Although aging affects metabolism, dietary intake and healthy eating together with physical activity can help maintain ideal body weight with aging.
The composition of the human body changes during the entire aging process from development to maturation and during the advancing years. The sum of the body’s components, body weight, also fluctuates during an individual’s life span.
When these changes occur and are in excess, especially the amount of fat, then deleterious conditions such as diabetes and cardiovascular disease are manifested. Increased body fat and loss of bone mineral density and muscle mass are defining characteristics of the aging process. These changes in body composition occur as a result of normal aging and can have a detrimental impact on health status and substantial economic consequences on the health care system. Obesity is associated with an increased prevalence of co-morbidities including cardiovascular disease, type 2 diabetes mellitus, hypertension, dyslipidemia, and other metabolic diseases. The decline in skeletal muscle mass is associated with weakness, functional disability, frailty and morbidity, whereas the decrease in bone density increases the risk of bone fractures and ultimately results in high rates of disability, morbidity, and mortality in the elderly.
The latest estimates of the overall prevalence of obesity in the United States is about 42 percent, according to the Centers for Disease Control and Prevention. By age, obesity prevalence was 39.8 percent among adults 20-39 years old, 44.3 percent among adults 40-59 years old, and 41.5 percent among adults 60 and older.
From the Behavioral Risk Factor Surveillance System data set, approximately 51 percent of adults are exercising more than 150 minutes per week. Almost 40 percent of American adults consume less than one fruit per day and about 21 percent of adults report consuming vegetables less than one time daily. Eating more fruits, vegetables, whole grains, and dairy improves diet quality. In addition, cutting down on added sugars, saturated fat, and sodium will improve diet quality.
The U.S. Department of Agriculture provides nutrition information for older adults to promote healthy eating and reduce disease risk and tips to manage changes that affect appetite and eating with age. A healthier eating pattern can be achieved and suggestions include 1) enjoying a variety of foods from each food group; 2) ensuring adequate protein intake throughout the day, and adding seafood, dairy, beans, peas, or lentils to meals; 3) adding sliced or chopped fruits and vegetables to meals and snacks; 4) trying foods fortified with vitamin B12 (some cereals); 5) reducing sodium intake by seasoning foods with herbs and citrus; and 6) drinking plenty of water throughout the day to maintain hydration. Meal planning and understanding food patterns may aid older adults in their understanding of healthy eating.
Knowledge of one’s caloric intake can help determine daily calories to maintain, lose, or gain weight. An individual’s caloric needs can be estimated using one’s age, height, weight, and sex. For research purposes, measurement of resting metabolic (RMR) and activity estimates can be used to help establish individualized dietary recommendations to develop an optimal weight and energy control program. RMR is defined as the amount of energy expended by a person in a resting state under postabsorptive and thermoneutral conditions. This energy requirement reflects the necessary energy needed to sustain the body’s vital functions in the waking state, including respiration, heart rate, and blood pressure.
RMR makes up the largest component (60-75 percent) of total daily energy expenditure, which also is composed of the thermic effect of meals (TEM) (10 percent) and the thermic effect of physical activity (typically 15-30 percent but may be much higher in highly active individuals). The major factor determining RMR is fat-free mass (FFM; the body's water, bone, organs, and muscle content); whereby FFM accounts for 60-85 percent of the variance in RMR. Age accounts for up to 14 percent of the variance in RMR, and a 2 percent decrease in RMR per decade is observed throughout adulthood.
Thus, although aging affects metabolism, dietary intake and healthy eating together with physical activity can help maintain ideal body weight with aging.
Research at the Baltimore VA Medical Center is investigating resting metabolism, weight loss and weight gain, and nutritional interventions in aging populations. For more information, please contact Kristina.Marcus@va.gov or VA cell number 443-326-6165.