It is often assumed that those on low incomes and with low levels of education are overly represented in the major increase in obesity of recent decades. A new thesis from the Lund University School of Economics and Management, Sweden, shows that obesity is increasing across all social groups and that we need to look at factors other than socioeconomic status to understand and solve one of the major public health concerns of the Western world.

Åsa Ljungvall, a researcher in economics at the Lund University School of Economics and Management, has studied the increase in numbers of people who are overweight or obese over recent decades in Sweden and the US.

"My studies show that the increase in the problem of obesity is taking place across a broad front in all socioeconomic groups. So even if there are differences between different levels of education and income, people are affected fairly evenly by the increase -- sometimes even in ways that reduce inequality between the groups. The obesity epidemic is taking place independently of socioeconomic status and affects people more equally than we have previously thought," says Åsa Ljungvall.

Even if the average waist measurement of a Swede is less than that of an average American, Åsa Ljungvall's comparative studies indicate similarities.

"We are seeing the same tendency in Sweden as in the US, where the increases in obesity, severe obesity and BMI since 1960 are very similar for groups with different levels of education and income."

"As we are seeing major increases in all socioeconomic groups, it is perhaps not related to the fact that we don't know any better or cannot afford to do otherwise. There is something else that affects our behaviour more."

So why have we become larger and what can be done about the problem? In Åsa Ljungvall's view, we need to look at something other than socioeconomic factors like education and income to understand and solve one of the major public health problems of the Western world. It is important to keep the distribution of the problem in mind when discussing causes and possible solutions.

At the same time as the major rise in obesity, we have experienced rapid economic and technological development, which is likely to have influenced what choices we make with regard to diet and physical activity. These changes seem to have entailed difficulties in maintaining a healthy lifestyle and weight.

"How are we affected by factors such as quality and quantity of available food and drink, stress and uncertainty, opportunities for daily exercise, marketing and information?" asks Åsa Ljungvall rhetorically. "Factors such as these affect how difficult it is for people to make the 'right' choices and create good habits and norms."