The food industry has come under attack during an investigation into childhood obesity by BBC Wales.
Tina Bailey blames her daughter Cerys' obesity on advertising
The industry is accused by some parents of deliberately manipulating children into eating high sugar or high fat products.
But a manufacturers' trade group told BBC Wales' current affairs programme Week In Week Out that they offer choice and that children represent a legitimate market.
Obesity is a growing problem for the NHS, costing taxpayers billions of pounds.
Adult obesity rates have tripled since 1982 with 19% of Britons now counted as obese and 39% overweight.
She doesn't see the cheese, she sees the little thing bouncing around and she wants to eat it
But childhood obesity is also increasing rapidly with the number of obese children doubling since 1982.
Around 10% of six-year-olds are obese, rising to 17% of 15-year-olds.
Obesity can lead to health problems, including arthritis, heart disease and diabetes.
Parent Tina Bailey, of Barry, south Wales, told Week In, Week Out that advertising aimed at children had led to her three-year-old daughter, Cerys, demanding the products she saw on television.
Cerys weighs the same as an average 10-year-old.
There is a shortage of treatment for overweight people
According to her mother, her weight is causing health problems and preventing her from making friends with other children.
Ms Bailey said: "Cerys sees the cheese strings bouncing around on the TV.
"She doesn't see the cheese, she sees the little thing bouncing around and she wants to eat it."
But manufacturers have defended their decision to aim some advertisements at children, saying they offer choice.
Martin Patterson, of the Food and Drink Federation, said: "Children have got money to spend, they are consumers.
"It would be absolutely wrong, surely, to just cut them off entirely."
Week In Week Out also discovered that while the number of people with obesity in Wales is rising, there is a chronic shortage of community dieticians.
Cardiff and the Vale of Glamorgan has just one paediatric dietician, who has a waiting list of 15 months.
Obesity surgeons are equally scarce, with just 13 working across the UK.
Professor John Baxter , Professor of Surgery at the University of Wales, Swansea, said around 100 specialist surgeons are needed to tackle the problem.
In Wales, he estimates 5,000 people need surgery to reduce their size.
Professor Baxter is only able to perform 20 operations a year and his current waiting list is three years.
"If you're morbidly obese, and you haven't started to suffer yet, you have only a one in seven chance of reaching the normal life expectancy because people die prematurely of strokes and heart attacks" says Professor Baxter.
Welsh assembly Health Minister Jane Hutt acknowledged there were serious health problems linked with obesity in Wales.
She said: "Obviously I am extremely concerned and I hear situations, not just in terms of people being overweight but the impact of it in terms of heart disease.
"We know there are huge problems and of course I'm concerned and I want to take this forward."
Week in Week Out is on BBC One Wales at 2235 BST, Tuesday, 17 June and on digital channel 2W at 2115 BST on Wednesday, 18 June.