There are two short words beginning with the letter "F" that can have nasty connotations. This discussion is rated 'G', but the other word is "fat". The media sells the idea that fat makes people fat, which contributes to a variety of health problems and, worst of all, being fat. Between the myths and insecurities for sale lies the arbitrary truth. An excess of body fat does contribute to many health problems, but the positive and necessary reasons why the body needs fat are often overlooked.

The boiled-down definition of metabolism is the sum total of heat (energy) the body produces. A person's metabolic rate "is indicated by the rate of heat production" (Brooks 39). That is, how much energy the body uses. Each individual will have a slightly different metabolic rate because the amount of energy the body needs depends upon different factors such as genetic make-up, hormonal balance, diet, weight, activity level, and percentage of lean tissue. But the processes by which the body creates, stores, and utilizes lipids are virtually identical in all bodies. (Brooks 39, Plowman 229)

No matter what the television says, fat does not necessarily create fat. How the body creates and stores fat is through "[the chemical synthesis of] carbohydrates and proteins which are taken into the body in excess of its needs" (Waugh 317) and once the synthesized fat energy, called triglycerides, are made they are stored in adipose cells underneath the skin. How fat found in the diet contributes to triglyceride production is though excess calories. At nine calories a gram, fat has more than twice the calories of carbohydrates or proteins. When fat from the diet is being digested, or the triglycerides are utilized, the body breaks down the fat into a chemical compound called fatty acids. Fatty acids are the chemical form of fat that allows the body to it as fuel for energy production. (Plowman 229, Thibodeau 803, Waugh 317).

A basic knowledge of the biological forms and functions of fat can help answer the pressing question of how to reduce fat to a healthy percentage and how the body utilizes the stored triglycerides during exercise. Taking for granted that the body has a normal hormone balance and set of genes, the long and the short of depleting excess triglyceride storage is taking in less energy -within reasonable limits- than the body metabolizes. But diet alone does not best reduce excess triglycerides. Another important method is exercise. This should be old news. But what is virtually unknown by the average person is that the type, intensity, and duration of the exercise makes the difference which energy source -fatty acids or sugars- the body will primarily use.

If the individual's intention is to make the body utilize fat as an energy source, then moderate or long duration, low-intensity, and aerobic exercises are best. "The shorter the duration, the more important carbohydrates are as a fuel, with fat being utilized more as the duration lengthens" (Plowman 238). Short duration exercises, such as strength training, are often high-intensity and have a similar effect upon fuel usage. Carbohydrates, or sugars, are the fuel that is used quickly, quickly replaced, and does not require oxygen to be utilized. Fat, however, needs oxygen to complete the chemical process from stored triglyceride to fatty acid. According to Plowman's Exercise Physiology, aerobic exercises that burn the most fat are low to moderate intensity, walking or swimming for example, and are in duration of 40 - 150 minutes.

A highly effective method that makes the body metabolize fat is a combination of weight training and aerobic exercise. Weight training increases the body's metabolism because there is an increase in lean tissue, which even at rest requires more energy to maintain. Also, because weight training is most often high-intensity, short-duration, and anaerobic exercise the body's glycogen (sugar) reserves are soon depleted. If aerobic, (ideally low-intensity and long endurance) exercise begins before the body can replenish the glycogen reserves, which usually takes about twenty to thirty minutes, then the body has little choice other than to begin drawing upon triglyceride reserves. (Plowman 238).

A common complaint about any exercise program and losing fat is reaching a plateau phase, or a significant period of time when no losses or gains are made. It is no accident that both goals can reach the plateau phase, which is more appropriately described as being in a rut. The plateau phase is discouraging and is often a part of the reason why people abandon their goals for change. Any type of change must necessarily include a change in environmental factors. Once the new changes have been adapted to, the changes become the norm, the proverbial rut. The only way to avoid the rut is through constant change. Knowing what factors to change can enable consistent gains in muscle mass and strength as well as a reduction in body fat. Periodization is a weight-training method that is based upon constant change and conforms to the needs and goals of the individual. While the theories and principles of Periodization can warrant an entire book, the core idea is that through the constant variation of factors, such as the amount of weight lifted, the number of repetitions, and order of exercises, consistent, therefore greater, gains are possible over time. Followed by a cardiovascular workout, plus tenacity and hard work, great gains (and losses) are possible without, ideally, hitting any plateaus.

Fat in excess is unhealthy, whether in diet or in the body, but fat itself is not evil incarnate. Fat is a necessary part of maintaining healthy energy levels and body functions. The process the body uses to store fat is the same for everyone; but the rate at which the body metabolizes fat is the difference. There may be some metabolic factors that cannot be easily changed, such as hormone balance or genetics, but diet and exercise are controllable. Putting less energy into the body will force it to compensate by drawing from fat stores. Any exercise done properly is beneficial, but to reap maximum rewards from the work that is exercise, it is necessary to understand the energy sources that different exercises demand. This, coupled with the constant change and stimulus that a Periodization program brings, will allow the individual to not only achieve fitness and weight loss goals, but also maintain them once they are reached. Beyond the goals, there are still more benefits of learning to keep fit and how the body functions: the power of understanding the body. A discovery of the surprising power and fragility of the body, learning to be comfortable with it, and casting aside myths and insecurities that can drown the self-image.

References:

Brooks, George A., et al. Exercise Physiology. (Mountain View, CA: Mayfield Publishing Company, 2000).

Plowman, Sharon A., and Denise L. Smith. Exercise Physiology. (Boston: Aylln and Bacon, 1997).

Thibodeau, Gary A., and Kevin T. Patton. Anatomy and Physiology. (St Louis: Mosby, 1999).

Waugh, Anne, and Allison Grant. Anatomy and Physiology in Health and Illness. (Edinburgh: Churchill Livingstone, 2001).