Several times a week I have conversations with clients about metabolism, how to speed it up, what can slow it down, and ways to boost it. There are some things that we can’t control when we talk about metabolism though...age, sex, and genes. When we get older, our metabolism tends to slow down because we naturally lose muscle, 5% each decade after 40, in fact. Men, who naturally have a higher ratio of muscle to fat, tend to burn up what they eat faster than women. Genes play a role as well. You are born with a certain body type. Some people just burn more calories than others.
Let’s get technical here, for a second, so that we can try to fully understand metabolism. Metabolism is the way your body converts the food and drink you consume for energy and is usually measured in calories. The total amount of calories a person burns per day is known as total daily energy expenditure (TDEE) and it comes from several sources including resting metabolic rate (RMR), the thermogenic effect of food (TEF), non-exercise activity thermogenesis (NEAT), excess post-exercise oxygen consumption (EPOC), and exercise (Ex).
TDEE = RMR + TEF + NEAT + EPOC + Ex
RMR is the number of calories your body burns, at rest, per day. TEF is the amount of energy required to digest and process the food you eat. An apple requires way more energy to break it down than a bowl of ice cream does, for instance. RMR and TEF are relatively constant and only fluctuate if you gain or lose muscle or with dietary shifts. NEAT (the energy expended for everything we do that is not sleeping, eating, or exercise), EPOC (a measurably increased rate of oxygen intake following strenuous exercise ***the afterburn effect***), and Ex have large variability and can greatly influence caloric burn.
Male – (9.99 x weight in kilograms) + (6.25 x height in centimeters) – (4.92 x age) + 5
Female – (9.99 x weight in kilograms) + (6.25 x height in centimeters) – (4.92 x age) – 161<