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Obesity: lack of exercise or too much food?

What can we blame the obesity crisis on? Is it a change in eating habits or physical activity. Researchers took an innovative approach to try to answer that question.

There has always been an assumption that both reduced physical activity and increased energy intake have created the obesity boom. I was surprised by what they found!

The rise in obesity in the United States since the 1970s was mostly due to increased energy intake, according to this new study.

The obesity cause study

This study was done a little differently so bare with me as I try to explain. :)

Firstly, scientists tested 1,399 adults and 963 children to find out how many calories their bodies burn. The test used is the most accurate to determine total calories burnt in real life situations.

Once they knew each person’s calorie burning rate, researchers could work out how much the adults needed to eat in order to maintain a stable weight. They also worked out how much children needed to eat to maintain normal growth.

Scientists then determined how much Americans were eating, using national food supply data from the 1970s and 2000s. They could predict how much weight they would expect Americans to have gained over the 30 years if food intake were the only influence. This was compared to data from a national survey (NHANES) which records the actual weight gain of Americans from the 1970s to the 2000s.

What did they find?

In children, the predicted and actual weight increase matched exactly! This shows that the increases in calories and food intake alone over the 30 years explains the weight increase in children.

In adults, scientists predicted they would be 10.8 kg heavier. They were actually 8.6 kg heavier. It shows that an increase in food is still responsible for weight gain, but that an increase in physical activity has reduced the gain slightly.

Lets go back to the slimmer 70’s!

The researchers suggested to reverse habits to return to the 70’s when Americans were slimmer they would need to:

  • cut out 350 calories a day for children. Eg: 1 can of soft drink and small French fries.
  • cut out 500 calories a day for adults. Eg: 1 large hamburger.

Researchers stressed that physical activity is a contributor to reducing obesity and offers greater health benefits that just helping to reduce weight. However, the study shows that people need to eat less and that ‘you are what you eat!’

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About Kellie

Kellie is 37 years old and together with her brother Steve makes up the My Health Software team.

She helps on the websites and gathering news for the programs. Kellie worked in the medical industry prior to having her two children (8 and 6) and has a strong interest in self awareness and management of health conditions.


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