If fad dieting fails to decrease pounds and increase metabolism, then it may be time to try a different approach!
Understanding your personal caloric needs and the effect of physical activity on those needs is important, it can also be unnecessarily confusing. Basically, the number of calories you need to eat each day is derived from many factors including your age, weight, height, gender, lifestyle, and overall health and fitness. It is common sense that a physically active 6 feet tall, 20 year-old man or woman needs more calories than a less active, 5-foot, 75 year-old man or woman ... but how does a person find out how many calories they need based on their lifestyle and metabolism? It's really not that hard.
A good cardio workout is a cornerstone of an effective weight loss program, but if you're try to build muscles -- don't overdo it!