It is a common belief that menopausal women have greater difficulty losing weight. The aim of this study was to assess the efficacy of a Mediterranean diet (MD) to promote weight loss in postmenopausal women. All participants were prescribed a hypocaloric traditional MD, tailored to the individual. Subjects were asked not to begin any kind of physical activity. Body composition was measured at the beginning and after 8 weeks of treatment. In total, 89 women (age 52.8 ± 4.5 years, BMI 30.0 ± 5.2 kg/m, fat mass 31.6 ± 10.5 kg) were divided into two groups: the first group consisted of fertile women over 45 years of age, the second group consisted of those diagnosed as menopausal. All women had an improvement in body composition (fat mass -2.3 ± 2.1 kg, < 0.001; protein -0.1 ± 0.7 kg, = 0.190) and blood pressure values. No differences were found between the two groups except for a higher reduction of low-density lipoprotein in the menopausal group ( = 0.035). A positive significant correlation between plant to animal protein ratio and fat-free mass variation was found in the menopausal group. These data suggest that a high adherence to a traditional MD would enable menopausal women to lose fat mass and maintain muscle mass with no significant difference to younger women. Fat mass reduction provides menopausal women with improved cardiovascular and metabolic risk factors.