The definition of fitness is the amount of work a person can do in a given period of time. There are three basic parts of the fitness pie:
1. The Diet
2. The Aerobic Exercise
3. Strength Training
The goal in applying each part is to raise metabolism (the rate your body burns calories at rest). This heightened metabolism is what makes people feel better immediately when they start exercising.
Most people need to reduce their percentage of body fat in order to achieve that slim waist or firm hips and thighs. Diet is the most important factor in fitness, because even if you exercise religiously, you will not lose fat unless you take in fewer calories than you expend.
One of the first steps in deciding what to eat is to determine how much food (calorie-wise) should be consumed to cause fat loss. The simplest way to calculate your needed daily caloric intake is to multiply your present weight (in pounds) by 15 calories (12 calories to meet the minimum basic needs, plus 3 calories for the energy needed for a physically active lifestyle). For example a 150 lb individual would need 2,250 calories daily to sustain current body weight. The next step is to reduce the daily total by 250 calories - the amount necessary to achieve a one pound weight loss per week when combined with an exercise program to burn an additional 250 calories a day. Combined, these two steps yield a net negative caloric balance of 500 calories daily. Because one pound of body fat has 3,500 calories, you can lose 1 pound a week (7 X 500 = 3,500) with this plan - a moderate rate of loss that is more likely to be sustained than a "quick fix" approach.
Aerobic Activity burns body fat as a fuel, and elevates metabolism for several hours after the activity is completed. The definition of aerobic exercise is any activity that raises the heart rate to at least 60 % of it's maximum for a minimum of 20 minutes. To determine your target heart rate, subtract your age from 220 and multiply by 60% for your minimum target heart rate and 85 % for your maximum target heart rate. Your heart rate should stay between these two numbers for at least 20 minutes. A simple way to check heart rate is to find the pulse on your neck, count the number of beats in 6 seconds, and add a Zero "0" to get the number of beats per minute. Aerobic activity is recommended at least 3 times per week.
Keeps metabolism high by at least maintaining the muscle you already have, which burns calories, even at rest. Strength training is recommended at least three times per week.