Greater hunger and less restraint predict weight loss success with phentermine treatment

Objective Phentermine is thought to cause weight loss through a reduction in hunger. It was hypothesized that higher hunger ratings would predict greater weight loss with phentermine. Methods This is an observational pilot study in which all subjects were treated with phentermine for 8 weeks and appetite and eating behaviors were measured at baseline and week 8. Outcomes were compared in subjects with ≥5% vs. <5% weight loss, and linear regression was used to identify predictors of percent weight loss. Results Twenty‐seven subjects (37 ± 4.5 years, 93.8 ± 12.1 kg, BMI 33.8 ± 3.1 kg m −2 ) completed the study, with mean weight loss of −5.4 ± 3.3 kg (−5.7% ± 3.2%). Subjects with ≥5% weight loss had higher baseline pre‐breakfast hunger ( P  = 0.017), desire to eat ( P =0.003), and prospective food consumption (0.006) and lower baseline cognitive restraint ( P  = 0.01). In addition, higher baseline home prospective food consumption ( P  = 0.002) and lower baseline cognitive restraint ( P  < 0.001) were found to be predictors of weight loss. Conclusions These results suggest that individuals reporting greater hunger and less restraint are more likely to achieve significant weight loss with phentermine. This information can be used clinically to determine who might benefit most from phentermine treatment.