Step 2. Define the baseline performance by step wise optimization
Next, the amount of the product of focus is varied in steps within the diet, optimizing at every step. At every step the diet is adjusted to meet the nutritional constraints. This means that at every step the amount of other food products is increased or decreased to make this happen. At every step the environmental impact of the diet is also calculated. The results of the stepwise optimization for milk for the impact on climate change is displayed in Figure 1.
The analysis shows that the relationship between nutritional value and the environmental indicator greenhouse gas effect for dairy products is virtually neutral in a Dutch diet. In other words; as a source of useful nutrients dairy products are just as environmentally efficient as the products used to replace them (Blonk Consultants, 2015). The results of the stepwise optimization for dairy for the impact on climate change are displayed in Figure 1. The gradient of the line in Figure 1 is the actual SNB-score. The lower the SNB-score the better the profile of the product of focus. The SNB-score can even be negative, which means that the environmental impact of the diet decreases when more of the product is consumed. This is demonstrated in Figure 2. The SNB-score of dairy is close to 0. Compared to the SNB-score of meat, this is very low. This means that dairy is much more future-proof than meat. The SNB-score of bread though, is below 0. This means that increasing the amount of bread in the diet can result in a lower environmental impact of the total diet, while keeping the diet healthy.