New research shows that fat people have generally become fatter in the last decade but thin people have generally stayed the same size.
Experts from Cancer Research UK studied the weight and waist measurements of almost 12,000 men and women in 1993-4.
They then compared these statistics with weight and waist measurements for a similar group of people taken from the Health Survey for England 10 years later.
The study, which has been published online in the International Journal of Obesity, aimed to examine the influence of environment on weight.
The researchers found that men's waist circumference increased by 3.48cm and women's by 4.35cm.
They also discovered that the proportion of men and women under 45 who were morbidly obese doubled over the 10 year period - as did the proportion of women with a Body Mass Index of more than 40.
Professor Jane Wardle, director of Cancer Research UK's health behaviour unit and study leader, said: "We found that weight gain in the population has been unequally distributed.
"Slimmer adults today are almost as slim as their counterparts 10 years ago but the heaviest people in the population are much heavier than they were 10 years ago.
"These inequalities are greatest among those under 45, suggesting that environmental changes are having a greater impact on young adults.
"It seems that some people are more susceptible to changes in the environment than others and the explanation for this may be partly genetic.
"It is important for psychologists, geneticists and biologists to work together to discover the reasons for this."
Cancer Research UK
Copyright © PA Business 2007
You are currently leaving the Nursing in Practice site. Are you sure you want to proceed?