Muscling Up Your Metabolism

Why do many people think that to lose body fat they must spend countless hours on the step machine, treadmill, or bicycle, while spending little or no time pumping iron? The latest news about fat loss may surprise you and allow you to stop running around in circles. It's time to update your workout program and redefine your fitness goals, using the best information-- based on scientific research-- about what makes you stronger, healthier, and more fit.

First, let's define some basic terms related to why strength training helps build muscle while reducing fat. The scientific term for weight is mass. The term body composition refers to dividing the body's mass into fat-free mass (FFM), fat mass (FM), and lean body mass (LBM).

FFM consists of the portion of muscle, bone, and organ weight that contains no fat. FM is total body fat, which includes essential fat and storage fat. As we discussed in chapter 1, the body requires essential fat to maintain normal physiological functions. It is found inside organs, bones, and nerves, and on women also in the breasts and around the reproductive organs. Some storage fat is necessary to protect both men's and women's internal organs from trauma and to provide the body with reserve fuel. The other type of storage fat is made up of unburned calories from Oreo cookies and Haagen-Dazs ice cream, and is not necessary for life (unless you've going through a relationship breakup!). When most of us say that we want to lose fat, it's that Oreo cookie storage fat that we want to lose.

A person's lean body mass (LBM) is the amount of FFM and some FM that is essential for life. When body composition measurements are taken, the results tell you your percentages of FM and LBM. When you decrease FM and increase LBM, your body composition improves favorably, and the body takes on a harder and more muscular appearance with less fat. Remember, though, that muscle is denser than fat, so when you gain muscle and lose fat you end up with a net zero equation. Therefore, increasing muscle won't likely increase your body circumference by much. However, most people who gain muscle and lose fat also increase their body's metabolism-- thus increasing the rate at which they burn calories.

People who are overweight often claim that their body has a slow metabolism and that that's why they can't lose weight. They are wrong. The real reason they are gaining weight is that they are not active enough. Fat is biologically inactive tissue. In other words, it doesn't do anything except sit on the couch with the remote control and keep us warm. Muscle, on the other hand, is constantly at work, even at rest. It generates and gives off heat and requires energy (calories) to do these things.

When we are awake, our bodies need energy to perform all sorts of activities just to keep us alive. The amount of energy that our bodies need for normal physiological functioning while we are awake is called our basal metabolic rate (BMR). The resting metabolic rate (RMR) includes the BMR plus the amount of energy we use when we are sleeping and waking up from sleep. Our total body metabolism actually refers to our total daily energy expenditure (TDEE) and is a combination of the RMR, our physical activity, and the thermic effect of food (TEF).

Your body actually burns calories from the food that you eat through the processes of chewing, digestion, and absorption. The body uses approximately 5 to 10 percent of the total calories of the food you ingest to process that food, and this calorie use is the TEF. On average our TDEE is divided up into approximately 60 to 75 percent for RMR, 10 percent for TEF, and 15 to 30 percent for physical activity (see table 3.1). Although a certain percentage of our TDEE is genetically programmed, we do have direct control over some areas. For example, we can increase our physical activity simply by training longer, harder, or more Resting metabolic rate (RMR) 60 to 75% days per week, and we can increase our RMR by adding more muscle to our bodies. Strength training is the best way to add more muscle to our bodies and increase our RMR.

Cardiovascular Endurance Exercise and Metabolism

Strength Training and Metabolism