Do not be surprised if there are people who barely gain weight when eating the same portion as those who are overweight, they might have a hormone called orexin. A new study shows that orexin-deficient mice gained more weight when fed with high-fat diet compared to mice that wasn’t deficient in orexin.
Orexin is a small protein (peptide) released in the brain. The hormone helps control weight gain because it’s involved in the body’s production of brown fat, which burns calories rather than storing them as fat.
Although the new findings are preliminary, researchers suggest that supplementing this hormone may be one way to help people lose weight.
The researchers compared normal mice with mice engineered to be deficient in orexin. When fed a high-fat diet for six weeks, the orexin-deficient mice increased their body weight by 45 percent, while the normal mice increased by just 15 percent.
The research result showed that an increased weight gain in orexin-deficient mice happened even though the mice ate less than normal mice.
“Without orexin, mice are permanently programmed to be obese. While with orexin, brown fat is activated and so they burn more calories,” said researcher Devanjan Sikder, an assistant professor at the Sanford-Burnham Research Institute.
“Our study provides a possible reason why some people are overweight or obese despite the fact that they don’t over eat,” Sikder said in a report published in the journal Cell Metabolism.
In humans, the orexin deficiency is often found in people with narcolepsia, a chronic sleep disorder, characterized by an excessive drowsiness during the daytime. In other words, people with daytime sleepiness are more likely to be obese despite eating less food.