Little is known about the effects of weight loss on diastolic function. Furthermore, it is not known whether both caloric restriction (CR)- and exercise (Ex)-induced weight loss have salutary effects on diastolic function. Therefore, we assessed the effects of yearlong CR (n = 12) and Ex (n = 13) interventions, which induced approximately 12% weight loss, on diastolic function in healthy, nonobese (body mass index = 23.5-29.9 kg/m2) men and women aged 50 to 60 yr. Recordings of Doppler transmitral flow and Doppler tissue imaging were acquired and analyzed by conventional approaches and a validated parameterized diastolic filling (PDF) formalism. Isovolumic relaxation time decreased after weight loss in both groups (P < 0.05). Septal peak early mitral annular velocity (E') increased (P < 0.01) and peak E-wave velocity/E' decreased (P < 0.05) after weight loss in the CR group. Based on the PDF-derived indexes, CR resulted in a decrease in global ventricular stiffness (k) and increases in longitudinal (septal annulus motion) stored elastic strain (chi'o), peak force (k'chi'o), and peak stored strain energy (1/2k'chi'o2). In the Ex group, k was unchanged, although septal chi'o and 1/2k'chi'o2 increased significantly and k'chi'o (P = 0.13) tended to increase. We conclude that weight loss, whether induced by CR or Ex, has salutary effects on diastolic function.