A Vegetarian Dietary Pattern as a Nutrient Dense Approach to Weight Management: An analysis of the National Health and Nutrition Examination Survey

A Vegetarian Dietary Pattern as a Nutrient Dense Approach to Weight Management: An analysis of the National Health and Nutrition Examination Survey 1999-2004. Bonnie Farmer, Brian T. Larson, Victor L. Fulgoni, Alice Rianville, George Liepa

The purpose of this study was to determine whether a vegetarian diet plan may be an appropriate approach for weight management. Previous research showed evidence that vegetarians tend to have a lower BMI than nonvegetarians. Through research energy intake of vegetarians was found to be about 464 calories lower per day than non vegetarian diets. This number is very close to the 500 calorie suggestion to subtract per day for weight control. This study also examined the adequacy of a vegetarian diet by looking at diet quality in order to determine if public perception that vegetarian diets are deficient in certain nutrients was shown to be true. Research shows that the general public believes vegetarian diets are deficient in protein, calcium, iron and vitamin B 12. The authors of this study decided to evaluate this possible misconception along with how adequate a vegetarian diet plan would be for weight loss compared to nonvegetarian diets that subtracted 500 calories per day for weight management.

Data from the National Health and Nutrition Examination Survey from 1999-2004 was used for this study. The NHANES study is an annual survey done to obtain health and nutrition status of the US population. The dietary recalls for the NHANES survey are collected through multiple 24 hour recalls. In order to determine diet quality the United States Department of Agriculture's Healthy Eating Index 2005 was used. Scores were given for 9 dietary components, total fruit, whole fruit, total vegetables, dark green and orange vegetables, total grain, whole grain, milk products, soy beverages, and meat, beans and soy groups. Three other scores were given to evaluate diet quality, saturated fat and sodium, solid fats and alcohol, and added sugar. Based on My Pyramid's recommended intakes per 1,000 kcals a total score was given to measure overall diet quality for each participant.

Participants for the study were adults aged 19 and older who had completed the NHANES survey with reliable dietary records (records that had not been fully completed past a certain step in the NHANES survey were excluded from the study). Pregnant and lactating women were also excluded giving a sample size of 13,292 (12,441 non vegetarian, 851 vegetarian). Vegetarians were defined as participants who did not report eating meat, including fish, on the day of the survey. If the calorie consumption for the individual was 500 calories less than their Estimated Energy Requirement, the participant was classified as a dieting vegetarian or nonvegetarian. Data was analyzed through SAS software, variance was used to compare BMI, 1 day nutrient intakes, MyPyramid equivalents, and HEI scores for vegetarians, nonvegetarians and dieting vegetarians and dieting nonvegetarians.

Results showed that the mean BMI of the vegetarian group was lower than that of the nonvegetarian group. Fiber intake was 24% higher and calcium intake was 17% higher for vegetarians than nonvegetarians. Vegetarians also had higher recorded intakes of magnesium, iron, vitamin A, C, and E, thiamin, riboflavin and folate. Total protein, total fat, saturated fat and cholesterol intakes were lower in vegetarians. Niacin, vitamin B-12 and zinc intakes were lower for vegetarians. Both vegetarians and nonvegetarians had a sodium intake above the recommended 2,300 mg limit through the DRI and Dietary Guidelines for Americans, although the vegetarian group had a lower intake comparatively. Vegetarians consumed twice as many whole grains and legumes as nonvegetarians. There was no difference in total vegetable intake between the two groups, however there was a difference in distribution of vegetables. The vegetarians ate more dark green vegetables and the nonvegetarians ate more potatoes. Comparison between the dieting groups showed that fiber intake was higher for dieting vegetarians than dieting nonvegetarians. Potassium intake was lower for dieting vegetarians, however both groups did not meet the 4,700 mg adequate level. Protein, cholesterol and total fat intakes were lower for dieting vegetarians.

The authors concluded that a vegetarian diet is consistent with the current dietary guidelines, and not consistent with the public's misconceptions. The article does acknowledge that since the study only looked at 1 day of food intake, it cannot be used to assess dietary adequacy, only diet quality. This study showed that a vegetarian diet could be used for weight control. The one nutrient that the author suggests based on this research for more education to vegetarians would be for zinc. The author does suggest that there may be a point in calorie level where if the vegetarian has restricted calories too much, they will no longer be meeting recommended levels of nutrients.

Farmer, B., Larson, B.T., Fulgoni, V.L., Rianville, A., Liepa, G. (2011). A Vegetarian Dietary Pattern as a Nutrient Dense Approach to Weight Management: An analysis of the National Health and Nutrition Examination Survey 1999-2004. Journal of The American Dietetic Association, 111 (6), 819-827.