Apple Puree as a Natural Fructose Source Provides an Effective Alternative to Artificial Fructose Sources for Fuelling Endurance Cycling Performance in Males

Carbohydrate consumption during exercise enhances endurance performance. A food-focused approach may offer an alternative, ‘healthier’ approach given the potential health concerns associated with artificial fructose sources, but food-based carbohydrate sources may increase gastrointestinal (GI) symptoms. This study compared the cycling performance and GI comfort of two different fructose sources (fruit and artificial) ingested during exercise. Nine trained male cyclists (age 24 ± 7 years; VO2peak 65 ± 6 mL/kg/min) completed a familiarisation and two experimental trials (60 g/h carbohydrate, 120 min at 55% Wmax and ~15 min time trial). In the two experimental trials, carbohydrate was ingested in a 2:1 glucose-to-fructose ratio, with fructose provided as artificial crystalline fructose (GLU/FRU) or natural apple puree (APPLE PUREE) and maltodextrin added to provide sufficient glucose. Time trial (TT) performance was not different between trials (GLU/FRU 792 ± 68 s, APPLE PUREE 800 ± 65 s; p = 0.313). No GI symptoms were significantly different between trials (p ≥ 0.085). Heart rate, blood glucose/lactate concentrations, and RPE were not different between trials, but all, excluding blood glucose concentration, increased from rest to exercise and further increased post-TT. Apple puree as a natural fructose source provides an alternative to artificial fructose sources without influencing cycling performance or GI symptoms

Apple puree as a natural fructose source provides an effective alternative carbohydrate source for fuelling half-marathon running performance

Carbohydrate supplementation during endurance exercise is known to improve performance, but the effects of food-based approaches in running exercise are understudied. Therefore, this study investigated the performance and gastrointestinal (GI) effects of a carbohydrate supplement containing a natural fructose source compared with a highly processed fructose source in a combined glucose-fructose supplement, during a half-marathon. Eleven trained runners (9 males, 2 females; age 32 ± 8 y, 89:53 ± 13:28 min half-marathon personal record) completed a familiarisation (8 miles) and two experimental trials (13.1 miles) on an outdoor running course, with blood and urine samples collected before and after the run. Subjective GI measures were made throughout the run. Carbohydrate was provided as a natural fructose source in the form of apple puree (AP) or highly processed crystalline fructose (GF) in a 2:1 glucose-to-fructose ratio (additional required glucose was provided through maltodextrin). Half-marathon performance was not different between carbohydrate sources (AP 89:52 ± 09:33 min, GF 88:44 ± 10:09 min; P = 0.684). There were no interaction effects for GI comfort (P = 0.305) or other GI symptoms (P ≥ 0.211). There were no differences between carbohydrate sources in ad libitum fluid intake (AP 409 ± 206 mL; GF 294 ± 149 mL; P = 0.094) or any other urinary (P ≥ 0.724), blood-based (P ≥ 0.215) or subjective (P ≥ 0.421) measures. Apple puree as a natural fructose source was equivalent to crystalline fructose in supporting half-marathon running performance without increasing GI symptoms.  Highlights: Research examining food-first and food-based approaches to carbohydrate supplementation and endurance running performance are limited. Therefore, this study aimed to compare carbohydrate supplements either containing a natural or highly processed fructose source as part of a glucose-fructose supplement on half-marathon running performance and gastrointestinal comfort in trained runners. Running performance (apple puree 89:52 ± 09:33 min vs. crystalline fructose 88:44 ± 10:09 min), gastrointestinal comfort and symptoms were not different between the two fructose sources. Apple puree can be effectively used as a carbohydrate source to fuel half-marathon running performance.</p