In a fact sheet we show how dairy products perform in terms of their nutritional value and environmental impact. We then compare this with meat.
We look at the full range of nutrients supplied by dairy and meat products, as far as these are covered by Dutch standards.
Food production and consumption accounts for 20–30%of global emissions of greenhouse gases. About 14.5%of global emissions can be attributed to animal products.Another important environmental factor in food production is land use, as fertile agricultural land is scarce. Of the 5,000 million hectares of land in agricultural use – about 38% of the global land surface – almost 70% is grassland or pasture for grazing livestock.
Changing dietary patterns can make a considerable contribution to reducing greenhouse gas emissions and agricultural land use. Of course, the new diets must also provide sufficient energy and nutrients. This means that the key to devising healthy and more sustainable diets is getting the right balance between nutritional value and environmental impact. This can be determined quickly and accurately using Optimeal®, an optimisation program developed by Blonk Consultants and the Netherlands Nutrition Centre.
An average Dutch diet was entered into Optimeal®. Then, step by step, dairy products were added to or removed from this diet to produce diets with a range of from 0% to 300% of the current intake of dairy products. As the amount of dairy products was reduced, other foods were added to provide the missing nutrients. Optimeal®chooses a package of substitutes that requires the least possible change in diet while meeting all the standards for energy and macro- and micronutrients, which are boundary conditions in the model. Conversely, as dairy products are added to the diet,they replace other products.
The same procedure was followed for meat in the diet.The starting point was an average Dutch diet based on the Dutch Food Consumption Survey (VCP) 2007–2010 for men and women between 31 and 50.
Optimeal® uses the quadratic programming optimisation technique to ensure that the altered diets remain as close to the current diet as possible. During the process the program keeps track of trends in two environmental indicators: greenhouse gas emissions and land use.
The model contains information on the nutritional value and environmental impact of 208 products from the Dutch Food Composition Database (NEVO) selected on the basis of their weight fraction in the Dutch diet, with the addition of some pulses, meat substitutes and soy drinks. The environmental impacts were determined by carrying out a life cycle analysis (LCA) to calculate the greenhouse gas emissions and area of agricultural land used during the whole life cycle (cradle to grave) of each product.
Results and Discussion
The current consumption of milk products and cheese formed the benchmark and these values were set at 100%. Figure 1 shows the changes in the amounts of other product groups in the diet as the amounts of milk products and cheese are varied from 0% to 300% of those in the current diet. In all cases the diets consist of an optimised package of foods that meet all nutritional standards and remain as close as possible to the composition
of the current diet.
Figure1: Changes in composition of the diet as the amounts of cheese and milk products are varied. Drinks are not included