Obesity can cut life expectancy by up to eight years and cost people up to 19 years of healthy living.

A new study in the Lancet Journal has found that those with a Body Mass Index (BMI) of over 35 are likely to lose between one and eight years of life - while those with BMIs of 25 to 30 could lose up to three years.

The research shows the effects of obesity on life expectancy are far greater for young people and drop as age increases.

It says that the "effect on the number of healthy years lost is far greater than its effect on total years of life."

Professor Donal O'Shea is director of the weight management clinic at Loughlinstown Hospital.

He told Newstalk Breakfast he is not surprised by the findings.