Some food production will never make it to markets, but will be lost in the field or in distribution systems to pests, spoilage, etc. For crops, an initial estimate of the loss in the first year, LOSSI, is given as a function of GDP per capita using a table function that captures the tendency of loss to decrease with higher income levels (see figure below). This is reset to 0 in the pre-processor if the estimate of cereal production in the first year is zero. If the loss seems too high, specifically if it is greater than or equal to 0.9 - cereal exports/cereal production, then the loss for crops is recomputed as the maximum of 0.05 and 0.9 – cereal exports/cereal production. The estimate of loss in the first year for meat is assumed to be one-half of the initial estimate for crops; no losses are assumed for fish.
In future years, for crops and meat, the loss is calculated as the loss in the first year multiplied by the ratio of the loss estimated from the table function above using current GDP per capita to GDP per capita in the first year; therefore, as GDP per capita increases relative to the first year, loss decreases. A common loss multiplier ( lossm ) is also available, allowing users to adjust crop and meat losses. Finally, losses are bound between 0 and 0.8. At present, fish loss remains constant at 0 for all years.