However, as for output indicators, trends in input indicators can be strongly influenced by factors not related to waste prevention measures. This includes changes in types of food being produced or consumed, demographic changes (i.e. changes in the age profile of the population) or simply increases or decreases in nutrient intake by people. Impact indicators take account of the fact that prevention of different types of food waste can give significantly different environmental benefits. This is because the production of 1 kg of meat or dairy products requires far more energy, material, fertiliser, land, water inputs and leads to more emissions to air, soil and water than the production of 1 kg of vegetables.