Progress in tackling bulging waistlines among primary one pupils has stagnated in the last decade, as 22.1 per cent of children had an unhealthy body mass index (BMI) in 2015/16 school year compared to 22.3 per cent in 2006/7.
Campaigners warned that childhood obesity was “a ticking timebomb”, linked to serious health concerns such as cancer, diabetes and heart disease.
It comes after public health experts suggested that school pupils should be weighed to curb rising obesity levels.
Calls have been made to tackle multi-buy offers and junk food sales in supermarkets as well as marketing and advertising of unhealthy food.
Lorraine Tulloch, programme lead at Obesity Action Scotland, said: “It is all too easy to become complacent about this repetitive message on obesity but we all need to understand that childhood obesity is a ticking timebomb of health problems.
“This situation can no longer continue. If the Scottish Government is serious about increasing the proportion of children of healthy weight then they must take immediate action to support families to make the healthy choice the easy choice.”
The issue is most acute in deprived areas, as only 73 per cent of the poorest children are a healthy weight compared to 81 per cent in richer areas.
Professor Linda Bauld, a cancer prevention expert at Stirling University, said: “The fact that so many children as young as four are entering primary school carrying too much weight is a stark reflection of the obesity epidemic that’s gripping Scotland.
“As part of its new obesity strategy, the Scottish Government can and must now do more, including tackling the barrage of supermarket multi-buy offers on sugar and fat-laden food and drinks.
“Obesity is also linked to 13 types of cancer including bowel, breast and pancreatic. If left unchecked, we run the risk of obesity becoming a crippling burden on society and the NHS.”
The Scottish Government is due to publish a new obesity strategy next year, which could include measures to limit promotions and advertising of junk food.
Public health minister Aileen Campbell said: “We are committed to addressing Scotland’s excess weight and have announced our intention to consult on the development of our new Diet and Obesity Strategy in 2017, building on our wide range of activity to make it easier for people – including children and their families – to be more active, eat less, and eat better.
“We recognise we need a shift in emphasis from dealing with the consequences to tackling the underlying causes, such as ending poverty, fair wages, supporting families and improving our physical and social environments. That’s why we are driving investment in affordable housing and continuing commitments including free prescriptions, concessionary travel and free personal care.”