Physical fitness is directly related to diet and exercise; these two go hand in hand. If anyone thinks that he can be physically fit just by following a strict diet regime, exactly the way the dietician prescribes, by strictly regulating his calories intake or balancing the various categories of nutrients he requires, one really cannot maintain a physically fit life.
Similarly, if one believes that he can just go on eating recklessly without caring for his calorie intake, believing that he will burn off everything in the gym, then that too is not the right attitude to have a physically fit life.
According to the researches constituted by various organizations, to achieve physical fitness you must balance both your diet and your exercise regime. Overdoing nothing is advisable. Nothing in excess is ever good or healthy. Many people tend to go overboard in either of the two.
For instance, many people believe that fats are nothing but calorie builders which pile up around the lower abdomen region and are the sole culprits for making one obese. So they totally stay away from fat. They believe that just by staying away from fat they can maintain their slim and trim figure and be physically fit. But they forget that fats provide the body essential heat and energy and the skin becomes dry and loses its sheen in total absence of it. Hence, if we totally avoid fat, we tend to be low in carbohydrates and energy too. Thus having moderate quantity of all essential nutrients is essential for physical fitness.
The correct option would be to have fat in moderate quantity and if you are obese and want to maintain your physical fitness then go to a gym and burn it out. When you burn out your extra calories, the body uses up and absorbs the nutritional aspects of the food that you had taken and expels the unused portion when you go for the high energy using, calorie burning work outs.
Eating a well balanced diet and exercising is the only route to physical fitness. There is no other way out. Together they prevent various diseases like heart diseases, diabetes and improve overall quality of life and even extend life. Although exercises are considered rather old fashioned and laughed at by the younger generation, nothing is better for your physical fitness than a sweaty, vigorous exercise. Even a moderate exercise does wonders, if you are unable to do vigorous exercises due to various health constraints.
However you must always consult a dietician before embarking on any major change in your diet. Those who are suffering from any ailment, especially diabetes or cardio vascular problems must essentially consult a dietician and a physician before embarking on any major exercise regime for physical fitness.
It is true that there is nothing as good as a combined diet routine and exercise regime but it should always be undertaken under medical supervision to avoid any complications that may arise. Physical fitness is important no doubt. But you definitely have to keep in mind your limitations and health conditions before setting upon a strict physical fitness routine.