Most people think gaining fat is a given as they grow older, but it can be prevented with a smart diet and regular lifting that maintains muscle. Strength training is a priority over walking or other steady-state forms of aerobic exercise, which lead to the loss of muscle over the long run.
Studies estimate that aerobic exercise results in an average loss of 4 to 6 pounds every decade, which translates to a drop in metabolic rate of 2 to 3 percent. Since no one lowers their calorie intake to correspond to the decrease in energy expenditure, they gain fat and experience deterioration of physical function as their percent body fat increases.
A new study illustrates this effect. Researchers at Wake Forest University tested the impact of different exercise protocols combined with diet on body composition changes in overweight adults in their 60s. The participants were put on the same diet that reduced calories by 330 a day below what was needed to maintain their body weight. The macronutrient breakdown of the diet was 25 percent protein, 30 percent fat, and 45 percent carbs. They were then randomized into three groups:
A strength training plus diet group that performed a typical hypertrophy-style workout four days a week for 45 minutes a session at an intensity of 75 percent of the 1RM.
An aerobic training plus diet group that walked briskly for 45 minutes four days a week at an intensity of 12-14 on the Borg RBE scale.
A control group that dieted but did no additional exercise.
Results showed that after 18 months the strength training plus diet group had by far the best results, losing more body fat and less muscle mass than the other two groups. The strength training group lost about 17 pounds of fat and only about 2 pounds of lean mass. The aerobic training group also lost a significant amount of fat, shedding 16 pounds, but they also lost 4 pounds of muscle. The control group that did no exercise lost about 10 pounds of fat and 2 pounds of muscle.
The percentage of muscle mass lost was 20 percent in the aerobic training group, 16 percent in the diet alone group, and 10 percent in the strength training group.
The study authors highlight the negative impact of losing muscle mass for older adults: Not only is it unlikely that people over 50 who lose muscle will ever gain it back, but the drop is associated with declines in strength and mobility—a combination that will increase risk of chronic pain and reduced ability to move due to increased arthritis and a loss of strength in the muscle that stabilizes joints. Additionally, when weight fluctuates, older adults are more likely to regain fat rather than muscle, further compromising body composition.
This doesn’t mean that aerobic exercise should be avoided. Rather, it’s important for older adults to incorporate both anaerobic and aerobic modes with a combined strength and cardio exercise program. Additionally, there are cardio options that will reduce the loss of lean mass when dieting: Training with resistance, such as by walking on an incline, doing stair climbing, or cycling on a resisted bike will reduce the loss of muscle from cardio. Doing intervals that alternate higher intensity efforts interspersed with active recovery can also help preserve muscle during fat loss.
Eating high-quality protein is also important. A second study from the same research group found that using a high-protein, calorie restricted diet is effective in allowing older, overweight subjects to lose significant body fat, while helping preserve lean body mass and mobility. This study showed that a protein intake between 1.2-1.5 g/kg of protein a day improved fat loss and decreased the loss of muscle.
Why is protein so important for optimizing fat loss? Protein provides amino acid building blocks that stimulate protein synthesis, helping repair lean tissue and attenuate the body’s natural inclination to breakdown muscle for energy when calories are restricted.
When it comes to what you eat when losing fat, it’s also important to load up on colorful vegetables and healthy fat. Planning meals to incorporate leafy greens, cauliflower, broccoli, avocado, nuts, olives, etc., will improve your overall nutritional profile and help you stay on track with calorie targets since these foods are satiating and less energy dense than processed food alternatives.
Older adults who want to improve their bodies should prioritize strength training in order to preserve muscle, while losing fat.
Ensuring you get a high-quality protein intake as part of a healthy diet will enhance body composition changes as you age.
Choose aerobic modes that protect lean mass by training against resistance or doing an interval style protocol in which you alternate vigorous efforts with active recovery.
Beavers, K., et al. Effect of an Energy-Restricted, Nutritionally Complete, Higher Protein Meal Plan on Body Composition and Mobility in Older Adults With Obesity: A Randomized Controlled Trial. The Journals of Gerontology. 2018. Published Ahead of Print.
Beavers, K., et al. Effect of Exercise Type during Intentional Weight Loss on Body Composition in Older Adults with Obesity. Obesity. 2017. 25(11), 1823-1829.