Over the years, the tools we use for anthropometric assessments for weight management have improved tremendously. These tools provide us with much more accurate information than using predictive equations or estimations.
The term anthropometric refers to comparative measurements of the body. Anthropometric measurements are used in nutritional assessments. Anthropometric measurements used for adults usually include height, weight, body mass index (BMI), waist-to-hip ratio, and percentage of body fat. These measures are then compared to reference standards to assess weight status and the risk for various diseases. Anthropometric measurements require precise measuring techniques to be valid.
I have been using an indirect calorimeter for about 10 years to measure resting energy expenditure (REE), or resting metabolism. The device measures CO2 production and O2 consumption and converts that measurement into calories. As I explain to my patients, it is the amount of calories your body burns in a day just to run your body at rest. Or as one of my patients said, “The calories just to be.”
At the baseline REE, I often have patients tell me they believe a large part of their weight problem is due to a slow metabolism, and for some, this is the case. For those people with extremely low metabolic rates, I refer them to their PCP for thyroid testing. But for most, I discuss the factors that influence metabolic rate and how they can improve it.
Factors that affect metabolic rate and are out of your control.
· Age. Your metabolic rate declines as you age due to the natural loss of muscle mass that comes with aging.
· Gender. Women have lower metabolic rates than men because women genetically carry more fat than men. Men have more muscle mass and therefore burn more calories. So ladies, do not compete with men when it comes to weight loss.
Things you can do to help maintain or increase your metabolic rate.
· Hands down, the best thing you can do is exercise. Cardio activity will raise your metabolic rate while you are exercising and for several hours after. But, it is the muscle building, or strengthening activities, that will keep your rate higher for 24 hours. Muscle burns more calories than fat, so more muscle mass means a higher metabolic rate. The muscle building activities help prevent the natural loss from aging. In addition, when you lose weight, especially rapid weight loss that comes from weight loss surgery, you don’t lose just fat. Part of that weight loss includes muscle mass. Faithfully doing strength training can help preserve lean body mass during weight loss.
· Get enough sleep. If you consistently burn the candle on both ends, it will slow down your metabolism.
· Eat often enough. This is not grazing! This is eating every 2 to 3 hours. At eating times, choose healthy foods that include protein since protein requires your body to burn more calories to utilize than carbs or fat. Avoid eating one, large meal a day as this can slow down your metabolic rate.
There are some foods that may help you increase your metabolism. There is a compound in green tea, ECGC, and a compound in peppers, capsaisin, that can produce rather small increase but at this time the research shows they do not significantly affect weight loss. Caffeine does increase metabolism, but again, there is not enough research to support its benefits for weight loss.
At repeat REE measurements I have seen patients significantly increase their metabolic rate with large weight losses after bariatric surgery. How do they do it? EXERCISE! The best way to maintain or increase your metabolism is through exercise, both cardio and strength training.