists ate the same food in two different orders around an evening interval session. Going to bed with the carbohydrate already spent raised the fat side of the programme by morning, including a shift in DNA methylation. It did not raise the markers of mitochondrial building the practice is usually sold on.
Journal of Applied Physiology · Lane et al. · RMIT University · 25 June 2015 · PMID 26112242
Seven cyclists trained for five days on either a high fat or a high carbohydrate diet, then ate a full carbohydrate day. Muscle glycogen ended up identical. Pyruvate dehydrogenase activity did not. After the fat week it was lower at rest and throughout exercise, and glycogen was broken down more slowly.
American Journal of Physiology, · Stellingwerff et al. · the University of Guelph · 27 September 2005 · PMID 16188909
Seven men emptied their muscle glycogen with exhausting exercise, then ate either almost no carbohydrate or a great deal of it for two days. The high carbohydrate arm raised the glucose transporter message and lowered the message for the brake on burning carbohydrate. The low carbohydrate arm did the reverse on the fat side.
American Journal of Physiology, · Arkinstall et al. · RMIT University · 3 February 2004 · PMID 14761878
Twenty five men were put through either a depletion protocol or a taper only protocol and then fed identically for six days, with muscle glycogen measured every day by magnetic resonance. On day five the two protocols were level. On day seven the depletion group pulled ahead.
American Journal of Physiology, · Goforth et al. · the Naval Health Research Center · 5 August 2003 · PMID 12902321
Fourteen trained cyclists ate five days of high fat and five days of high carbohydrate in a crossover. Resting muscle taken after the fat diet carried more of the message for the main fatty acid transporter, and more of the transporter protein itself.
The American Journal of · Cameron-Smith et al. · Deakin University · 1 February 2003 · PMID 12540388
Eight endurance trained men ate 10 grams of high glycaemic index carbohydrate per kilogram a day and did no training. Muscle glycogen roughly doubled within 24 hours and then stopped moving, and every fibre type had already reached its ceiling.
European Journal of Applied · Bussau et al. · the University of Western Australia · 28 May 2002 · PMID 12111292
An earlier trial had reported that women could not supercompensate muscle glycogen at all. When carbohydrate was prescribed per kilogram of lean body mass instead of as a share of habitual energy intake, women loaded as well as men.
European Journal of Applied · James et al. · the University of Western Australia · 1 October 2001 · PMID 11718281
Seven well trained cyclists rode a 100 kilometre time trial twice, once after carbohydrate loading and once after a placebo controlled moderate carbohydrate diet, eating carbohydrate during both rides. Loading raised muscle glycogen significantly and did not change the time.
Journal of Applied Physiology · Burke et al. · the Australian Institute of Sport · 1 April 2000 · PMID 10749820
Five well trained cyclists ate four weeks of a ketogenic diet with calories held constant. Glucose oxidation fell threefold, muscle glycogen use fell fourfold, and endurance time at a moderate pace was unchanged. This is the study the whole low carbohydrate argument in endurance sport is built on.
Metabolism 32(8):769 to 776 · Phinney et al. · 1 August 1983 · PMID 6865776
Trained runners went through three exercise and diet regimens before a 20.9 kilometre run. The classical severe depletion arm and a moderate carbohydrate arm reached the same muscle glycogen, and no arm produced a faster run.
International Journal of Sports · Sherman et al. · 1 May 1981 · PMID 7333741
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