No matter how careful you are, cooking of any kind destroys some nutrients. The total amount lost will depend on the freshness of the food to begin with, how long you cook it and at what temperature, and how much surface area is exposed to water and air. Certain nutrients are more likely to be destroyed by heat than others, such as vitamin C are and B vitamins such as thiamin and riboflavin are. Others, including most vitamins and minerals, are likely to leach into cooking water.

Here are few guidelines to help you prepare foods especially vegetables and fruits so they stay as nutritious as possible:

• Cook foods for the shortest time possible. Microwaving, steaming, and stir frying are the quickest methods. Covering a pot or pan will help cut cooking time.

• Cook vegetables whole and unpeeled whenever possible or eat them raw. Avoid buying precut produce.

• Never soak fruits and vegetables.

• If you are boiling vegetables, use as little water as you can. Do not place them in the water until it is at a full boil. This will cut down on cooking time.
• If you use the water from boiling or steaming to make soups and gravies, you will consume any nutrients that leached away.

• Do not leave cooked food standing at room temperature.

• Cook foods as close to serving time as possible.

• To get the most from fresh produce, shop frequently and buy only as much as you will need in a few days.

• If the only vegetables and fruits available look wilted or pallid, or if they tend to sit in your refrigerator for a week, you will be better off frozen.

• Frozen fruits and vegetables may retain more vitamin C than fresh produce that has been mishandled in transport or storage or that has sat in the grocery store for days.