Dietary Intervention and Varying Physical Activity in Seniors

PRO+EX and CARB+EX groups will be prescribed an exercise program with required attendance of 3 nonconsecutive days per week. Exercise sessions will be supervised and conducted by trained graduate students in the Department of Kinesiology. Based on recommended practice, a program that combines flexibility and balance activities, weight bearing endurance exercise (walking) and resistance training to preserve lean mass will be prescribed. Each session will last \~75 min with a 35 min warm-up/aerobic exercise of mild to moderate intensity, \~30 min of resistance training, and finally, a \~10 min of balance and flexibility exercises during the cool-down period. Endurance training activities will vary but will all be weight-bearing.

PRO diet recommendations will include high quality proteins with an emphasis on lean meats with protein being targeted for every meal and snack. PRO will provide dietary protein (1.6 g.kg-1.d-1; \~30% of energy intake) with a ratio of carbohydrate/protein of \<1.5 and dietary lipids at \~ 30% energy intake. Energy deficit will be determined by reducing estimated daily energy needs by \~500 kcal/d. Regarding beef intake specifically, the prescribed diet will include a minimum of one serving of beef per day, which is approximately 3 to 3.5 ounces or \~100 grams. This amount of lean cooked beef provides an average of \~25-30 grams of protein per day (www.beefnutrition.org/leanbeef.aspx). Our dietary prescription to the PRO groups that they add 3 ounces (and perhaps up to 3.5 ounces pending body size) of lean beef daily will provide an additional 25-30 grams of protein. This diet will also include 5 servings/day of vegetables and 2-3 servings/day of fruit.

For the CARB group, the diet will provide dietary protein at 0.8 g.kg-1.d-1 (\~ 18% of energy intake) with a ratio of carbohydrates/protein \> 3.5 and dietary lipids at \~ 30% energy intake. Through nutrition education and counseling we will ensure that the CARB group meets the RDA for protein for women of 46 grams per day from a variety of plant and animal sources. Again, energy deficit will be determined by reducing estimated daily energy needs by \~500 kcal/d. Additional recommendations will include 5 servings/day of vegetables and 2-3 servings/day of fruit. Beef intake will be discouraged in the CARB group.