One thing to add to your diet if you want to lose weight

A simple high-fiber diet can provide health benefits while being easier to stick with than a diet calling for multiple changes in eating habits, a new clinical trial concludes.

People who only added more fiber to their otherwise normal diet were able to lose weight, lower their blood pressure and reduce blood sugar levels -- all key to staving off diabetes and improving overall health.

They didn't lose quite as much weight as people following a more complex lifestyle diet recommended by the American Heart Association (AHA). But the study authors contend that their findings are encouraging for those daunted by complicated guidelines.

"For people who find it difficult to follow complex dietary recommendations, a simple-to-follow diet with just one message -- increase your fiber intake -- may be the way to go," said study author Dr. Yunsheng Ma, an associate professor in the division of preventive and behavioral medicine at the University of Massachusetts Medical School in Worcester.

The U.S. National Institutes of Health-funded study involved 240 adults who were at risk for developing type 2 diabetes. Researchers asked them to change their diets for one year.

Half were just asked to increase their fiber intake to at least 30 grams per day. They had to get their fiber from foods, not supplements, which meant eating more fruits, vegetables and whole grain foods. Otherwise, they could eat whatever they wanted.

"High-fiber foods are rich in vitamins and other essential nutrients, so they provide many benefits" over fiber supplements, Ma said.

The other half were asked to follow the AHA diet guidelines, which contain 13 components, researchers said. These include eating more fruits and vegetables, reducing sugar and salt consumption, choosing lean proteins, cutting back on alcohol consumption, and carefully balancing intake of protein, fats and carbohydrates.

The researchers theorized that the high-fiber diet would be easier to follow, easier to stick with and, thus, more effective.

As it turned out, 12 of the 121 high-fiber dieters dropped out during the course of the study, compared with 15 of the 119 AHA dieters.

The average weight loss after a year was about 6 pounds for the AHA dieters and 4.6 pounds for the high-fiber followers, but all participants experienced lower blood pressure and reduced blood sugar levels.

Eight participants developed type 2 diabetes during the trial: seven in the high-fiber diet group and one in the AHA diet group.

The results show that "one small step can have a big impact in your battle with the bathroom scale," said Joan Salge Blake, a clinical associate professor at Boston University's Sargent College of Health and Rehabilitation Sciences. "If you want to focus on one thing you can do in 2015 to help you lose weight, it might be increasing your fiber from whole grains, fruits and vegetables."

People who increased their fiber intake found that high-fiber foods tended to "crowd out" unhealthier options, Ma said.

"In the high-fiber group, we only asked them to increase fiber," he said. "However, we found that increasing dietary fiber was accomplished by a host of other healthy dietary changes, likely because high-fiber foods displaced unhealthy foods -- such as fatty and sugary foods -- in the diet."

Salge Blake, who serves as a spokeswoman for the Academy of Nutrition and Dietetics, agreed.

"If you add more fruits and vegetables in your diet, they're full of fiber and water. They're going to fill you up before they fill you out," she said. "I'm getting the fiber in the fruits and the vegetables, and they're going to displace the cookies and cakes and candies."

There are drawbacks to a high-fiber diet. Some people may experience gas, digestive discomfort and changes in bowel habits, Ma said.

"When significant problems were identified, the patient was asked to stop the intervention immediately and the study dietitian notified the patient's health care provider for an evaluation during this study," he said. "Patients were asked to increase fiber intake slowly, as tolerated, to target levels. They were advised to increase fluids. However, we only noticed a few adverse events."

Although focusing only on fiber proved effective, Salge Blake said she remains a big supporter of the AHA dietary guidelines.

"Those guidelines cover multiple problems and conditions other than obesity," she said. "They are good guidelines."