Washington: Researchers have found that in addition to recognising sweet, sour, salty, savoury, and bitter tastes, the human tongue can also pick up on carbohydrates - the nutrients that break down into sugar and form our main source of energy.

The finding may explain both why diet products are often viewed as not being as satisfying as their real counterparts and why carbohydrate-loaded drinks seem to immediately perk up athletes - even before their bodies can convert the carbs to energy.