Diet and Exercise Interventions to Increase Muscle Strength and Function:A Randomized Controlled Trial

Sarcopenia, the loss of skeletal lean mass and muscle strength, occurs in elderly but also may be present in obese individuals due fat infiltration of the muscle. Loss of lean mass along with fat infiltration into skeletal muscle causes decreased muscle density, which contributes to decline in muscle function. Increases in muscle density are expected to improve muscle function as well as metabolic function. This study will test the effects of a healthy diet & walking (Controls) compared to a healthy diet, walking, and balance/strength exercises (Intervention) on muscle density in two populations: elderly individuals and obese individuals. The intervention will be 3 months in length. The Control group will walk 5 times per week for at least 10 minutes/day at the start of the study and build to 30 minutes/day by the 3-month time point. The Intervention group will walk two times per week using the same criteria, and in addition will do balance/strength exercises on three days per week. At 3 months, the control group will be invited to add the balance/strength exercises.

Study visits at baseline, at intervention completion (3 months), and at a follow-up (6 months -3 months after completion of the intervention) will include: questionnaires; anthropometric measures, body composition, muscle density and trabecular bone measures; muscle function and strength testing; activity measures; diet recall; metabolic measures (waist circumference, blood pressure, fasting blood sugar, triglyceride, HDL cholesterol); and erythrocyte sedimentation rate (see Outcome Measures below for detailed measures).

Healthy Diet Education Sessions: USDA's MyPlate, was introduced in 2010, as the new guidelines for proper dietary nutrition. These guidelines, developed by the USDA in conjunction with the Department of Health and Human Services are designed to serve as the "cornerstone of Federal nutrition policy and nutrition education activities" (USDA Dietary Guidelines, 2011). Each week participants will attend a healthy diet education session based on MyPlate Dietary Guidelines. Dr. Holm will oversee the lessons that will be developed and implemented by SDSU Health and Nutritional Sciences students. Twelve lessons will be given and cycled over 3 month periods so that no matter when a participant enters the study, the same twelve sessions will be completed as they go through the study program. Focus of the sessions will be on topics such as portion size, reading food labels, calorie intake and burning, tips for grocery shopping, healthy recipes, food groups, healthy fats, carbohydrates and proteins, etc. Each lesson will take approximately 20 minutes with a group activity session to follow.

Exercise Interventions:

Control Group - The exercise intervention for the control group is walking. Walking will be expected to be completed 5 days per week and done at the participant's physical ability/pace. At the start of the study, the participant will complete at least 10 minutes per day or more according to their physical ability. By the end of the study, this is expected to increase to 30 minutes of walking each day and can be completed in 10-minute intervals throughout the day. One day per week, the control group participants will be invited to do a 'group walk' that will be on the same day of the week following the dietary education lesson. Participants will keep weekly walking logs to record the time they walk each day for the purpose of exercise, not as part of daily activities. Weekly logs will be collected and a new one issued each week during the dietary education lesson. Exercise compliance will be calculated using these logs.