"A high-fiber diet can be filling and tasty, making it a pleasure to eat while losing weight and improving health and well-being," says study co-author Barbara Olendzki.
Researchers at the University of Massachusetts (UMass) in Amherst wanted to test a theory that increasing fiber would be an easier to follow and more effective diet than the complex American Heart Association (AHA) diet.
Unlike the AHA diet, which restricts dieters from consuming certain foods, the high-fiber diet simply encourages people to eat more fiber-filled foods. The researchers believed that as this approach is more permissive, people might find it easier to stick with than restrictive dieting.
"A high-fiber diet can be filling and tasty, making it a pleasure to eat while losing weight and improving health and well-being," says Barbara Olendzki, RD, MPH, assistant professor of medicine and co-investigator on the study.
The team enrolled 240 adult participants who were considered to be at risk of developing type 2 diabetes. Half of the participants were randomized to follow the high-fiber diet and half followed the AHA diet.
Followers of the high-fiber diet were told to increase their fiber intake by at least 30 g a day. The AHA diet was more complex with 13 components, including:
- Limiting calories by eating more fruits, vegetables and whole grain foods
- Consuming at least 30 g of fiber per day
- Choosing lean proteins
- Reducing sugar and salt consumption
- Drinking little or no alcohol
- Balancing fat, carbohydrate, protein and cholesterol consumption to specific ratios.
After 12 months, the participants on the AHA diet had lost 6 lbs on average, and the high-fiber participants had lost an average of 4.6 lbs. During the trial, all participants demonstrated lower blood pressure and improved insulin resistance and fasting insulin.
The researchers say that both diets were effective at providing clinically significant weight loss as well as offering protective benefits against diabetes and metabolic syndrome.
"We were encouraged to see the decline of fasting insulin in the high-fiber group at 12 months," says Dr. Yunsheng Ma, associate professor of medicine in the Division of Preventive and Behavioral Medicine at UMass. "Long-term improvements in insulin resistance have significant clinical implications for patients with metabolic syndrome."
AHA diet resulted in slightly more weight loss, but high-fiber diet is simpler to follow
Although participants following the AHA diet lost more weight on average, Dr. Ma believes the high-fiber diet has the advantage of being much simpler to follow:
"The more complex AHA diet resulted in slightly larger (but not statistically significant) weight loss, but a simplified approach emphasizing only increased fiber intake may be a reasonable alternative for individuals who find it difficult adhering to a more complicated diet."
"We found that increasing dietary fiber was accompanied by a host of other healthy dietary changes," adds Sherry Pagoto, PhD, associate professor of medicine and co-investigator on the study, "likely because high-fiber foods displaced unhealthy foods in the diet. Asking people to make one dietary change can have collateral effects on the rest of their diet. We hope to study this further."
In 2014, Medical News Today reported that a high-fiber diet may also protect against asthma.