Yunsheng Ma, MD, PhD, associate professor of medicine and lead author on the study
A new study by UMass Medical School researchers finds that in terms of dieting, keeping it simple may be all that is necessary. Results of the study were published in the Annals of Internal Medicine on Feb. 16.
Yunsheng Ma, MD, PhD, and colleagues compared the weight loss and dietary quality of participants on the American Heart Association diet to those on a simple high fiber diet. They found that although weight loss was slightly higher for the AHA diet, both produced clinically significant weight loss, lowered blood pressure and improved insulin resistance—all key to staving off diabetes and improving overall health.
“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,” said Dr. Ma, associate professor of medicine in the Division of Preventive and Behavioral Medicine.
The NIH funded study, A Simple Dietary Message to Improve Dietary Quality for Metabolic Syndrome, enrolled 240 adult participants who were at risk for developing type 2 diabetes. Half were randomized to the high fiber diet and half assigned to the multicomponent AHA diet. The instructions for the high fiber diet called for simply increasing fiber intake to at least 30 grams per day. The AHA diet guidelines have 13 components, including limiting calories by eating more fruits, vegetables and whole grain foods; consuming at least 30 grams of fiber per day; choosing lean proteins; reducing sugar and salt consumption; drinking little or no alcohol; and balancing fat, carbohydrate, protein and cholesterol consumption to specific ratios.
The researchers theorized that the easier to follow, permissive (eat more of this) diet of increasing fiber from a variety of food sources would result in greater effect than the restrictive and complex diet, because it would be easier to follow and thus easier to stick with.
“A high fiber diet can be filling and tasty, making it a pleasure to eat while losing weight and improving health and wellbeing,” said Barbara Olendzki, RD, MPH, assistant professor of medicine and co-investigator on the study.
The average weight loss after 12 months was 6 lbs. for the AHA followers and 4.6 lbs. for the high-fiber followers; all participants experienced lower blood pressure and showed improvement in insulin resistance and fasting insulin during the trial, which indicate this may be effective at warding off diabetes. These results suggest that focusing on a targeted fiber goal as a dietary intervention can be as clinically effective as the more intense AHA diet guidelines.
In addition to clinically significant weight loss, participants experienced improvements in metabolic syndrome, including lower blood pressure and decreased insulin resistance.
“We were encouraged to see the decline of fasting insulin in the high fiber group at 12 months. Long-term improvements in insulin resistance have significant clinical implications for patients with metabolic syndrome,” said Ma.
Sherry Pagoto, PhD, associate professor of medicine and co-investigator on the study, added, “We found that increasing dietary fiber was accompanied by a host of other healthy dietary changes, 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.”