March 7, 1986

Dietary Intake, the First Law of Thermodynamics, and the Properties of Yoga

Author Affiliations

Vanderbilt University School of Medicine Nashville, Tenn

JAMA. 1986;255(9):1136. doi:10.1001/jama.1986.03370090058012

To the Editor.—  The studies by Sacks et al1 concerning the relationship of vegetarian dietary habits to levels of plasma lipoproteins raise some important questions, but these studies also contain methodological problems. It seems that the data on 116 of the 132 "strict vegetarians" came from studies performed 12 years ago. Despite this, those data were pooled with modern data—a questionable practice. Body weights of the subjects were not measured—the investigators electing to use the subjects' own estimates of weight. Nutritionists are well aware of the systematic biases introduced here. The investigators say that "quantitative records of foods eaten for five consecutive days were kept," but in the next sentence they concede that "portion sizes were estimated and recorded by the subjects." That is "quantitation" with a small "q"!The most astonishing revelation is in Table 1 where 75 lactovegetarians, including 32 men and 43 women, with average body