Co-author Salim Merali said for the purpose of the study, six healthy males were “forced” to consume 6000 calories every day for a whole week — a diet consisting of about 50 percent carbohydrates, 35 percent fats, and 15 percent protein.
“It was a regular, American diet, composed of pizzas, hamburgers and that sort of thing,” he told New Scientist.
“They took to the diet, and liked it.”
The only catch was subjects were required to forgo any physical exercise for the entire duration of the experiment and were also forced to remain bed-bound so they could be carefully monitored.
“In that time, the men gained an average of 7.7 pounds and showed signs of insulin resistance as well as oxidative stress,” wrote the researchers.
This meant their sugar-absorbing insulin stopped working, which caused glucose to build up in their bloodstream instead of getting absorbed by their cells — a factor that can lead to diabetes.
Co-author Guenther Boden said while he expected to see some changes in the patients, he was shocked at just how fast they occurred.
“I was more surprised at the rapidity of the onset than the magnitude,” he told Yahoo.
“The change happened after a day or two — and became significant after three days.”
Boden said as researchers now had proof overeating can be instrumental in the development of type 2 diabetes, the challenge was to move the research forward.
“The very first thing we’re going to do is to see how reversible this is,” he said.
“Now that we know you can cause insulin resistance very quickly if you overeat, but what if you return to your normal eating habits with a lower caloric intake — how long will it take to go away?
And does it go away at all?