Children who drink full-fat milk weigh less than those who drank semi-skimmed milk, a study at the University of Toronto has found.
Doctors found that children who drank whole milk were about a kilogram lighter than those who drank the 1 per cent fat variety.
Scientists argue that children should be encouraged to drink whole milk instead because it may make them feel fuller and reduce the amount of sugary and fatty food they eat.
Jonathon Maguire, a scientist at St Michael’s Hospital in Toronto, noticed that child obesity rates had trebled over 30 years in North America while whole milk consumption halved over the same period.
He wondered whether this might be more than coincidence. Dr Maguire and his colleagues signed up 2745 Canadian children between the ages of two and six to see if there was any link between their weight, their vitamin D levels and the kind of milk they drank. They asked parents whether they gave the children full-fat, 2 per cent, 1 per cent or skimmed milk, as well as taking blood samples for chemical analysis.
On average the children drank about two cups of milk a day. Half of them were routinely given whole milk, while a third drank 2 per cent milk and most of the remainder were given 1 per cent.
The results, published in the American Journal of Public Health, suggest that children fed full-fat milk were less than half as likely to be overweight and less than a third as likely to be obese as their peers who were on a diet of 1 per cent milk.
This held true even after the researchers corrected the data for factors such as exercise, screen time and sugary drink consumption.
Dr Maguire believes that children will on the whole regulate the calories they consume according to how full they feel. This means that when their parents give them lower-fat milk, they may satisfy their hunger with less healthy foods.
It is, however, also possible that the phenomenon could be caused by parents who notice that their children are getting a little fat and switch them to a lower-fat milk to help them to lose weight.
Dr Maguire called on health authorities to encourage parents to give their children whole milk.
“[The advice] warrants closer examination,” he said. “We really do want to make sure that what whatever guidelines we have around milk consumption are achieving the ends they were created to achieve, and if they’re not, or if they’re even causing the opposite to happen, then that needs to be reconsidered.
“Cow’s milk is something that more or less every child consumes and it surprises me that we don’t know the answer to what the best type of milk they should be drinking is. That sounds like something we really should be pushing for.”