Which of the following lipids-related effects contributes to the feeling of fullness?

The feeling of fullness, or satiety, often relates to the energy density of lipids. Lipids, or fats, are high in energy, providing more than double the calories per gram compared to carbohydrates and proteins. Due to this high energy density, consuming lipid-rich foods can lead to a quicker sense of fullness, as they can provide a significant amount of energy with relatively small volumes of food. This characteristic can help regulate appetite and food intake, making individuals feel satisfied sooner and potentially reduce overall calorie consumption.

The other effects mentioned do not directly contribute to the feeling of fullness in the same manner. Increased insulin levels can relate to how the body processes energy but is more associated with blood sugar regulation than immediate satiety. High fiber content is often linked to fullness, but it’s not a lipid-related effect. Low water absorption can influence food textures and digestion but doesn't primarily trigger fullness related to lipids. Thus, the energy density of lipids is the main factor that contributes to the sensation of satiety.