New research from the U.K. reveals that changes in lifestyle over the past 30 years have led to a sharp reduction in the strenuousness of daily life — a finding investigators believe may explain the dramatic rise in obesity.
Researchers from Royal Holloway, University of London discovered that while obesity rates have almost trebled, our actual calorie intake has fallen by around 20 percent compared to 30 years ago.
Study leaders Dr. Melanie Luhrmann, Professor Rachel Griffith, and Dr. Rodrigo Lluberas believe that as our lives have become more sedentary, we gain weight even as we eat less.
Investigators found that both men and women are more likely to work in less strenuous occupations than in the past. Work is important because it accounts for a large share of people’s time but the academics also noted that how people spend time outside of work has also changed.
For example, both men and women spend more time watching TV and more time commuting by public transport or car which are much less strenuous than walking or cycling.
The research also found a link between work and calories with many workers eating out more and purchasing less calories for home consumption.
This suggests that the success of policy interventions aiming to reverse the rise in obesity by changing people’s food purchasing behavior may depend on taking interactions between work and calories into account.
Researchers believe their findings show that decisions over work and food demand are related. In one area, they found that working individuals may substitute processed foods and eating out rather than market-produced food.
Secondly, weight gain arises from a caloric imbalance, meaning people gain weight if more calories are consumed than expended. Therefore, both calories and physical activity are important in explaining the rise in obesity.
“People have adjusted their calories downwards, but not enough to make up for the sizable decline in physical activity. Part of this decline comes from reduced activity at work. So we should take into account the link between work and calories when evaluating policy interventions aimed at reducing obesity,” said Luhrmann.