PHILADELPHIA—A low-fat vegan diet made available on the job decreases body weight and cardiovascular risks in adults who are overweight and/or have type 2 diabetes compared with the standard American diet, investigators reported at the 72nd Scientific Sessions of the American Diabetes Association.

Suruchi Mishra, PhD, Clinical Research Coordinator at Washington Center for Clinical Research, a subsidiary of the Physicians Committee for Responsible Medicine in Washington D.C., and colleagues randomized individuals at 10 worksites to a vegan or control group.

The vegan group was asked to follow a diet consisting of whole grains, vegetables, legumes, and fruits, and also to avoid animal products and minimize added oils. They also were encouraged to select foods with a low glycemic index. In addition, they were advised to take a daily B12 supplement. Controls were given no dietary advice.

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Study participants were recruited from a major U.S. insurance company.

Results from 212 individuals who completed anthropometric and laboratory assessments at the end of the 18-week study showed that the intervention group had lost a mean of 2.9 kg while the control group had gained 0.06 kg.

Total cholesterol decreased by 8.0 mg/dL in the intervention group compared with 0.01 mg/dL in the control group while low-density lipoprotein (LDL)-cholesterol decreased by 8.1 and 0.9 mg/dL in the two groups, respectively.  High-density lipoprotein (HDL)-cholesterol decreased by 1.8 mg/dL in the intervention group and increased by 0.9 mg/dL in the control group. There was a 9.9 mg/dL increase in triglyceride levels in the intervention arm and a decrease of 1.4 mg/dL in the control arm.

In diabetic patients, hemoglobin A1C levels fell by 0.6 percentage points in the intervention group and 0.08 percentage point in the control group.

The differences between the intervention and control groups were significant for all measures.

“About two thirds of Americans are overweight, and about half of overweight individuals are obese,” Dr. Mishra said. “Nutritional intervention programs are needed at the worksite for both medical and financial reasons. Obesity, diabetes, cardiovascular disease, and other diet-related diseases exact a growing financial toll worldwide, much of which is borne by employers. In fact, research has shown that about 25% to 30% of medical costs incurred by employers are due to the excess risk associated with overweight, coronary disease, lipid abnormalities, diabetes, and hypertension.”

She also noted that weight reduction with a vegan diet is probably due to early satiety resulting from increased fiber intake, which produces a decrease in energy intake and a slight increase in postprandial energy expenditure from increased insulin sensitivity.

The decreases in total and LDL cholesterol that occur with vegan diets are the result of a lack of animal fat and cholesterol in such diets coupled with the lipid-lowering effect of certain plant-based foods that are typical of a vegan diet. 

Dr. Mishra cited as study strengths the inclusion of a geographically diverse population, the use of a simple intervention that can used at other corporate sites, and adequate statistical power to show significant changes. She was quick to add, however, that the study was only 18 weeks and that men were underrepresented.