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Stress over the long term could make you fat

Sean Rossman
USA TODAY
A woman on a scale.

Calm down, that stress could cause you to pack on weight.

Researchers found long-term exposure to the stress hormone cortisol is tied to increased levels of obesity and wider waists.

It's been speculated that stress has been associated with weight gain, but the research, published Thursday in the journal Obesity, provides a link between long-term stress and obesity. The study notes, however, that it hasn't been determined whether high cortisol levels are a cause or symptom of obesity.

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The scientists, out of the University College of London, collected years of hair samples of about 2,500 people living in England. Hair, the study says, is used to indicate stress over the course of two months. Other tests could produce varying results depending on the time of day.

The study found obese participants had significantly higher levels of cortisol — the stress hormone — than people who were normal weight or overweight. The stress levels didn't differ much between those who were normal weight and underweight.

Cortisol levels also were higher in people with wider waists.

The study's authors says the results may help in future obesity research.

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