6 function in obese, older adults [70, 71]. A recent study exam- ined the eﬀects of a 24-week multicomponent intervention compared to a Successful Aging Educational Control group on changes in mobility function in overweight, older women with moderate functional impairments. Participants in the weight loss plus exercise (WL + E) intervention condition were instructed to reduce their caloric intake by 500 to 1000 kcal/day and to attend weekly group-based counseling sessions, as well as three center-based supervised exercise sessions per week. The exercise regimen included an aerobic phase (15 minutes), a resistance-training phase (15 minutes), a second aerobic phase (15 minutes), and a cool-down phase (15 minutes). This intervention resulted in substantial improvements in mobility (i.e., increase in walking speed = 0.15 meters/second) in this high-risk population [72]. Participants in the Successful Aging Educational Control condition received weekly lectures on a variety of health topics relevant to older adults. Noteworthy, walking speed among participants in this group did not change. In a recent study, Avila et al. [54] examined the eﬀect of a 10-week moderate intensity resistance training program combined with diet-induced weight loss on body and muscle composition and physical function in obese, older adults. The combination of resistance training and diet was found to be more eﬀective than diet alone in producing fat loss, reduc- ing intermuscular adipose tissue, and improving strength. However, no diﬀerences were found between groups on measures of physical function. Another recent trial investigated the independent and combined eﬀects of dietary and exercise interventions [55]. For this 52-week study, participants were assigned to a control group, caloric restriction group, exercise group, or a caloric restriction plus exercise group. The exercise inter- vention included both aerobic and resistance training com- ponents. While physical function (i.e., Physical Performance Test) improved for all the intervention groups compared to the control group, the diet plus exercise group exhibited signiﬁcantly better physical function compared to the diet- only and exercise-only groups. Additionally, the diet plus exercise group lead to improved peak oxygen consumption, strength, balance, and gait speed compared to all other groups. These ﬁndings suggest that multicomponent weight loss interventions can signiﬁcantly improve mobility and physical function in obese, older adults. 5. Conclusions Obesity is a major health concern in most developed coun- tries. When combined with advance age, the detrimental health eﬀects of obesity are magniﬁed. These negative eﬀects manifest in poor physical performance that can be captured with a simple measurement of gait speed. The use of gait speed not only provides a marker of physical performance but also represents a strong predictor of longevity. As such, we have presented gait speed as a surrogate endpoint that estimates the eﬀect of lifestyle interventions on longevity. Importantly, there is now extensive evidence demonstrating that lifestyle interventions involving modiﬁcation of dietary Journal of Aging Research and exercise patterns are eﬀective in producing clinically signiﬁcant improvements in gait speed. While interventions emphasizing either modiﬁcation of diet or exercise have ben- eﬁcial eﬀects on gait speed, the beneﬁts are optimized with multicomponent interventions. Therefore, interventions in- volving both diet and exercise may hold the greatest potential for improving mobility and potentially increasing longevity in obese, older adults. References [1] S. Studenski, S. Perera, K. Patel et al., “Gait speed and survival in older adults,” Journal of the American Medical Association, vol. 305, no. 1, pp. 50–58, 2011. [2] M. Cesari, S. B. Kritchevsky, A. B. Newman et al., “Added value of physical performance measures in predicting adverse health-related events: results from the health, aging and body composition study,” Journal of the American Geriatrics Society, vol. 57, no. 2, pp. 251–259, 2009. [3] J. Dumurgier, A. Elbaz, P. Ducimetiere et al., “Slow walking speed and cardiovascular death in well functioning older adults: prospective cohort study,” British Medical Journal, vol. 339, pp. 1–7, 2009. [4] J. M. Guralnik, L. Ferrucci, E. M. Simonsick, M. E. Salive, and R. B. Wallace, “Lower-extremity function in persons over the age of 70 years as a predictor of subsequent disability,” The New England Journal of Medicine, vol. 332, no. 9, pp. 556–561, 1995. [5] M. Cesari, “Role of gait speed in the assessment of older patients,” Journal of the American Medical Association, vol. 305, no. 1, pp. 93–94, 2011. [6] K. M. Flegal, M. D. Carroll, C. L. Ogden, and L. R. Curtin, “Prevalence and trends in obesity among US adults, 1999– 2008,” Journal of the American Medical Association, vol. 303, no. 3, pp. 235–241, 2010. [7] S. D. R. Harridge and A. Young, “Skeletal muscle,” in Principles and Practices of Geriatric Medicine, pp. 898–905, Wiley, London, UK, 1998. [8] R. N. Baumgartner, P. M. Stauber, D. McHugh, K. M. Koehler, and P. J. Garry, “Cross-sectional age diﬀerences in body com- position in persons 60+ years of age,” Journals of Gerontology Series A, vol. 50, no. 6, pp. M307–M316, 1995. [9] G. B. Forbes, “Longitudinal changes in adult fat-free mass: in- ﬂuence of body weight,” American Journal of Clinical Nutri- tion, vol. 70, no. 6, pp. 1025–1031, 1999. [10] R. Roubenoﬀ, “Sarcopenic obesity: the conﬂuence of two epidemics,” Obesity Research, vol. 12, no. 6, pp. 887–888, 2004. [11] T. W. Buford, S. D. Anton, A. R. Judge et al., “Models of accelerated sarcopenia: critical pieces for solving the puzzle of age-related muscle atrophy,” Ageing Research Reviews, vol. 9, no. 4, pp. 369–383, 2010. [12] W. J. Evans, “Skeletal muscle loss: cachexia, sarcopenia, and inactivity,” American Journal of Clinical Nutrition, vol. 91, no. 4, 2010. [13] R. N. Baumgartner, “Body composition in healthy aging,” Annals of the New York Academy of Sciences, vol. 904, pp. 437– 448, 2000. [14] C. S. Blaum, Q. L. Xue, E. Michelon, R. D. Semba, and L. P. Fried, “The association between obesity and the frailty syn- drome in older women: the Women’s Health and Aging Studies,” Journal of the American Geriatrics Society, vol. 53, no. 6, pp. 927–934, 2005.