The target will be at the heart of the Scottish Government’s Healthy Weight and Diet being published later this summer.
Ms Sturgeon confirmed that Scotland will press ahead with a radical crackdown on the sale of junk foods to tackle the problem.
This will mean a ban on price-cutting and two-for-one style promotions on sweets, crisps and other foods which are high in salt, fat and sugar.
But food industry leaders in Scotland have warned that the move could “punish” many smaller Scottish firms, struggling to compete with multi-national giants.
Almost a third of Scots youngsters are at risk of being overweight, including 14 per cent who are at risk of being obese.
“Obesity is a serious public health issue which cannot be ignored,” Ms Sturgeon said.
“Evidence shows obese children are likely to stay obese into adulthood and become more likely to suffer health problems such as diabetes and cardiovascular diseases at a younger age.
“Our guiding ambition is to halve child obesity in Scotland by 2030 and we’ll outline in our forthcoming Healthy Weight plan how we will develop the necessary actions to achieve this, and help everybody make healthy choices about food.
“As part of this, we will tackle junk food promotions and the marketing of unhealthy food, such as multi-buys, that encourage overconsumption. To ensure that the steps we take are proportionate and deliver beneficial outcomes, we will consult widely with consumers, suppliers and retailers following the release of the new plan.”
An extension of existing advertising curbs on foods high in salt, fat and sugar were among the other measures set out in the recent diet and healthy weight consultation. This could see a ban on junk food ads near schools or hubs where children gather, as well as on buses, trains and transport hubs.
The use of weight loss programmes, including “interventions” by nurses, GPs and social workers, could also be stepped up if they deem a youngster’s weight to be a concern.
But David Thomson, chief executive of Food and Drink Federation (FDF) Scotland said people are already adopting healthier diets.
He said: “We are disappointed that the Scottish Government continues to talk about legislating to restrict food and drink promotions and advertising.
“Our members take their role in tacking obesity very seriously and have made great strides in helping people make healthier choices. Over the past five years our members have reduced calories in the average shopping basket by 5.5 per cent and sugars by 12.1 per cent - this progress made by industry is demonstrated in our new report Feeding Change.
“Instead of punishing Scottish businesses we would urge the Scottish Government to work in partnership with the food and drink manufacturing industry to make a real difference to the health of the Scottish people.”
The SNP leader met the campaigner and chef Oliver to discuss joint action to tackle unhealthy eating.
He said: “First Minister Nicola Sturgeon has shown she cares about the health of Scotland’s kids by committing to halving childhood obesity in the next 12 years. We look forward to seeing her strong multi-layered strategy.”
The move has also been welcomed by doctors leaders in Scotland. BMA Scotland Dr Peter Bennie said more action is needed to address the issue in Scotland.
“A target to halve the rate of child obesity in Scotland is a strong ambition against which to measure progress, but achieving it will depend on what concrete steps we are prepared to take as a country to address obesity,” he said.
“Restrictions on marketing of unhealthy food and drink, better labelling, changes to planning policy, and the provision of free fruit and vegetables to primary school children are all important actions that doctors are looking to the Scottish Government to include in their coming obesity strategy.”
Meanwhile Caroline Cerny of Obesity Health Alliance said: “With over 29 per cent of children in Scotland at risk of being overweight or obese, it’s great to see Scottish Government making bold and much needed commitments to reduce childhood obesity.
“Restricting junk food marketing and promotions on unhealthy food is a key part of tackling the current environment which pushes us towards unhealthy choices.
“We’re pleased Scotland is leading the way on this - something that is strongly supported by the public and health experts.”