Adam Peaty

It hasn't always been a sweet ride. When I was 15, I almost hated racing in finals because I was so nervous. But as I got more experienced, I had to choose between fight and flight - and I've fought every time.

In a Harvard University study, the diets of nearly 1,000 women were analysed before their morning melatonin levels were measured. Meat consumption was the only food significantly associated with lower melatonin production, for reasons that are as yet unknown.