Background. We previously determined that a weight-maintenance, non-ketogenic diet containing 30% carbohydrate (CHO), 30% protein, 40% fat, (30:30:40) (LoBAG30) decreased glycated hemoglobin (%tGHb) from 10.8 to 9.1% over a 5 week period in subjects with untreated type 2 diabetes. Both the fasting glucose and postprandial glucose area were decreased. Our objective in the present 10-week study was to determine: 1) whether the above results could be maintained, or even improved (suggesting a metabolic adaptation) and 2) whether the subjects would accept the diet for this longer time period. In addition, protein balance, and a number of other blood and urine constituents were quantified at 5 and at 10 weeks on the LoBAG30 diet to address metabolic adaptation. Methods. Eight men with untreated type 2 diabetes were studied over a 10-week period. Blood was drawn and urine was collected over a 24 hour period at the beginning of the study with subjects ingesting a standard diet of 55% CHO, 15% protein, 30% fat, and at the end of 5 and 10 weeks following ingestion of a LoBAG30diet. Results. Body weight was stable. Fasting glucose decreased by 19% at week 5 and 28% at week 10; 24-h total glucose area decreased by 27% at week 5 and 35% at week 10 compared to baseline. Insulin did not change. Mean %tGHb decreased by 13% at week 5, 25% at week 10, and was still decreasing linearly, indicating that a metabolic adaptation occurred. Serum NEFA, AAN, uric acid, urea, albumin, prealbumin, TSH, Total T3, free T4, B12, folate, homocysteine, creatinine, growth hormone and renin did not differ between weeks 5 and 10. IGF-1 increased modestly. Urinary glucose decreased; urinary pH and calcium were similar. Conclusions. A LoBAG30 diet resulted in continued improvement in glycemic control. This improvement occurred without significant weight loss, with unchanged insulin and glucagon profiles, and without deterioration in serum lipids, blood pressure or kidney function. Extending the duration of time on a LoBAG30 diet from 5 to 10 weeks had little or no further effect on the hormones and metabolites measured, i.e. a metabolic equilibrium was established.