It is important to stay healthy and to have good eating habits and to exercise to keep your body fit. Being overweight is a big problem of many of the people all over the world. People who are overweight are usually at the risk of very serious health problems.
When choosing your diet, you will want to must count calories, as they measure how much energy is in the food that you eat. The energy is stored in the fat of the body.  The average woman will need to eat at least 1800 calories in a day. However if a person eats more than the average calories in a day and does not exercise enough to burn it off they will gain weight.
Other factors on should consider when creating a diet is age, metabolism, genes and of course pregnancy. It is normal for women to gain weight when they get older, lose mobility or inherited the genes of someone who has the tendency to be heavy. Weight gains are also normal during menopause. Some women do not lose all of the weight, when they have a child.  

A healthy diet should be nutritious and should have 100% of all the daily nutrients you need. You can get a list of what is needing by obtaining the dietary reference intake (DRI) or the recommended daily allowance (RDA). It is also important to get the right amount of exercise to burn off the calories. Also you will want to get a balanced diet, to do that you must eat from the basic food groups, the US department of Agriculture has designed a website to tell you how many servings you will need to eat on a daily basis in order to stay healthy. The food groups are grains, fruit, oils, milk, vegetables and meat (and beans).