Obesity and being overweight was now a major health problem here and "a symptom of our society". Studies due to be released next year are expected to show that Ireland's rates of overweight people and incidence of diabetes are near US levels, the Academy of Medical Laboratory Science 30th anniversary conference heard in Killarney.
Eating too much bread, larger portions, fast-food, as well as Indian and Chinese take-away meals, eating out, "grazing" and the demise of three good meals a day were contributing factors. So-called low-fat foods were often packed with sugars.
Over-eating in the sense of taking in more energy than was needed was the single biggest cause of being overweight, not genetic pre-disposition, or other popular beliefs, said Prof Barbara Livingstone of the University of Ulster at Coleraine.
If people wanted to lose weight, they had to expend more energy than they took in. "People have to become highly restrained eaters," she said.
However, too much restraint had extreme problems, she warned. Eating was one of the great pleasures in life and she cautioned against labelling foods good or bad.
Fewer people were eating three good meals a day, lack of exercise among children , sugary snacks and bigger portions had contributed to the "epidemic".
As many as 40 diseases from arthritis to diabetes, to respiratory problems, high blood pressure and cancer of the womb were linked with being over-weight and obese.
It was a greater contributor to heart disease than smoking, and being obese at 40 knocked seven years off a person's life-expectancy.
There were also psychological factors, including lower self-esteem and clinical depression.
Currently it is known that two out of three men are overweight or obese, as are half of women here. The highest rates of increase in obesity are in young men, she said.
A study on childhood obesity to be released next year will show a huge incidence of diabetes, the conference heard.
Type 2 diabetes normally found in 40-year-olds and controlled by diet and exercise was now seen in 12-year-olds, Dr Mary Ryan, consultant Endocrinologist, Barringtons Hospital, Limerick and a member of the National Task Force on Obesity said. The task force report due early next year will call for reduced food advertising to children.
Children were "hugely vulnerable" and were being aggressively targeted by the food industry. The advertising curb was likely to be controversial, but it was central to tackling the obesity problem among children, she said.
Dr Ryan singled out bread among women and breakfast rolls popular among men for criticism. She had found people skipped breakfast and over-compensated later with pastries.
She sometimes recommended an Atkins diet "in moderation" - protein which was highly filling combined with a little carbohydrate, although long-term it was not a good idea.
Ms Janis Morrissey, dietitian with the Irish Heart Foundation, called for a multi-agency approach. Tackling the weight crisis should not be left to the Department of Health alone, she said.
Labelling was sometimes misleading and needed to be clearer.