Canning and freezing do not in and of themselves have much impact on macronutrient content. Tuna is the major exception to this. Since it is a physically large fish, it is customarily cooked before being packed in the can for final processing. During this initial cooking process, some lipid is lost. A more important loss of lipid occurs when the lighter coloured (low lipid) meat is selectively used for canning. This is done for reasons of consumer preference, since the high lipid dark meat has a deep brown-red colour, which is deemed unacceptable to consumers. The parts of the carcass used for producing smoked salmon have a lower inherent lipid level than the carcass as a whole, and so the product has a lower lipid content than whole salmon, in spite of having lost some water in the smoking process. Since salmon are only fairly lightly smoked, the loss of moisture is not great.