In a 1984 snapshot taken as he crossed the finish line of a half marathon, 40-year-old Peter Larson looked “lean and mean” at 162 pounds. Now, 20 years later, Larson weighs in at 192 pounds. So what’s changed? For Larson, like millions of aging Baby Boomers who are losing the battle of the bulge, caloric intake no longer matches energy expenditure.
To make matters worse, unwanted weight gain is only one of many health challenges the Baby Boomers face. With 64% of the U.S. population now either overweight or obese, this population is at increased risk for cardiovascular disease, hypertension, cancers of the prostate and breast, type 2 diabetes, gallbladder disease, sleep apnea and osteoarthritis. Because the number of Americans over age 65 is expected to double by the year 2030 (Kurtzweil 2001), health and fitness professionals need to learn how to help their Baby Boomer clients age healthfully and stay nutritionally fit.
Experts are divided on how much weight gain is a product of the natural aging process and how much is attributable to other variables, such as decreased energy expenditure. But one thing’s certain: Decreased physical activity results in diminished muscle mass, which in turn impacts metabolic rate, or the rate at which the body burns calories. As part of the normal aging process, most body organs decrease in functional capacity, resulting in a 2% decline in basal metabolic rate (BMR) each decade (Kurtzweil 2001). However, if physical activity also declines, BMR will decrease more quickly and there will be a greater increase in fat mass. Over time, weight gain will occur unless caloric intake is decreased.
Age-related changes that can impact metabolic rate include decreased functional capacity of the cardiovascular, gastrointestinal and respiratory systems, which can influence both nutrient absorption and nutrition needs (Williams 2003).
While we can’t stop the aging process, it is possible to maintain weight as we get older. According to William Evans, PhD, of the Donald W. Reynolds Center on Aging at the University of Arkansas, “Engaging in a regular strength and conditioning program can retain and increase lean body mass as we age” (Campbell et al. 2002). This was underscored by a study in which researchers compared the differences in lean body mass between older men and women (age 54–78) who performed 12 weeks of resistance training (RT) and their counterparts who remained sedentary (Campbell et al. 2002). The study’s goal was to determine what effects RT had on body composition, skeletal muscle size and protein metabolism in people of this age group. During the study period, all subjects ate a controlled-calorie diet that provided 0.8 grams of protein per kilogram (g/kg) of body weight per day, which is the current U.S. Recommended Dietary Allowance (RDA) for all adults. The RT group was divided into those who performed whole-body training versus those who did only lower-body RT. In both the RT groups, muscle strength increased by 17% in men and 12% in women in the muscle groups trained. Muscle strength did not increase in the sedentary group. Based on results like these, it is possible that muscle loss and decreases in BMR due to aging can be avoided—or at the very least reduced—by regularly engaging in RT.
It is interesting to note that in the study described above, both the RT subjects and the sedentary controls maintained a positive nitrogen balance, indicating that the amount of protein (0.8 g/kg) they consumed each day was adequate for muscle maintenance. Nutrition assessments have shown that older adults need at least 1 g of protein per kg of body weight to stay in positive nitrogen balance. However, the current RDA for protein is the same for all adults, regardless of age (Jenson 1998).
Eating foods that have a low nutrition value can also cause micronutrient shortages in older adults. Simply put, nutrient-dense foods are those that offer an array of valuable micronutrients while providing fewer total calories. For example, at 120 calories an English muffin made with processed white flour provides carbohydrate, a small amount of protein, B vitamins and a trace of iron. However, if that same English muffin is made with whole wheat, it has the added benefit of providing as much as 2 g of dietary fiber.
One way to help Baby Boomer clients make good food choices is to educate them about the differences in nutrient density in similar foods. By way of example, remind them that 8-ounce servings of regular and nonfat milk offer identical amounts of calcium, protein, vitamin D, vitamin A and phosphorus; however, the two versions differ significantly in terms of calorie content. For more practical suggestions, see “Nutrient-Dense Food Sources,” left.
Most health professionals know that the key to weight maintenance is energy balance, or balancing energy (calories) eaten with energy expended. Without overanalyzing why aging Americans gain weight, it’s safe to speculate that most people tend to exercise less often as they get older while still eating the same portions and foods they did when they were younger. That’s one reason why weight loss in- tervention strategies for Baby Boomers should emphasize improving health by eating smaller portions of food and focusing on nutrient density.
Additionally, an older person’s ability to lose weight may depend to some extent on who is doling out the food. One study found that adults who serve themselves tend to eat smaller portions than those who are given set amounts of food (Rolls 2002). Study participants (aged 45–63) who were served their food generally ate everything on their plates, whereas subjects who served themselves took and ate less food.
So how does this translate in practical terms to your Boomer clients who are losing the weight battle? Recommend they share entrées when dining out or ask for their meals to be divided in two, with half allocated to a “doggie bag” they can take home for the next day. Also suggest they choose restaurants that serve family-size meals and allow customers to serve themselves—but advise them to veer clear of all-you-can-eat buffets and smorgasbords! Teach your older clients that even at home, it is important to pay attention to the size of their plate, bowl and glass in order to keep track of portion size.
Other physiological factors that affect weight as we age are hormonal changes and our ability to digest food properly. While hormones decline in both men and women as we age, the lack of estrogen has a striking effect on calcium absorption in menopausal women. That’s because estrogen plays such a significant role in controlling calcium absorption and retention in the bones. Without adequate estrogen, women over the age of 50 are at increased risk for stress fractures or full-blown broken bones. However, experts do not recommend that women of this age supplement their calcium intake beyond the recommended 1,300 milligrams (mg) per day, which is the current Estimated and Adequate Intake for women over age 50. Most experts say that the source of this calcium should come from dietary food (see “Nutrient-Dense Food Sources” on page 80), but in some instances, a physician may prescribe calcium supplements. Resistance training is also an excellent way for women of all ages to stimulate bone growth. Once considered promising, hormone replacement therapy now appears to have little or no positive effect on bone mass growth.
Another thing clients need to be aware of is the role that intestinal bacteria can play in weight gain as we age. Atrophic gastritis is a bacterial infection marked by a decreased ability to produce sufficient amounts of gastric acids; this condition occurs in 24% of people aged 60–69 years, 32% of people aged 70–79 and about 40% of people over the age of 80 (Russell 2001). Low-acidic conditions in the stomach can affect the absorption of nutrients such as folic acid, vitamin B12, calcium, iron and beta carotene (Rolls 2002). Clients who suffer from atrophic gastritis are usually advised to get adequate calories by eating more small meals throughout the day or by snacking on nutrient-dense foods (e.g., carrot sticks or cherry tomatoes) between meals to prevent micronutrient shortages. Medications may also be prescribed for this condition.
Despite the promises of ads and infomercials, there is no magic pill for aging gracefully and maintaining a svelte body. In fact, the scientific literature does not even support the need for dietary supplements for Baby Boomers wanting to stay young. Instead, the old advice is the best advice: Eat a balanced diet that contains all five food groups, drink plenty of water, and get a daily dose of strength and cardiovascular exercise. In the long run, living a healthy life is the best prescription for optimal aging!