Background

Some metabolic and bariatric surgery (MBS) patients have unrealistic weight loss expectations that can undermine MBS satisfaction and outcomes. Few studies have focused on relative frequency and implications of positive discrepancy between expected and actual weight loss (WL). This study compared early WL of MBS patients who had a positive (better than expected) versus negative (i.e., worse than expected) WL discrepancy.

Methods

Adult MBS patients (n=83; RYGB/n=41, SG/n=42) reported 3-month postoperative weight expectations preoperatively. Discrepancy between expected and actual weight loss (kg) was calculated for each participant. Analysis of Covariance (ANCOVA) examined association of positive/negative weight loss discrepancy with percent weight loss (%WL).

Results

Overall discrepancy between expected (14.98 kg) and actual (16.54 kg) WL was non-significant (M=1.56+-12.02 kg, p=.24). RYGB and SG participants had similar discrepancies (2.49+-13.59 kg vs. 0.65+-10.34 kg, p=.21). Among all participants, 48(58%) had a positive discrepancy (M=9.42+-6.72 kg) whereas 35(42%) had a negative discrepancy (M=-9.22+-8.91 kg). %WL was greater in participants with positive versus negative discrepancy (17.91+-5.76% vs. 7.27+-5.29%, p<.001) controlling for demographics and surgery type.

Conclusions

MBS patients on average had realistic early WL expectations, although there was variability in direction and amount of WL discrepancy. Participants with a positive discrepancy experienced ~10% greater WL relative to those with a negative discrepancy. Future research should involve both longer-term patient follow-up to determine durability of this association and whether teaching patients to develop more modest WL expectations can improve WL and other outcomes (e.g., treatment satisfaction, health-related quality of life).