*Their scrumptious flavour and lush texture are misleading: gram for gram, sweet potatoes have about the same number of kilojoules as white potatoes.
*Studies have shown that high doses of beta-carotene supplements may be harmful to smokers, but there's no evidence that a diet rich in sweet potatoes, carrots and other natural beta-carotene sources can be anything other than beneficial.
*In fact, a group of American researchers experimented on themselves by eating a high-carotenoid lunch every day for three weeks. They choose sweet potatoes as their source – and eating just 170g per day raised their plasma levels of beta-carotene by more than 100 per cent.