Several studies have suggested health benefits of whole grains and high dietary fiber intake, including for glycemic control and insulin sensitivity.
There has been controversy, however, about whether whole grains and fiber are beneficial for weight regulation, partially because there hasn’t been data from controlled metabolic studies.
The new study, led by Dr. Phil Karl of the U.S. Army Research Institute of Environmental Medicine and Tufts University, provided food to participants for eight weeks and may help explain how whole grain consumption is beneficial for weight management.
People who ate a diet with whole grains lost close to an extra 100 calories per day due to a combination of increased resting metabolic rate and greater fecal losses. This is compared to people who ate refined grains without much fiber.
Based on previous research and current study measurements, however, they believe that the calorie loss was not due exclusively to the digestion of extra fiber intake.
The 2015-2020 Dietary Guidelines for Americans from the United States Department of Health and Human Services and the USDA recommends that Americans replace refined grains with whole grains.
The recommended daily allowance of whole grains is a minimum of 3 ounces of whole grains for women and 4 ounces for men. This is the equivalent to consuming 1.5-2 cups of brown rice or oatmeal each day.