BURN THE FAT, SAVE THE CARBOS
BY CAROLINE SMITH, M.S.
Have you been working out regularly, noticing you`re tired, sore, and actually gaining weight? If so, you may be fighting your body`s natural balance of exercise and nutrition. It is important to address how the body burns fat so you can customize your exercise program to reach your own goals.
The big picture (Figure 1) looks at the balance of calories in and calories out. Since the calories in are from what we eat, when we eat, and how we eat, this is influenced by what we are or are not doing to meet our calorie needs. The calories out are through exercise and metabolism. Metabolism is how our body uses the food we eat for fuel. Our goal is to reach a healthy weight in which the calories in match the calories out. To get to this point, we need to look at what it takes to be balanced and then alter that to achieve weight-management goals.
As a firefighter, your calorie needs will be quite high on a day full of calls, especially if some fires are included. The average firefighter burns 20 calories/minute on the frontline of a fire and about 16 calories/minute as a support person. A calorie is the amount of energy it takes to raise one gram of water one degree Celsius. This is a function of heat. Anytime you produce heat in the body or are exposed to heat, you will burn calories.
The two most popular ways to burn calories are through exercise and eating. Since all food is fuel, there is no such thing as good food and bad food; there are just better choices. When you eat a mixed diet (protein, fat, and carbohydrates), your body breaks down the food into smaller pieces and eventually provides the body with glucose (blood sugar).
The glucose travels in the blood to the muscles and liver and is stored as glycogen (see Figure 2). The storage area is drawn as a cup because there is only so much the body can hold at one time. Once the cup is full, excess calories are stored as fat. It does not matter if you eat proteins, fat, or carbohydrates; if you consume more calories than you expend, the body stores them as fat.
Once fat has accumulated in cells and enlarged the cell size, you want to remove it. The only way to remove fat is by exercise. If you exercise at a low intensity (60 to 70 percent of your target heart rate–see Fueling the Firefighter, December 1995, for formula) for a long duration, you will activate the fat-burning system. If you jump into exercise at a high intensity, you will use glycogen as a primary fuel. Glycogen can be stored for about 45 minutes. Once it is gone, it must be replenished through eating.
Let`s cover some basic physiology about how the fat burning system is activated. Muscle has glycogen in it for fuel; the fat is outside the muscle. Exercise causes muscles to generate heat and burn calories. During low-intensity (aerobic) exercise, oxygen is readily available and the body will oxidize or burn fat. If oxygen is limited–during anaerobic activities, for example–the body uses glycogen.
An enzyme in the muscle, lipo protein lipase (LPL) is the Pacman® of fat. When activated by hunger, the fat can supply fuel to the muscle as long as oxygen is available. The enzyme breaks the fat cell apart into smaller pieces, and the body then flushes the fat by-products from the muscle. Waste products are eliminated through urine and sweat, which are water-based. Therefore, water must be available from some source to generate a cleansing process.
Water is obtained from blood that is continuously flowing through the muscle. The blood is comprised of mostly water, some vitamins and minerals from the food we eat, and oxygen from the air we breathe. The volume of blood is dependent on the amount of water in the body. If enough water is not present in the body, the blood volume will be low, and less flushing will occur. This principle is reflected in Figure 3.
To maintain a good blood flow in the body at all times, drink eight to 10 eight-ounce glasses of water a day. Add an additional two to four ounces for every 15 minutes of exercise–and possibly even more in a very hot and/or humid climate. Train your body to take in water during exercise to avoid dehydration, side stitches, and muscle soreness.
This intake does not include other liquids. If you drink caffeinated products, you are actually losing more water than you are holding onto due to the diuretic effect of the caffeine. If you drink soda or juices from concentrates, the body has to dilute the sugar to carry it across the membrane for use. Additional water is needed to do this, more than the base amount. A cup of coffee requires one to two extra glasses, and soda requires four to five extra glasses of water for digestion.
When considering drinks to use during the rehabilitation cycles of a fire, look for those that have glucose polymers and fructose. Try to avoid products with sucrose, dextrose, corn syrup, or sugar on the label. One product, Take Up®, developed by Joseph Bonnano, a firefighter in the City of New York (NY) Fire Department, has exactly what you need. There are others on the market. the key is to find one you like because if you do not like the flavor, you will not use it, and thus it will not work.
Now, you can see how important it is to drink lots of water to properly cool the body and facilitate a good flushing of waste products. While it is important to exercise, you do not need to overexert yourself if your ultimate goal is to burn body fat. The key is consistency, at least four times per week for 30 to 45 minutes in the beginning. Once you have initiated the fat-burning principle in your body, you can maintain your conditioning level with three 30- to 45-minute sessions per week. n
CAROLINE SMITH, M.S., is president of SportSense Co., a Dallas-based consulting firm that works with individuals and groups on exercise and nutrition. She has a master of science degree in exercise physiology and bachelor`s degrees in psychology and nutrition. Smith also is wellness coordinator for the City of Richardson, Texas, where she created and implemented a physical fitness assessment and exercise prescription program for firefighters.