It turns out that your love of French fries and Big Macs might not be your fault. Until now, traditional thinking credited the senses of sight and smell with the consumption of fatty foods. A new study conducted by the Washington University School of Medicine found that, depending on the individual, certain human receptors are more sensitive to fatty foods.
Out of 21 obese subjects, ages 21 to 50, researchers discovered that those with a certain variation of the CD36 gene had a greater desire to eat more fat-laden foods.
The study, published in the Journal of Lipid Research, aimed to discover "What happens if we look for humans who have a lot or a little of the gene?" said first author M. Yanina Pepino, research assistant professor of medicine.
"We wanted to understand whether people can perceive fat through taste. Since animals can detect fat as a taste, we wanted to know if we could do it as well," Pepino said. "Fat is a critical element for life, although we demonize fat, we can't forget it is an evolutionary element that we need."
The study excluded participants with altered taste perception such as cigarette smokers or those who were pregnant.
Each participant was give three cups: two cups had water and the other cup had water and a small amount of fat. The participants had to taste the three cups to determine which one was different.
"A small amount of pure fat, oleic acid, the principle component of olive oil, was in one of the cups," Pepino said.
The researchers controlled the study so it was not based on smell, texture, or visual cues. To keep the study focused on taste, the participants had nose clips to avoid smell. The researchers also used Arabic gum to mask viscosity and white food dye to mask the color. A red light was also used to hide the color.
The study determined that "People with a high sensitivity level of this protein (CD36) require much less fat, while people with less sensitivity require much more fat," Pepino said.
Whether this study offers an answer to the obesity problem is still an open question, though, experts say.
"We cannot say that there is a cause and an effect," Pepino said. "There are many factors in the development of obesity. We'd like to learn does it [CD36] affect how much fat is absorbed? What are the consequences of this?"
"It may mean that the idea of obesity is more and more explainable, but in terms of treatment, I'm always going to think it comes down to lifestyle changes and a lifestyle decision," said Keith Ayoob, associate professor at the Albert Einstein College of Medicine in New York City.
Ayoob notes that obesity hasn't always been a problem in America and the human body hasn't changed much over time.
"What happened in the last 30 years?" he said. "We stopped moving. Technology has allowed us to have so many more leisure activities that we can do without moving."