Prof Susan Jebb, from the University of Oxford, said the study did not show if the traits explained people's weight.
Around 67% of men and 57% of women are either overweight or obeseaccording to their Body Mass Index.
"It is just a measure of height and weight and I think it generalises everyone into this one group and that's not the case really," said lead researcher Dr Mark Green at the University of Sheffield.
The team there used the Yorkshire Health Study to analyse the health and behavioural characteristics of obese people.