Whole Grains May Help Weight Loss

Whole grains have been shown to be superior in the diet when compared with refined grains, suggests new research published in the American Journal of Clinical Nutrition. Whole grains increased calorie loss by decreasing the number of calories retained during digestion, while simultaneously speeding up metabolism. 

Previous research has indicated that whole grains and high dietary fiber intake have several health benefits, such as for glycemic control and insulin sensitivity. However, scientists have been unable to agree whether whole grains and fiber help to regulate weight.

The grain food group includes rice, oats, wheat, and barley. While whole grains contain the whole-grain kernel and include brown rice, oatmeal, and whole-wheat flour, refined grains are starches that are processed and milled to remove the bran and germ to prolong their shelf life. Examples of refined grains include white rice, white bread, and white flour.

Milling empties the starch of dietary fiber, iron, and B vitamins. Although iron and B vitamins can be added back into the refined grains, the fiber is not often reintroduced.

In the new research, investigators conducted a study over 8 weeks that included 81 men and women aged between 40 and 65. All food was provided to the participants over the course of the study and included either whole grains or refined grains. Participants were asked only to consume the food provided and continue with their usual levels of physical activity, medicalnewstoday.com reported.

“We provided all food to ensure that the composition of the diets differed only in grain source,” says senior author Susan B. Roberts, Ph.D., senior scientist and director of the Energy Metabolism Laboratory at the USDA Human Nutrition Research Center on Aging.

Participants who consumed whole grains - an amount that matched the recommended daily allowance for fiber - lost almost an extra 100 calories per day than the participants who consumed refined grains without much fiber.

“The extra calories lost by those who ate whole grains was equivalent of a brisk 30-minute walk - or enjoying an extra small cookie every day in terms of its impact,” says Roberts.

“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, Ph.D., first author of the study, an alumnus of the Friedman School of Nutrition Science and Policy at Tufts, and a nutrition scientist.