Too many calories to blame for America’s obesity epidemic

May 11th, 2009 - 12:23 pm ICT by IANS  

Sydney, May 11 (IANS) Are too many calories to blame for the raging obesity epidemic in the US? The answer is yes, according to an exhaustive study that squarely blames excessive energy intake for bulging waistlines since the 1970s.
“This study demonstrates that the weight gain in the American population seems to be virtually all explained by eating more calories,” said Boyd Swinburn, head of population health at Deakin University who led the study.

The scientists started by testing 1,399 adults and 963 children to determine how many calories their bodies burn in total, under free-living conditions. The test is the most accurate measure of total calorie burning in real-life situations.

Once they had determined each person’s calorie burning rate, Swinburn and his colleagues were able to calculate how much adults needed to eat in order to maintain a stable weight and how much children needed to eat in order to maintain a normal growth curve.

They then worked out how much Americans were actually eating, using national food supply data (the amount of food produced and imported, minus the amount exported, thrown away and used for animals or other non-human uses) from the 1970s and the early 2000s.

The researchers used their findings to predict how much weight they would expect Americans to have gained over the 30-year period studied if food intake were the only influence.

“If the actual weight increase was the same as what we predicted, that meant that food intake was virtually entirely responsible. If it wasn’t, that meant changes in physical activity also played a role,” Swinburn said.

The researchers found that in children, the predicted and actual weight increase matched exactly, indicating that the increases in energy intake alone over the 30 years studied could explain the weight increase, said a Deakin release.

“For adults, we predicted that they would be 10.8 kg heavier, but in fact they were 8.6 kg heavier. That suggests that excess food intake still explains the weight gain, but that there may have been increases in physical activity over the 30 years that have blunted what would otherwise have been a higher weight gain,” Swinburn said.

These findings were presented May 8 at the European Congress on Obesity.

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