Letters Section Editor: Robert M. Golub,
MD, Senior Editor.
To the Editor: The study by Dr Pereira and
colleagues1 showed a smaller reduction in resting
energy expenditure during a low–glycemic load diet compared with a low-fat
diet in a group of patients who were obese. Although the results of the study
seem to favor the use of the low–glycemic load diet, the selection criteria
may have introduced a selection bias so that the patients were representative
of no more than 20% of the obese population. We base this on the following
3 considerations. First, the prevalence of the metabolic syndrome may be up
to 70% in obese women.2,3 In this
study, 3 of 4 patients were women, yet metabolic syndrome was not present.
Second, although a minority of people who are obese may be free of insulin
resistance, it appears that this study population did not have insulin resistance.
Third, the absence of the metabolic syndrome and the normality of insulin
sensitivity could help explain the relatively low levels of C-reactive protein
which has been found to be positively associated with the prevalence of both
obesity and the metabolic syndrome.4,5 We
are interested in knowing the waist size and the body mass index (BMI) in
this population. We believe that the poor representativeness of the study
sample with respect to the entire obese population represents a major limitation
to generalizing these findings.
Esposito K, Giugliano D. Low–Glycemic Load Diet and Resting Energy Expenditure. JAMA. 2005;293(10):1189-1190. doi:10.1001/jama.293.10.1189-a