Carb-only bottle

A carb-only bottle is a separate drink that contains a concentrated source of carbohydrates with little or no electrolytes. It is used alongside water or an electrolyte beverage to meet high carbohydrate requirements without taking in excessive fluid.

Purpose and benefits

Endurance athletes sometimes need 60–90 grams of carbohydrate per hour to sustain energy, which can be difficult to achieve using standard sports drinks without overhydrating. A carb-only bottle allows athletes to increase carbohydrate intake by sipping a denser mixture of sugars while still controlling fluid and sodium intake through another bottle. Typically, the carb bottle contains a blend of glucose, maltodextrin and fructose at a concentration of 12–20% in water. Because it is more concentrated than a typical 6–8% sports drink, it should be consumed in small sips and followed with plain water or electrolyte drink to maintain appropriate osmolality and prevent stomach upset. This strategy also enables separate adjustment of carbohydrate and electrolyte intake based on individual needs and environmental conditions.

Using a carb bottle

To prepare a carb-only bottle, dissolve about 80‑100 grams of carbohydrate powder per 500 millilitres of water. Common combinations include 2:1 ratios of glucose or maltodextrin to fructose to utilise multiple intestinal transporters. Label the bottle clearly and take small sips every 15–20 minutes during long events while also drinking water or a standard carbohydrate–electrolyte beverage to stay hydrated and replace sodium. Monitor how your stomach feels and adjust the concentration or sip rate if you experience bloating. Athletes sometimes alternate sips between their carb bottle and plain water or use gels and chews for some of their carbohydrate. After the session, rinse bottles thoroughly to prevent residue.

A carb-only bottle helps athletes meet high carbohydrate targets without forcing large volumes of fluid. When paired with an appropriate hydration plan, it can support endurance performance and energy levels.

Related Terms: Scheduled drinking, Multiple transportable carbohydrates, Maltodextrin, Dextrose, Salt capsules