Diminished weight loss and behavioral compliance during repeated diets in obese patients with type II diabetes.

Compared weight losses during first and second bouts of a very low calorie diet (VLCD) and examined whether decreased compliance might in part explain the decrease in weight loss during the second bout. Forty-five Type II diabetic patients participated in a year-long behavioral weight-reduction program that incorporated a VLCD (400 to 500 kcal/day) during Weeks 1 to 12 and 28 to 40. Weight losses decreased dramatically from the first to the second VLCD (15.54 vs. 1.42 kg, p less than .0001). There was also markedly diminished adherence as assessed by weeks ketonuric, attendance, and completeness of self-monitoring records. The percentage of weeks subjects were in ketosis dropped from 61% during VLCD 1 to 13% during VLCD 2 (p less than .0001). Similarly, subjects attended significantly fewer treatment meetings during VLCD 2 and self-monitored less during VLCD 2 than during VLCD 1. Weeks ketonuric and initial weight accounted for 63% of the variance in weight loss during VLCD 1 (p less than .0001); weeks ketonuric and attendance predicted weight loss during VLCD 2 (p less than .0001), accounting for 54% of the variance. These results suggest the importance of behavioral factors in explaining poorer performance on a repeated diet.