Understanding your body requirements is an invaluable tool for developing fitness. your daily body requirements include vitamins, minerals, protein and fiber. Vitamins and minerals are the elements that are necessary for chemical reactions that unlock energy or enable growth. Although your body can store some vitamins, a regular daily intake is important because some of the most vital vitamins, B and C, are water-soluble, so are quickly flushed out of the system.
It's important to ensure your daily food intake includes all the nutrients your body needs.

Eat more fruit and vegetables

Eat more starchy foods such as rice, bread, potatoes and pasta (preferably whole grain varieties)

Eat less fat, salt and sugar

Eat some protein-rich foods such as meat, fish, eggs and pulses.

Eat a variety of foods to ensure your body gets all the nutrients it needs

Water
Drink 6 to 8 glasses of fluid a day to prevent dehydration. In hotter climates, drink more.
Fruit and vegetables
One third of the food you eat every day should be fruit and vegetables - aim for a minimum of five a day, and eat a variety.
Salt
Too much salt raises your blood pressure, so cut down as much as possible.
Fat
Some fat is vital to the body, but eating too much causes weight gain, so choose low-fat alternatives where possible.
The average woman needs around 2000 calories per day to fulfill her body requirements. This calorie requirement rises to 2500 for average men. However, these figures are based on averages and may be completely different for many individuals. If the same person becomes less active then calorie requirements will be lower. For this reason calorie requirements are highly individual and different for the different type of body characteristics such as height, gender, age and activity levels.
Energy is used up in physical work as well as in exercising for pleasure. People who do physically demanding work need to make sure they get enough food to meet their energy needs. It's also important that they find time to rest and relax at the end of the day to let their bodies recover.
Children, and adults with less demanding physical work, have lower calorie requirements than People who do physically demanding work. They should exercise or play a sport to stay fit and maintain a proper weight. Brisk walking, swimming, jogging, cycling or playing ball games are all ideal.
Lack of exercise in the elderly can reinforce age related limitations and handicaps that further reduce physical activity. The elderly should therefore try to take diet according to their calorie requirements, and keep up a comfortable level of physical activity. Gentle exercise such as walking or swimming is ideal. Irregular, strenuous exercise should be avoided.
Those who have been inactive for long periods, especially if this is as a result of illness, should have a health check before starting to exercise or resuming heavy physical work. Activity levels should be built up gradually, taking care not to do too much too soon and fulfilling calorie requirements according to activity levels.
Moderation is the golden rule. Eating in moderation combined with moderate exercise is the best approach for everyone.
Regular exercise and a balanced diet that best meet their body requirements, helps people stay fit and healthy.