Effect of weight loss on blood pressure and insulin resistance in normotensive and hypertensive obese individuals.

In this study, the effect of weight loss on blood pressure and various facets of glucose and insulin metabolism was examined in 22 subjects with mild to moderate obesity; 11 with high blood pressure (diastolic blood pressure > 95 mm Hg) and 11 with normal blood pressure (diastolic blood pressure < 90 mm Hg). The two groups were similar in mean (+/- SEM) body mass index at baseline (30.2 +/- 1.0 v 31.6 +/- 1.1 kg/m2), and each group lost approximately 8 kg during the 3-month study period. Blood pressure fell significantly (P < .003) following the 8 kg weight loss in both the normotensive (122 +/- 3/81 +/- 3 to 110 +/- 3/74 +/- 2 mm Hg) and hypertensive (149 +/- 3/98 +/- 1 to 135 +/- 3/86 mm Hg) subjects. Furthermore, the plasma glucose and insulin responses to a 75 g oral glucose load were significantly lower (P < .001) following weight loss. Finally, insulin resistance, as assessed by determining the steady-state plasma glucose (SSPG) concentration at the end of a 180 min infusion of somatostatin, insulin, and glucose, was also lower (P < .002) after the 8 kg weight loss in the normotensive (243 +/- 23 to 172 +/- 15 mg/dL) and hypertensive subjects (266 +/- 18 to 181 +/- 25 mg/dL). Since the steady-state plasma insulin concentrations were, if anything, slightly lower after weight loss in both groups, the lower post-weight loss SSPG values actually underestimate the improvement of insulin resistance. Thus, weight loss of 8 kg in moderately obese individuals leads to significant decreases in blood pressure and plasma glucose and insulin concentrations in response to an oral glucose challenge and degree of insulin resistance.