Psychological factors have been postulated to be involved in the success of weight reduction programs. We here demonstrated that the attachment style of participants had an effect on the success of a multi-factorial lifestyle intervention in terms of weight reduction.
That insecure attachment was not more common among the obese patients in this study than has been reported in non-clinical individuals (securely attached: 60%; preoccupied: 17% dismissing: 23% ) suggests that obesity did not affect the occurrence of different attachment styles. But, there could be a selection bias. In a study with anorectic and bulimic patients Goodwin & Fitzgibbon  showed that insecurely attached eating-disordered patients often decline an outpatient treatment offer, which would also explain the high percentage of securely attached patients in our random sample: Insecurely attached subjects do not enroll in such a one-year group program in the first place. Therefore, our study was not representative, since voluntary participation has certainly biased results.
The sex ratio of our random sample of 91% women and 9% men approximately coincides with that of treatment-seeking obese populations reported in literature (85% women and 15% men; ). This could be attributed to treatment motivation being determined by social rejection, which applies mainly to obesity in women. The largest age group in this study comprised 40 - 59-year-olds. These individuals may have a stronger desire to lose weight. Another reason could be that they are more able and willing to afford the participation costs.
Compliance to weight reduction programs is usually poor in obese individuals and therefore they often regain weight . Thus improved compliance might contribute to the therapeutic effect in those individuals with secure attachment style. This assumption is supported by the finding that the patient-therapist relationship was assessed to be more positive in secure compared to insecure participants. Indeed, previous publications confirmed that securely attached adults are considerably more cooperative in a patient-therapist situation . This corresponds to observations indicating that securely attached individuals have better access to their emotions and eating habits, can therefore better perceive, understand and name them, and thus also have better prerequisites for successful weight reduction . Individuals with an insecure attachment style are more likely to have problems with these issues; in the case of emotional entanglement, for example, preoccupied attached individuals do not perceive eating as an attempt to compensate. Dismissively attached individuals, on the other hand, tend to have difficulties in experiencing emotions and thus compensate by eating; in the case of therapeutic failure, they tend to blame others - in this setting the therapist.
It may be assumed that insecurely attached patients have difficulties in coping with the disease and also with time-limited therapies . Thus the limited number of group therapy sessions offered in our setting might have negatively affected especially preoccupied attached patients, while securely attached patients were more stable in this respect. In addition, different reactions of the therapists, which are well known to occur and may have been induced by the patients' attachment style , may also have affected differences in weight loss.
Some limitations of our study should be mentioned: For estimating the distribution of attachment styles in representative, non-therapy seeking obese individuals compared to normal weight individuals, our study results are not representative and further studies are required. This trial was a clinical outcome study, it was not randomized and there was no control group. Predominantly women were studied; thus, the results can not be transferred to male subjects. Due to the small number of cases, we did not analyze the subgroups of binge eating, night or emotional eaters, and the effect of additional psychiatric co-morbidities in this study. To estimate the relevance of attachment styles according gender, age, and different subgroups, future studies are desirable. But there is a strong support for the assumption that the attachment style and the helping alliance between patient and physician are important in the therapy of obesity and probably other diseases.