Dietary Intervention and Varying Physical Activity in Seniors

Summary

The prevalence of obesity continues to increase at an alarming rate for all sectors of the population in the US. Obesity in the older adult cohort is of great concern as it is associated with reductions in mobility, declines in physical performance and increased risk for physical disability. With regard to body composition, a) fat mass has been determined to be a stronger predictor of mobility limitations than low muscle mass in older individuals and alternatively, b) leg lean mass has also been cited as a primary determinant of lower extremity physical function.

Obesity is related to increased levels of fatigue and lack of motivation and mental energy. Fatigue can be categorized as both a subjective perception and a performance decrement. Fatigue can be defined as a perceived lack of physical or mental energy while fatigability is another construct categorized by the degree of fatigue associated with activity in any dimension (i.e. physical, mental, emotional, and/or social).

The impact of a higher protein diet on muscle quality, muscle fatigability, perceptions of fatigue and systemic inflammation in older adults has not been well documented. The utility of a higher protein weight loss diet combined with resistance exercise training to augment fat mass loss, attenuate lean mass loss and improve muscle quality and physical function could potentially be of high value to overweight older women. The potential further benefits of this regimen to enhance mental energy and other aspects of psycho-social well-being are unknown.

The aims of the present study include assessing the effects of the proposed diet and exercise intervention on 1) body composition, 2) strength and muscle quality, and 3) energy and fatigue symptoms.

Conditions

• Obesity

Interventions

BEHAVIORAL

Exercise

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.

BEHAVIORAL

Higher Protein Diet

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.

BEHAVIORAL

Conventional Carbohydrate Diet

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.

Sponsors & Collaborators

• University of Georgia

  lead OTHER

Principal Investigators

• Ellen M Evans, PhD · University of Georgia

• Rachelle M Acitelli, MS · University of Georgia

• Chad R Straight, MS · University of Georgia

• Alison C Berg, MS, RD · University of Georgia

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

65 Years

Max Age

80 Years

Sex

FEMALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2013-01-01

Primary Completion

2014-12-31

Completion

2015-07-01

Countries

• United States

Study Locations