Portion size refers to the amount of food served or consumed in one sitting. It can vary widely depending on the type of meal, cultural practices, and individual preferences. Understanding portion sizes is important for maintaining a balanced diet and managing calorie intake. In nutrition, portion sizes can influence eating habits and overall health. For example, larger portions may lead to overeating, while smaller portions can help control weight. Tools like measuring cups and food scales can assist individuals in determining appropriate portion sizes for different foods.