Objectives Recent studies have shown that the prevalence of depression and obesity are rising at an alarming rate in the elderly. There is little research on the effects of weight loss on depression intensity. We aimed to investigate the effects of weight loss by physical activity and diet on depression levels of highly depressed elderly women.
Methods & Materials The information related to depression and body composition of 1265 obese elderly women (height: 160.7±3.1 cm, age: 61.6±1.8 years, weight: 81.52±1.07 kg) that were recruited in Weight Control Center of Sport Medicine Association was investigated. According to Beck Depression Inventory (BDI), 175 women who were obese and highly depressed (30.6±2.8) were divided randomly in three groups: physical activity (n=59), diet (n=59) and control groups (n=57). In the pre-test stage, all obesity variables were measured by body composition analyzer. Exercise protocol included, five-session aerobic exercise per week, each 45 min during 12 months period and with the pulse 55%-65% of maximum of heart beats. Their food regimen were de-signed based on their recommended daily intake as prescribed by the nutritionist. Their physical activity and diet programs were monitored by phone, self-report or counseling at the clinic. The post-test was performed after 12 months. 
Results The results showed that both intervention groups (respectively, physical activity and diet groups) had a better results in decreasing depression level compared to control group (P≤0.05). Further-more, the physical activity group had a better result than diet group (P=0.001, P=0.006).
Conclusion Weigh loss may lead to depression decrease especially by physical activity and a better result would be attained if visceral fat is decreased.