One of the ideas that can drive me crazy is the idea that overweight people are just lazy about their health. Besides being rude, this is a gross oversimplification of the complicated factors of health and maintaining a healthy weight.

With that myth in mind, researchers at the University of California will soon publish their study results in Physiology and Behavior, showing a different pathway for how our eating habits affect our ability to do tasks and maintain good health. This was an animal trial using rats, as rats have similar physiological systems to humans.

In the six-month study, two groups of female rats were fed either an unprocessed diet, or a lower quality processed diet. The healthier diet contained foods such as ground corn and fish meal, while the unhealthy diet contained processed foods and more sugar, with the intent of mimicking a human junk food diet.

After three months, the rats eating the healthy diet were a healthy weight, while those eating a junk food diet had become obese.

Observation number one: A higher sugar, processed diet does appear to contribute to obesity. No surprise there.

The researchers set up a task for the rats where they would need to press a lever to receive a reward of food or water. They found that the obese rats fed the unhealthy diet took significantly longer breaks (almost twice as long) than the healthy diet group.

Observation number two: The obese rats had much less energy and endurance than the healthy weight rats. This would make the obese rats seem “lazy,” but really their lack of energy is connected to their poor diet, rather than a personal character fault. The lead researcher of this study concluded this study suggested that lethargy might be caused by a junk food diet.

He states, “"Overweight people often get stigmatized as lazy and lacking discipline. We interpret our results as suggesting that the idea commonly portrayed in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause, rather than an effect, of laziness"

After six months, the researchers switched the diets of the two groups for nine days. The lean rats didn’t gain weight, or lose energy during the lever challenge during that time, while the obese rats didn’t improve their weight or energy during those nine days.

Observation number three: Long-term dietary actions are key to lasting and real change.

And finally, at the end of the study, the obese rats were found to have more, and bigger, tumors in comparison to the lean rats.

Observation number four: This isn’t simply about weight, but about health. Eating a poor diet meant lethargic, overweight and sick rats.

And that’s something for us all to think about, whether we gain weight on junk food or not. 

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