Babies that are breastfed are far more likely to eat well and stay fit through childhood than bottle-fed infants, a landmark study showed yesterday.

The Growing Up In Scotland survey, commissioned by the Scottish Government in 2003 and updated this week, found a "significant" link between breastfeeding in infancy and a healthy body mass index (BMI) in later childhood.

More than one third (34%) of non-breastfed children suffered from a poor diet, according to the study, compared to just 16% of breastfed babies. Similarly, 17% of breastfed babies had a "good" diet while just 7% of non-breastfed ate well, the study showed.

The study also found that nearly one in five (19%) of non-breastfed babies would go on to eat not a single vegetable on a typical day.

Researchers said there was a definite link between breastfeeding and diet, but added that there may be other factors to consider. The report said: "The association between diet in childhood and breastfeeding history is clear.

"However, this does not explain if being breastfed is the sole cause of differences in diet or if there are other characteristics which make a mother both more likely to breastfeed and more likely to feed her child healthier foods."

One likely explanation was that wealthier mothers were more likely to breastfeed their babies than poorer parents were, and the study consistently found better diets and higher levels of physical activity among children in more affluent households.

However, researchers also wrote: "It is interesting to note that differences between breastfed and non-breastfed children persist, even when isolated by socio-economic classification or income group."

Children's minister Adam Ingram voiced concern at the inequalities highlighted in the report, and vowed to fight these problems in government.

"Such trends form part of the wider, deep-rooted social problems in Scotland such as poverty, poor health and lack of opportunity, which we are tackling head-on through the early years framework," he said.