Transcript: Obesity-Causing Chicken Virus
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
You may have seen headlines like this, suggesting that infection with certain viruses can contribute to obesity. According to a new review published this year: Viral obesity: fact or fiction?
It all started about 20 years ago. A never-before-described poultry virus emerged, killing thousands of chickens. That’s par for the course. But the strange thing about the new virus is that the survivors became fat. Normally, when you survive a serious viral infection, you lose weight, but infection with this virus made them gain 50% more abdominal fat than uninfected birds. This was the first virus ever discovered that could cause obesity.
And the virus was spread through feces, so you put one fat, infected chicken in a room, and all the chickens become fat and infected. The kicker is that it didn’t happen by boosting their appetite or something; they ate the same amount of food, but the virus just made them start piling on tummy fat, anyway.
So, researchers immediately started taking blood samples from overweight people to see if they were infected with the chicken virus. They found that not only do one in five obese humans test positive for exposure to this virus, those exposed to the virus weighed 33 pounds heavier than those who weren’t exposed. This is in kilograms; those positive for the virus averaged about 210 pounds; those testing negative for the virus were only 177 pounds; 33 pounds different.
Infectobesity: obesity of infectious origin. So where does this leave us? The recognized risk factors of obesity include overindulgence, lack of exercise, lifestyle, food habits, environment, stress, heredity, and genetic factors. All these factors are components of a multifactorial model of obesity.
The current evidence adds to our knowledge that viral infection could probably be considered another component cause—although not a necessary cause—of obesity in humans. Meaning, you can be fat on your own, with no help needed from some chicken virus, but it may be a contributing factor.
May be one reason why, for many people, the pounds just don’t seem to come off. Maybe that’s one of the reasons why, in a study of 40,000 men and women last year, one of the foods most closely tied to expanding waistlines was poultry.
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