Fitness is extremely critical in this day and age where many of us have jobs that keep us from moving for large portions of the day. The human body was designed in such a way to be constantly on the move and our energy processing capabilities are geared towards this. Our bodies are designed to have fuel consistently throughout the day to have better levels of energy. Do you eat frequently enough in small portions?
As such our sedentary lifestyles are very harmful to us and put a significant toll on our organs and bodies in general. As such it is important to go through a fitness regimen to make up for the fact that during our normal day we do not burn that many calories. Many different programs for rapid weight loss are promoted but this should not be your ultimate goal if you are looking for sustainable health.
Sustainable health is based on the simple principle that the calories you take in should be the same as or lower than the calories you burn otherwise you will gain weight and this will be unhealthy fat weight. This means that there is no shortcut to fitness.
The key to sustainable long-term health is to eat a very healthy diet low in fat and rich in vitamins and protein and to work out intensively. These workouts should be aimed at building muscle which is the body's best fat burner and burning fat via cardio. Short workouts are all your need and aim for 50 minutes of activity each day.