People who only focused on eating 30 grams of fiber per day lost almost as much weight as those who followed a more complicated diet, according to a new year-long study.
A "permissive" dietary plan, like focusing on increasing fiber, may produce more beneficial effects than a "restrictive" plan, like reducing saturated fat, said lead author Dr. Yunsheng Ma of the University of Massachusetts Medical School in Worcester.
"We chose dietary fiber because it exerts clinical benefits on several components of metabolic syndrome, including waist circumference, glucose and lipid homeostasis and insulin control, in addition to body weight and regulation of certain inflammatory markers," Ma wrote in an email to Reuters Health.
For the new study, Ma and his coauthors divided 240 obese adults with metabolic syndrome into two groups. One group followed the American Heart Association (AHA) diet plan and the other aimed to eat at least 30 grams of fiber per day.
About 25 percent of adults worldwide have metabolic syndrome, which includes symptoms like a large waistline, high blood pressure, high blood sugar, low levels of HDL (good) cholesterol and high levels of triglycerides, which increase the risk of cardiovascular disease and diabetes.
The American Heart Association Eating Plan recommends that adults consume 25 to 30 grams of fiber daily from foods, such as vegetables, legumes or whole grains, although the average American only eats about 15 grams per day.
The AHA diet calls for increasing intake of fruits and vegetables, whole grain or high fiber foods and lean proteins, minimizing sugar, sodium, alcohol, saturated fats, trans fats and cholesterol, and eating fish twice weekly. People on the AHA diet were given individualized calorie and saturated fat goals.
After one year, people in both groups had lost weight and improved their blood pressure, dietary quality, and insulin resistance, according to results in the Annals of Internal Medicine.
But the high-fiber group had lost an average of about four and a half pounds, compared to nearly six pounds in the AHA diet group. Also, seven people in the fiber group developed diabetes over the yearlong study, compared to only one in the AHA group.
The high fiber diet still showed positive results and was easy to follow, which often leads to more successful diet compliance, according to Julia Zumpano, a registered dietitian at the Cleveland Clinic who works closely with the department of preventive cardiology.
High fiber intake is one of the most important aspects of the AHA diet, she wrote in an email to Reuters Health.
"Fiber fills you up, expands in your stomach, fiber also keeps you fuller longer," said Zumpano, was not part of the new study. But it may need to be limited for people with any kind of bowel issues or a history of diarrhea, she noted, and the other aspects of the AHA diet do have benefits as well.
Americans in general have a lot of room for improvement with fiber intake, Ma said. Legumes, barley and other whole grains, nuts, seeds, fruits and vegetables are all fiber sources.
"However, we ask not to rely on fiber supplements or any one food to increase daily fiber, but rather to obtain fiber from a variety of foods in their diet as suited to individual tastes and preferences," he said.
© 2015 Thomson Reuters. All rights reserved.