Big breakfast 'could boost fertility' As a result, it could increase the chance of people with Polycystic Ovary Syndrome (PCOS), a menstrual problem which affects 6-10 per cent of women of childbearing age, being able to have children, researchers said. Each of the patients was told to eat about 1,800 calories per day, slightly below the recommended daily total for women, but with half having their main meal of the day at breakfast and the other half at dinner. The findings, published in the Clinical Science journal, found that there were higher levels of ovulation in the group who ate their largest meal, typically measuring about 980 calories, in the morning. Among the "big breakfast" group, glucose levels and insulin resistance decreased by eight per cent while levels of the androgen testosterone dropped by 50 per cent, while there was no change in those who ate their larger meal at dinner time. Prof Oren Froy, who led the study, said: "The research clearly demonstrates that indeed the amount of calories we consume daily is very important, but the timing as to when we consume them is even more important." Edited for telegraph.co.uk by Nick Collins