Defining metabolismWhat is your metabolism? It’s any of the physical processes in your body that covert and use energy. This includes digesting foods, eliminating waste, breathing, pumping blood, moving your muscles, controlling your body temperature and nerves, and thinking. Yes, thinking uses energy!
Here are a few more definitions:
BMR or RMR: Basal Metabolic Rate, also called Resting Metabolic Rate. This is the number of calories you need if you stayed in bed and slept all day. It’s the minimum needed to keep your body going.
TDEE: Total Daily Energy Expenditure. This is the number of calories you burn throughout the day if you actually get up out of bed. It’s the BMR plus the number of calories burned by walking, running for the bus, lifting weights, fidgeting, going back and forth to the printer to see if your report is done printing yet, doing cardio, and so on.
What about the “speed” of your metabolism?People talk about having a fast or slow metabolism, and about “speeding up” their metabolism (if they want to lose weight), or “slowing down” their metabolism (if they’re trying to gain weight). However, your metabolism—metabolic rate (BMR), is largely governed by four things: your size, your age, your gender, and genetics.
SIZE. The larger you are, the more calories you burn. Overweight people often complain that they have “slow” metabolisms, but in reality they burn
more calories than someone who weighs less. It takes energy to sustain weight, and energy comes from calories burned.
AGE. Children and teens who have not finished growing will require differing amounts of calories, depending on what stage of growth they’re in. Teens going through puberty, especially boys, may need a great many more calories than they (or their parents) think. As people get older, they naturally burn fewer calories, which is mainly due to a slow loss of muscle mass—less muscle mass means fewer calories are burned.
GENDER. Men usually have more muscle and less fat than women. A man who’s the same height and weight as a woman will burn more calories because he has proportionally more muscle.
GENETICS. Some people are born with a higher BMR than others; others burn calories more slowly. However, on AVERAGE, in general, for an adult over age 21, their BMR will be close to the same as any other adult of the same age, gender, and size. A great deal of research is behind those on-line “calories needed” calculators. But because it IS an average taken from a large number of people, if you’re looking at one individual, there will be normal variation from the calculated BMR.
How much control do you have over your metabolic rate?GAIN MUSCLE. Muscle is active tissue, and needs energy to be sustained. Energy is provided by burning calories. There are varying claims about how many calories a pound of muscle burns, from 6 extra calories a day to 50. Part of the problem in this estimate is that the methods used to measure body composition and metabolic rate are not always the same, there can be measurement error, and the different methods are not all similarly accurate.
Several recent research projects by experts in genetics, obesity, and biochemistry shows that a pound of muscle burns about 6 calories a day. Studies have also shown that the more muscle you have, the more calories you’ll burn after an
intense workout. This is supported by the research on high intensity interval training (HIIT), which finds that athletes who do HIIT have a greater lean body mass than athletes who do only steady-state cardio.
What it comes down to, though, is that having more muscle
will enable you to burn more calories. My theory is that this number—whether it’s 6 or 50—will vary for each individual, just as the BMR varies by individual.
INCREASE YOUR ACTIVITY. The best way to “speed up” your metabolic rate—how many calories you burn—is to increase how much activity you do. Cardiovascular exercise is the primary way to burn calories, although there are many ways to increase your activity. Fidget during a boring class or meeting, pace when you’re talking on your cell phone or waiting for the bus, park your car farther away in the parking lot, use the stairs instead of the elevator… even getting up to change the TV channels instead of using the remote control can burn more calories!
A measure of how good your activity is at burning calories is your heart rate. Note that it isn’t the heart rate itself that burns calories; it’s the activity you do to increase your heart rate. You have to actively use your muscle to burn more calories. A totally different body mechanism increases your heart rate when you’re excited or scared. Sitting in front of the TV and having your heart rate increase because you’re watching Zombieland does NOT burn more calories (unless you get up and kill off a few zombies yourself!)
The “set point” theory of metabolic rateThe “set point” theory has been around for decades. Basically, this theory postulates that each individual has a pre-determined set point for body weight. If a person goes above or below this set point, the body’s metabolic mechanisms will change to bring them back to the set point weight. This is a great excuse why people are overweight and can’t lose weight (or why thin people can’t gain weight), but it’s not supported by research. What’s more likely is that nutrition and activity habits, cultural pressures (both good and bad), other environmental factors,
and the individual’s BMR are responsible for body weight.
Losing weight… and gaining weightThe topic of metabolism and metabolic rate most commonly comes up because people want to lose weight (lose fat). We have many good videos that address this in our Video Library.
Less often do we hear about people who want to
gain weight. Most often, this lament comes from teenagers, who are still growing and who want to add muscle. It’s very difficult to determine the TDEE for a growing teen; the number of calories they need can vary from month to month, depending on what stage of puberty they’re in. Adding muscle mass usually occurs toward the end of puberty, and not soon enough for the teen. Height growth often comes first, causing the teen to despair over adding any muscle.
If this is
you, the best way to try to gain weight is first to calculate your TDEE, repeating this often as you grow in height and weight. When calculating this, try to pick the level of activity closest to what you actually do. Next, get an accurate idea of how
many calories you actually eat. Teens are often on-the-go, and you may not take the time to eat a full meal, you might not be able to eat as often as you’d like at school—or you may not feel hungry. If you’re already eating at or above your TDEE (don’t just guess, take some time to actually figure it out), then increase your intake of healthy food by about 200-300 calories a day.
Keep track of your progress by taking pictures of yourself, as often as every two weeks. The scale is not a useful gauge of progress when you’re growing in height as well as adding weight. You want to adjust your daily calories to support your growing body and growing muscles, but not add fat. If you see no progress in two weeks, increase the number of calories you eat again—and again take a picture after two weeks. Even though teens have the capacity to add muscle at a fast rate, it’s not an overnight process, so be patient!
Some people say that teens shouldn’t worry about what they eat; because they’re growing, they can eat any sort of junk, so long as they get the calories. However, even very lean people can get sick from an unhealthy diet, so it’s really best to add calories from healthy food—food that will give you the protein, fiber, carbs, and vitamins your growing body needs.
Final wordThere are a few, rare medical conditions that effect metabolism and the ability to gain or lose weight. If you have a good understanding of your calorie intake and calories burned, and it seems like something is not right, go see a doctor.
PLEASE GO HERE ---> Metabolism to comment on this topic!USEFUL LINKS:
Video Library: Cardio and Losing WeightNutrition and MetabolismCalories Needed CalculatorNutrition Data and CaloriesCardioThe Truth About the Fat Burning Zone and Heart RateREFERENCES:
National Institute of Health: MetabolismWebMD: Make the most of your metabolismMayo Clinic: MetabolismThe Myth about Muscle and Your Metabolic RateThe underappreciated role of muscle in health and diseaseDo adaptive changes in metabolic rate favor weight regain in weight-reduced individuals? An examination of the set-point theory. Role of Environmental vs. Metabolic Factors in the Etiology of Obesity: Time to Focus on the EnvironmentHow to Gain Weight With a Fast MetabolismHow Your Metabolism Really Works I can't gain weight! Is my metabolism too fast?
