Tensions simmered over in the obesity debate at this week's Westminster Diet & Health Forum. Liz Hamson reports

The National Consumer Council launched a stinging attack on the Food and Drink Federation at the Westminster Diet & Health Forum this week, claiming that manufacturers were not doing enough to tackle obesity.

Sue Dibb, the council's senior policy officer accused the FDF of "sticking two fingers up at the FSA by proposing a watered down version of traffic light labelling". Her outburst elicited a terse response from FDF director general Melanie Leech. "I don't think it's helpful to trade insults," she said. "We need to be more grown up about it."

The row exposed the deep rifts between industry, interest groups and government over traffic light labelling and advertising to children, and concluded a day of heated debate on combating obesity.

Things started sedately enough with a succession of experts reeling off stark statistics about the "public health time bomb" of obesity, in the wake of the Health and Social Care Information Centre's recent report claiming childhood obesity had doubled in the last decade and one third of children were now overweight or obese.

However, the mood began to turn as Dr Peter Marsh, director at the Social Issues Research Centre, questioned the robustness of the data and criticised the emotive language deployed. "People are predicting that 50% of children will soon be obese, that they will die before their parents or will go blind and lose limbs. Let's look at the facts."

His main bone of contention was the standards by which childhood obesity is defined: the UK standard used by the Health Survey for England, on which the report was based, or the international standard, which produces lower figures. "The international standard has been designed by the International Obesity Taskforce," he pointed out. "These figures are considered to be the ones we should be using and if we do, the prevalence drops to less than two and half times the figures we saw at the weekend."

He added that the UK measure for children was out of sync with that for adults: "According to the latest health survey, around 20% of male children are obese, but for 16 to 24s it miraculously drops to about 8%. So what happens between 15 and 16? Does all the fat fall off?"

The international standard would produce a far more realistic figure of around 7%, he said, adding: "Obesity is a problem of middle age. We're in danger of medicalising and demonising what used to be called middle-age spread.

Why are we publishing figures that exaggerate the problem? And what are the consequences of getting our response wrong because we imagine the scale of the problem to be two and a half times what it is?"

Dr Susan Jebb, head of nutrition and health research, MRC Human Nutrition Research, agreed that the international standard was better, but argued it was wrong to focus on the merits of various absolute values; it was the rate of increase that was important. The priority was to find ways to change behaviour, she said, praising the FSA's nutrient profiling and signposting work.

Picking up on the latter, Leech was keen to stress the "large level of agreement with the FSA on front of pack information".

Yet she reiterated the FDF's commitment to a Guideline Daily Amounts-based system.

"We believe that the GDA approach supported by an educational programme plays directly to our shared agenda and that the FSA and Department of Health's alternative traffic light system takes the dumbed down route. Neither view is based on a philosophical wish to go to war."

The FDF was "prepared to engage" with the FSA on monitoring the two systems in a "truly collaborative approach", she added.

Leech was equally forthright in her criticism of one of the four Ofcom proposals to restrict advertising to children. She dismissed the proposal that advocates restrictions on ads for brands that are high in fat, sugar and salt - so-called HFSS products - as "subjective and scientifically flawed" and a potential embarrassment to the government as it was based on the nutrient profiling model.

Dibb was having none of it. There were "a lot of dinosaurs, often under the guise of the FDF", she said, adding: "Melanie Leech has made clear her opposition to nutrient profiling and that is really not helpful. Guys, face up to the facts: the truth that you find so unpalatable is that we are eating less sugary drinks and Big Macs. It's time to go with the flow."

Unlike Dibb, most speakers and audience members agreed that the food and drink industry was not chiefly to blame for the nation's obesity and that it was genuinely attempting to tackle the problem. Leech was not the only person to mention the Small Change, Big Difference public health campaign, launched that morning.

The consensus was that with its emphasis on physical exercise and, more importantly, education, this was the sort of initiative that epitomised the multi-faceted approach needed.