By CEO Robert Forster, PT
“Most metabolisms become impaired or at least somewhat impaired with aging,” says Dr. Nik Dhurandhar, obesity researcher, Ph.D., professor and chair of nutritional sciences at Texas Tech University. He adds that such changes lead to an oft-repeated refrain among his middle-aged and older patients: My diet has been exactly the same for decades, so why am I gaining weight?
“They may, in fact, be eating exactly the same as before,” says Dhurandhar, “but they’re not accounting for their energy requirement dropping.” Since you may not need as many calories as you used to, and if you’re still eating the same way, the natural consequence is weight gain.
The term “metabolism” is shorthand for all metabolic systems with one oversimplified anthem: calories in versus calories out. This formula is responsible for your weight and body composition.
In reality we have multiple metabolisms. “Think of glucose metabolism, lipid metabolism, protein metabolism,” says Dhurandhar. For each of these separate systems, researchers have discovered multitudes of epigenetics that influence how different individuals respond to what and how much they eat, sometimes too little, and how this impacts energy expenditure, the conscious and unconscious physical activity of our human body.
As we age, each of these systems slows down.
Leslie Bonci, M.P.H., R.D.N., a Pittsburgh-based nutrition consultant whose clients include the WNBA, Kansas City Chiefs, and Pittsburgh Ballet Theatre suggests that there are a variety of reasons for metabolic slowdown. “Part of it is due to hormonal shifts over time,” she explains. “The pituitary gland’s production of growth hormone, for instance, decreases with age. Growth hormone is used to build muscle and effectively utilize fat, so as levels decrease, body composition shifts to a higher fat-to-muscle ratio.”
A related phenomenon is sarcopenia of aging. Sarcopenia is the progressive loss of muscle mass at about 1 to 5 percent a year and higher in some cases. The cause of sarcopenia remains unclear. Experts believe behavioral changes in adulthood are the main culprit. For example, adult responsibilities make for fewer opportunities to play outdoors, the inclination for constant physical activity that comes naturally to us in youth. Others blame diminishing testosterone, estrogen, and nutrient levels as a likelier cause.
No matter the cause, a metabolic shift is the result of less muscle and more fat. Not only does aging reduce our strength from muscle loss, aging slows our metabolic rate. Fat burns very few calories. It is our muscles that burn more calories even at rest.
At PHASE IV we analyze metabolic rate using the content of your respirations at rest. While we rest, all of the metabolic systems must be fueled, from controlling our body temperature and blood circulation to cell production and tissue repair. This basil metabolic rate accounts for 60 -70% of all the calories we burn. Our lean body mass is responsible for two-thirds of our B.M.R., and this varies widely between individuals. Your BMR reveals not only how many calories you burn at rest, but also whether your metabolism is slow, medium, or fast.
As body composition shifts with age, it also determines how different hormones function. Insulin, a hormone that controls blood sugar content, may also become resistant with age, and the development of diabetes is not only a concern for us as we get older, but it is also an epidemic among our obese youth. People at a healthy weight, of course, can also develop metabolic conditions. Regardless of which comes first—an unhealthy body composition or metabolic disorder—once established, the two tend to amplify each other making weight management and sustainable weight loss a complex goal.
At PHASE IV we use results driven science to shift your metabolism to burn more fat throughout the day. Contact us today 310-582-8212 to schedule your RMR Resting Metabolic Weight analysis and find out how to shift your metabolism to keep the weight off for life!