What role do fitness gels and chews play in endurance sports?

Why Fitness Gels and Chews Are Helpful for Endurance Sports

Fitness gels and chews provide a concentrated, easily digestible source of carbohydrates (30-60g/hour) that maintains blood glucose levels, delays fatigue, and improves endurance performance during prolonged exercise lasting longer than 1 hour, while minimizing gastrointestinal discomfort compared to solid foods. 1

Primary Mechanisms of Benefit

Fuel Delivery During Exercise

• Carbohydrate gels and chews maintain blood glucose levels during prolonged exercise, preventing the depletion of muscle and liver glycogen stores that would otherwise lead to fatigue 1, 2
• The American College of Sports Medicine specifically recommends consuming 30-60g of carbohydrates during endurance events lasting longer than 1 hour 1
• All carbohydrate supplement forms (gels, chews, drinks) are equally effective at maintaining blood glucose and improving performance compared to water alone 2

Practical Advantages Over Whole Foods

Gels and chews offer superior portability and reduced gastrointestinal burden compared to solid foods during intense exercise 1, 3:

• Carbohydrate bars significantly reduce peak power output (-3.9%) and increase nausea, stomach fullness, and abdominal cramping compared to gels, making bars a less favorable option during intense endurance performance 3
• Sports foods like gels minimize gastrointestinal issues that athletes fear or experience during competition, which often limits their carbohydrate intake 1
• The compact, easily transportable nature of gels and chews allows athletes to meet the 30-60g/hour recommendation without carrying voluminous quantities of whole foods 4

Central Nervous System Effects

Beyond simple fuel provision, carbohydrates consumed during exercise activate oral cavity receptors that reduce perceived effort and improve motor output 1:

• Carbohydrate mouth rinsing alone has been shown to increase self-selected jogging speed and sprint performance during intermittent exercise 1
• The benefits of carbohydrate ingestion extend to improved shooting performance, dribbling speed, and passing accuracy in sports like football 1
• However, athletes should swallow the carbohydrate-containing fluid after mouth exposure rather than spitting it out, as this allows both central nervous system activation and actual fuel delivery to occur simultaneously 1

Optimal Implementation Strategy

Timing and Dosing

• Consume approximately 30-60g of carbohydrates per hour during events lasting longer than 1 hour 1, 5
• For match-based sports, consume ~30-60g after warm-up and again at half-time to meet hourly guidelines within the constraints of competition rules 1
• Utilize stoppages during competition for additional intake when athletes have increased carbohydrate or fluid needs, particularly in hot conditions 1

Product Selection Considerations

Not all gels are created equal—osmolality varies dramatically (303-10,135 mmol/kg) among commercial products, which has major implications for gastrointestinal comfort and fluid requirements 6:

• Gels with higher osmolality require greater fluid intake to optimize carbohydrate delivery and prevent gastrointestinal distress 6
• Products containing multiple transportable carbohydrates (fructose and maltodextrin) may enhance absorption rates 3
• Choose products that have undergone third-party testing, as 15-25% of sports supplements may contain undeclared prohibited substances 5

Important Caveats and Pitfalls

Gastrointestinal Tolerance

While gels are generally better tolerated than solid foods, some athletes still experience gastrointestinal discomfort with gel consumption 7:

• In one study of long-distance triathletes, 7 out of 9 participants reported gastrointestinal discomfort with gels versus zero with liquid carbohydrates 7
• The extreme variation in gel osmolality (4424 ± 2883 mmol/kg) means some products are more likely to cause problems than others 6
• Athletes must practice with their chosen products during training before implementing them in competition 4

Hydration Coordination

• Gels and chews must be consumed with adequate fluid to optimize gastric emptying and prevent gastrointestinal issues 1, 6
• Hypertonic fluids containing both carbohydrates and sodium improve water absorption efficiency during endurance events 1
• Athletes should aim to lose no more than 2-3% of body weight during races lasting longer than 1.5 hours 1, 5

Pre-Competition Fiber Management

Athletes should avoid high-fiber foods in the hours before training and competition to reduce gastrointestinal discomfort risk, making low-fiber gels and chews particularly valuable in the immediate pre-exercise and during-exercise windows 1:

• A low-fiber diet for 48-72 hours before major endurance events can reduce gastrointestinal discomfort and the need for bowel movements on race day 1
• This strategy is commonly employed by Tour de France cyclists, marathon runners, and Ironman triathletes 1

Performance Evidence

Multiple studies demonstrate that carbohydrate gels and chews produce faster time trial performances compared to water-only conditions 2:

• 10-km cycling time trials were significantly faster with all carbohydrate supplement types (17.2-17.3 minutes) compared to water alone (17.8 minutes) 2
• The performance benefits appear equivalent whether carbohydrates are delivered via sports beans, gels, or drinks, as long as the total carbohydrate dose is matched 2
• The key factor is meeting the 30-60g/hour carbohydrate target, not the specific delivery format, though gels offer practical advantages during intense exercise 1, 2