David Cameron and Nick Clegg have met with families after pledging up to £1,200 a year in government support for children.
The Prime Minister described the funding as effectively "some tax relief on childcare".
"For many families the cost of childcare is not one issue among many, it is the issue - it really matters," Mr Cameron said.
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Youngsters are still consuming too much unnecessary sugar and caffeine, according to the study.
Home Office data offers an incomplete picture of the perpetrators and victims, the National Audit Office (NAO) have said.
The report concludes that nine million adults suffer from constant loneliness, which is as harmful to health as obesity or smoking.