Efficacy of dietary regulation in primary health care patients with hyperglycaemia detected by screening.

The efficacy of dietary regulation was examined in 38 consecutive primary health care patients with hyperglycaemia detected on screening. Ten weeks of dietary regulation reduced overall mean fasting blood glucose from 8.2 to 6.5 mmol l-1. Fasting blood glucose fell more (from 12.3 to 7.6 mmol l-1 and from 8.4 to 6.6 mmol l-1) in the two quartiles initially above the median (7.15 mmol l-1), than in the lower quartiles (6.7 to 6.1 mmol l-1 and 5.7 to 5.8 mmol l-1), even though weight reduction was similar. The reduction in blood glucose correlated (r = 0.87) with the degree of fasting hyperglycaemia before treatment. Sixteen patients (42%) reached or maintained fasting blood glucose less than or equal to 6.0 mmol l-1, and they had a milder degree of glucose intolerance, a higher insulin response to a meal and a greater reduction in weight than the 22 patients (58%) who did not reach less than or equal to 6.0 mmol l-1. Nine patients (24%) maintained fasting blood glucose less than or equal to 6.0 mmol l-1 for greater than 5 years, and showed a considerable improvement of insulin action. Dietary regulation improved glucose control mainly by reducing fasting hyperglycaemia; neither the delay in early insulin release nor the associated elevation and prolongation of the post-prandial glucose excursions were reduced.