When food is eaten, the level of glucose in the blood rises. The body's muscle is a major clearinghouse for this glucose. It may break it down for energy, or it can store it for later use. Since muscle makes up about 30 percent of our body weight and it is such an important site for glucose metabolism, if normal metabolism is altered, it can have consequences on the rest of the body and can lead to health issues.
In the study, healthy college-age students were fed a fat-laden diet that included sausage biscuits, macaroni and cheese, and food loaded with butter to increase the percentage of their daily fat intake. A normal diet is made up of about 30 percent fat and students in this study had diets that were about 55 percent fat. Their overall caloric intake remained the same as it was prior to the high fat diet. Muscle samples were then collected to see how it metabolized glucose. Although the study showed the manner in which the muscle metabolized glucose was altered, the students did not gain weight or have any signs of insulin resistance.
The authors write in Obesity that muscles' ability to oxidize glucose after a meal is disrupted after five days of eating a high-fat diet, which could lead to the body's inability to respond to insulin, a risk factor for the development of diabetes and other diseases.
"Most people think they can indulge in high-fat foods for a few days and get away with it," said Matt Hulver, an associate professor of human nutrition at Virginia Tech. "But all it takes is five days for your body's muscle to start to protest. This shows that our bodies are can respond dramatically to changes in diet in a shorter time frame than we have previously thought. If you think about it, five days is a very short time. There are plenty of times when we all eat fatty foods for a few days, be it the holidays, vacations, or other celebrations. But this research shows that those high-fat diets can change a person's normal metabolism in a very short time frame."
The authors are now interested in examining how these short-term changes in the muscle can adversely affect the body in the long run and how quickly these deleterious changes in the muscle can be reversed once someone returns to a low-fat diet.