CHAPTER 16

Build Better Metabolism

Even as you sleep or sit staring into space, your body is burning energy. The rate at which you expend energy while resting is called your basal metabolic rate. The body needs additional energy when you're exercising. The harder you work, the more energy you burn.

PART 1 Exercise - The Basics

All the fuel we need is in our food. When we consume a delicious meal packed with protein, fat, and carbohydrates, our body breaks down the nutrients, then repackages them so that we can use them for energy—either immediately or later on.

Nutrients absorbed from food in your digestive system have multiple destinations. Fats are broken down into fatty acids and may be reconstructed into triglycerides to be stored in your fat cells. Proteins are broken down into their component amino acids that are used to build various cells throughout the body. Glucose, also called blood sugar, is taken up and used directly from your bloodstream. Insulin signals cells to gather up blood glucose and use it for immediate energy. Other sugars are stored in your liver, kidneys and muscle cells to be used when your ready supply of blood glucose is depleted.

PART 2 The Exercise Effect

Working out can be compared to driving a car. The farther and faster you go, the more fuel you use. For a short, fast trip, you have to make sure you have enough in the tank to get you there. For a longer drive, you should plan to refuel a few times along the way.

Metabolism is the process of burning fuel to do our work. During exercise, glucose uptake by the working muscles can increase 7 to 20 times over the resting level, depending on the activity's intensity. This is when our metabolic processes are most stringently tested. With repeated bouts of exercise, our body gets more efficient at summoning fuel and using it. READ MORE

Endurance athletes have to have a long-distance energy plan. Marathon runners, distance bikers and others burn so much fuel during their events, they would empty the tank before getting halfway to the finish line if they didn't refuel. That's why you see endurance athletes downing carbohydrates for instant energy during their events. LESS

PART 3 Fat-Burning Magic?

A favorite claim of commercial exercise programs is that they will help you keep burning fat for hours or days after you work out. The same is true of breathless dietary supplement claims. The truth is, while you may have revved-up metabolism for a short time after working out, the key fat-burning happens while you are exercising no matter what you do or eat. But the more you exercise, the better your body gets at burning fuel efficiently. READ MORE

What researchers have found is that after a very intense workout, your metabolism may stay elevated even though your body is at rest. The length of time for which this happens depends upon many factors: your basal metabolic rate, the intensity of your exercise session, your gender, your age and your current fitness level. The larger point is, no matter how long your body burns fuel at a higher rate after a workout, the greatest expenditure of energy and burning of fuel is during the exercise.

It is true that building muscle mass helps increase your basal metabolic rate, but just a little bit. A pound of muscle at rest uses about six calories of energy per day while a pound of fat uses two calories. So while every pound of muscle is burning up more fuel than each pound of fat, at the end of the day those numbers are negligible. If you focus on achieving fitness by challenging yourself with aerobic and anaerobic workouts, the lean-to-fat ratio and weight loss effects will take care of themselves. LESS