HEALTH RESEARCH:DESPITE PROVIDING great health benefits exercise is not the best way to tackle obesity. Drastic reductions in calorie intake are the most effective way to counter this growing health problem, a researcher has claimed.
Prof John Speakman of the University of Aberdeen presented challenging findings at the UK Festival of Science in Birmingham yesterday. They showed our activity levels had not changed over the last 30 years and that the “obesity epidemic” was mainly caused by increases in the amount we eat.
Tackling the problem using exercise was impractical, he said. “Exercise is a good idea but if you want to reverse the obesity epidemic that is not the solution.”
He presented data from studies in Europe and North America from the 1980s to the present day. It was widely assumed that we have become less active over the last few decades and that this was a major cause of the obesity epidemic, but this was not the case.
Together the studies showed that there was no significant change in activity level over the last 30 years, which implies that inactivity was not the cause of the problem. Although our lifestyles had changed, including increases in car ownership and time spent watching television, Prof Speakman argued that while the type of activities had changed, our overall activity level – our energy expenditure – had not decreased.
“TV viewing has expanded in a time slot when we’ve always been inactive,” he said. Television had simply replaced equally sedentary activities such as listening to radio or reading.
The body naturally compensates for changes in activity to maintain a consistent energy expenditure, he said. On a very active holiday we might “go from sitting at a desk to biking eight hours a day” but then “sleep goes from seven hours to 12 hours per day” to compensate, he suggested. If lack of exercise was not to blame then the obesity epidemic must be caused by an increase in the amount that we eat.
We were definitely buying more food than in the past, as shown in consumer statistics. And while it was possible that people were throwing more away, sales of chocolate in the UK doubled from 1997 to 2005 and this was a food very rarely thrown away.