“When we taste sugar, the body starts reacting the moment sweetness touches the tongue,” says Dawn Menning, a registered dietitian who works with health app Nutu. “The brain recognises it as a quick source of energy and activates the reward system, releasing the feelgood chemical dopamine that makes it so appealing.” Interestingly, not everyone tastes sugar in exactly the same way – in 2015, researchers compared different types of siblings’ perception of sugar and sweeteners, and found that identical twins were more similar to each other in their sweet taste perception than fraternal twins or non-twin siblings. They concluded that genetic factors account for about 30% of the variance in how sensitive people are to sweet tastes – but it’s unclear whether that actually affects how much we eat.