Researchers never stop studying the effects of out-of-home care on very young children, and that is just as well, since governments in many countries are encouraging mothers to farm out their little ones while they go to work. Research results are mixed; some find a link between daycare and better knowledge and language skills (though not always); others find increased levels of stress in young children, and a tendency to aggressive behaviour as the children get older.
The French-Canadian province of Quebec has a big stake in this information because 15 years ago it rolled out a province-wide, $7 a day childcare scheme which was aimed at helping the poorest children, as well as make it possible for women to stay in the workforce and have babies and thus lift a dangerously low fertility rate. You can read here what one commentator had to say about the fiscal results early this year.
Reports on how the kids are doing are mixed. The latest, from researchers at the University of Montreal, is negative. It reveals that children aged between 4 years and 10 are 50 percent more likely to be overweight if they attended a daycare centre between the ages of 18 months and four years, compared with those care for at home by their parents. Even leaving a child with a relative significantly increased the risk of obesity, the Daily Mail reports.
The study did not nail down the reasons, although it controlled for some known risk factors for obesity, said lead author Dr Marie-Claude Geoffroy:

'This difference cannot be explained by known risk factors such as socio-economic status of the parents, breastfeeding, body mass index of the mother, or employment status of the mother.' The chief suspects are fairly obvious:

'Diet and physical activity are avenues to follow,' says Dr Sylvana Côté, who co-directed the study, published in the Journal of Pediatrics. People from the New Zealand childcare industry were quick to say it would not be their fault, and that many kids ate better at daycare than at home. One mother suggested that children in childcare might face weight problems was because of stressed parents trying to cook something easy for their children.
Still, it’s just possible, isn’t it? that daycare staff might be stressed, too, and take the easy way out with a fussy child -- by giving them more of what they want and less of what they should eat. The same would apply to ensuring that each child is active enough. And that is not something that a tired working mum is going to insist on at the end of the day, either.
Ultimately, though, it’s the parents’ responsibility, one of the research team points out:

'Parents don't have to worry; however, I suggest to parents they ensure their children eat well and get enough physical activity, whether at home or at daycare.' Of course, that is going to be hard when there is only one parent at home. In A Quebec Family Portrait published last year, the Institute for Marriage and Family, Canada, noted that 63.1 percent of children in the province were born outside of marriage in 2010 -- many outside of cohabiting relationships also.
The government is trying to fill the gaps -- but at huge cost to taxpaying families and to Quebec’s fiscal health. It has one of the highest debt-to-GDP ratios in the world. And the IMFC report said that a single income family in Quebec with two children between the ages of six and 17 earning $60,000 annually in 2010 would have had a tax bill of $15,437, compared to $12,429 in Ontario and $11,193 in Alberta. What that’s doing for the birthrate, goodness knows.