Background & aims: Starvation decreases insulin sensitivity and glucose tolerance in both lean and obese (OB) non-diabetic subjects. Influence of drastic calorie reduction on insulin resistance in patient with type 2 diabetes (T2DM) is not known.
Methods: We enrolled 10 T2DM (diabetes duration 11.1+/-7.9 years) and 10 OB age and weight-matched subjects and performed isoglycaemic hyperinsulinaemic clamp (two 120 min phases of 60 and 120 mIU min-1 m-2 i.v. insulin) with indirect calorimetry at baseline and after 60 h of fasting.
Results: After starvation insulin-mediated glucose disposal decreased significantly in both hyperinsulinaemic phases in T2DM (phase 1: from 46+/-28 to 33+/-17, P<0.04; phase 2 from 122+/-47 to 80+/-30 microg kg-1 min-1, P<0.01) as well as in OB (phase 1: from 94+/-52 to 52+/-24, P<0.04; phase 2: from 131+/-46 to 106+/-43 microg kg-1 min, P<0.01). Both oxidative and non-oxidative components of glucose disposal tended to be reduced after fasting. A change of insulin sensitivity was found to be highly dependent upon pre-starvation conditions: more insulin resistant subjects tended to maintain (or modestly improve) insulin resistance whilst subjects with better insulin sensitivity tended to worse it.
Conclusion: Insulin sensitivity worsens similarly in both T2DM and OB subjects during 60-h fast. The change is probably predictable according to pre-starvation insulin sensitivity.