What causes the greatest loss of nutrients during food preparation?

The greatest loss of nutrients during food preparation often occurs when foods containing certain nutrients, like vitamin C, are soaked or cooked in water. Water-soluble vitamins (such as vitamin C and many B vitamins) can leach out into the cooking water, especially if the food is cooked for a long time or at high temperatures. This means that the longer the cooking process and the more liquid used, the greater the potential loss of these vital nutrients. This is particularly significant when the cooking water is discarded, as the nutrients dissolved in the water will not contribute to the nutrition of the meal.

While washing fresh vegetables is an important step for food safety, it typically does not result in a substantial loss of nutrients compared to cooking techniques. Dehydrating raw fruits and vegetables can preserve many nutrients, although some vitamins may be diminished through this process; however, the primary issue at hand relates to cooking methods. Cooking whole foods versus cutting them into smaller pieces can affect cooking time and potentially nutrient retention, yet this generally does not lead to nutrient loss as significant as that seen with nutrient leaching into water during cooking.