Switching from a diet of refined to whole grains may help to achieve weight loss goals and bolster health, according to a new study published Wednesday.
The findings, released in the American Journal of Clinical Nutrition, suggest that eating whole grains is connected with an increase in calorie loss because it boosts metabolism and reduces the amount of calories that are retained during digestion.
"This study helps to quantify how whole grains and fiber work to benefit weight management, and lend credibility to previously reported associations between increased whole grains and fiber consumption, lower body weight and better health," said Phil J. Karl, the lead author of the study and a nutrition scientist at the U.S. Army Research Institute of Environmental Medicine, in a statement.
Whole grain foods -- which include wheat, rice, oat and barley products -- are the type of food that includes the outermost, nutrient-rich layer of grains. Often, this fiber heavy layer is removed during the refining process.
"There’s basically three components [in whole grain foods]," Dr. Jennifer Ashton, ABC News' chief women's health correspondent, said today on "Good Morning America." "There’s the bran, the germ and then something called the endosperm, that’s where you have the fiber, the antioxidants, the vitamins."
"[In] refined grains, most of that is stripped away," said Ashton, who was not involved in the study. "Basically, that’s the difference, you’re getting fiber and nutrients in whole grains."
For the study, researchers recorded the weight, metabolic rate, blood glucose, fecal calories, hunger and fullness for 81 participants over an eight week period. After an initial period of two weeks where all participants were given the same foods, the researchers fed some of the participants a diet with whole grains and some a diet with refined grains. The study was conducted at the Energy Metabolism Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging (HNRCA)at Tufts University.
According to a statement released by Tufts University announcing the study, the scientists found that those who ate whole grain foods burned an extra 100 calories per day because of their increased resting metabolic rate and greater fecal losses when compared to the group that ate mostly refined grains. The extra calories lost by the whole grain eaters equaled the calories burned in a brisk walk or a small cookie, according to the study's author.
The study had one caveat: it did not compare the grain eaters to a group that avoided grains completely, according to Ashton.
"But head-to-head, refined versus whole, the whole grains did better," she said.
Ashton recommends paying close attention to labels when incorporating whole grains into your diet. She also recommends choosing brown foods and looking for foods high in fiber.
"Sometimes whole grains can be deceiving but you’ll never do wrong if you look at the labels first," she said.