Nutrients are substances gained from food and needed for the organism. Those are carbohydrates, proteins and fats. Usually, carbohydrates should occupy 50% to 60% of daily intake of calories, while the rest is divided among proteins and fats, and ratio of those two usually differs from person to person. Still, some general rule says that fats should be set at about 30%, while proteins should comprise 20%. As said, these numbers vary from region to region, depending on eating habits, type of cuisine etc. Also, each of these nutrients is divided into several subtypes (healthy and unhealthy variations). Of course, it would be much better to use only healthy food, but that is a problem for most of the people. Partially, this is because junk/fast food is relatively cheap and easily available. Other nutrients that are needed are vitamins and minerals and those can be found in vegetables and fruits, which is why they should be included in a daily menu, although it is not the case more than often.
Habits are also very important. This is what will define the structure of our body (muscle to fat ratio), and it might easily lead people into obesity. Habits are influenced by many factors so it is not easy defining what makes habits the way they are. On the other hand, getting rid of some eating habits is very difficult. Optimum eating is presented with eating healthy food, but just in the amount needed for a body's, but that is not easily achieved. Dieting and exercising are things that will help with maintaining the optimum health status of the body, but when people stop applying these methods, problem of eating habits still remains.
Healthy habits include eating 5 times a day. Breakfast should be the strongest meal (with the highest number of calories) and each next meal should be lighter and easier for the intestines to process. With high number of meals, the amount of food taken with each meal can be reduced and that is another thing that helps the digestion process to run smoothly. This will also reduce hunger. Another thing that people should be cautions about is the number of calories. For women, this value ranges from about 1200 to 1800, depending on the body needs, while for men, this value is set between 1500 and 2000 calories. Extreme physical occupations demand more calories.