One of the most challenging components of a nutrition plan is determining the appropriate caloric intake that compliments your fitness goal. As a society, we consume 260 more calories a day than we did 10 years ago. The over consumption that Americans engage in is causing the obesity epidemic that is not only effecting the health of adults, but children as well.
Because it gets drilled into our heads that we're eating too much, when an individual starts to change their nutritional habits, it's a knee jerk reaction to drastically cut calories. Now instead of consuming too much, they are consuming very little. This causes cravings that are difficult to control and an appetite that goes haywire. Eventually, this decrease causes metabolism to slow down and in turn creates a vicious cycle of yo-yo dieting.
First, let's take a look at the science of the energy equation, the First Law of Thermodynamics. This basically states that energy cannot be created or destroyed, only transferred. It's also known as the Conservation of Energy. So what does this mean in the world of fitness? If you eat too much and move very little, calories (energy) are stored and weight increases. If you eat less and move more, calories (energy) are burned and weight loss occurs. It's basic math, simple addition and subtraction. However, our bodies are more complex than elementary mathematics. What happens if you eat little and workout often, but your weight doesn't change. Or worse, you gain weight. What is the science in that?
If this truly happens, there is either an under reporting of caloric consumption (caloric amnesia or nutrition denial) or the body is not getting the amount of energy it needs. It boils down to your Basal Metabolic Rate (aka: resting metabolic rate). Your BMR/RMR is approximately the amount of energy expended during rest or the amount of calories needed to sustain life. The release of energy in this state is sufficient only for the functioning of the vital organs, such as the heart, lungs, brain and the rest of the nervous system, liver, kidneys, sex organs, muscles and skin.
What happens in this drastic decrease is that the daily caloric total is often less than an individuals BMR/RMR. The body does not get what it needs, lean body mass (muscle) is lost and metabolism slows down, meaning your body burns less calories at rest than it did before. Optimum performance does not occur at this level.
The car analogy is perfect for this situation:
Your planning on driving across the country. The first thing you think about is filling up the gas tank, but you get too busy and forget. You start your trip but end up getting stranded on the side of the road because the car ran out of gas.
Your body is that car, but much more amazing. Your cross country trip is your fitness goal and the gas is your calorie consumption. When you consume too few calories, your amazing body will not leave you stranded on the side of the road. No, your body will find an alternative source of fuel. Muscle and organ tissue. Your body becomes catabolic (breaking itself down) to keep you alive and going. The loss of lean body mass increases body fat. The metabolic processes slow down attempting to conserve energy.
Taken to the extreme, this is weight loss through anorexia. However, the majority of individuals who drastically cut calories are not anorexic, nor intend to be. They are walking the fine line. They are consuming enough to live, but not enough to function (metabolically) efficiently. More often than not, it's a difficult lifestyle to maintain and the individual gives in to binges, continuing the yo-yo cycle.
For optimum health and performance, one needs to think "balance". Don't be afraid to eat. Just don't over do it. Balanced nutrition complimented with a balanced workout routine will ensure overall fitness success and it won't compromise your health or wellness.