The phrase processed food is a nutritional hot potato, generally viewed in an even more negative context than prepackaged food. But, processed foods are just foods that have been altered from their natural state and can include freezing, canning, cooking, dehydrating, or even pasteurizing milk for safety.
You probably wouldn’t consider the processing of a grape into a raisin as some horrible insult to a formerly healthy food. To judge whether a food has been processed for your benefit or to your detriment, you have to consider what processing does to the nutritional value of the food.
Whole grains, such as wheat and rice, provide good examples of how processing can reduce nutritional value. To make white flour, for example, both the germ and the bran of the original whole grain wheat are discarded. The same holds true for white rice. It wouldn’t be accurate to say that white bread and white rice are unhealthy, but neither offers the health benefits of the natural whole grain versions.
The hydrogenation of liquid fats to create a solid trans fat, however, is processing with clear negative effects on health. Trans fats raise bad LDL cholesterol levels, and lower good HDL cholesterol levels, increasing the risk for heart disease.
Consuming red meat processed into hot dogs and lunch meats appears to increase the risk for diabetes significantly beyond the risk of red meat alone, according to data from long-term observational health studies. Processed meat is mechanically manipulated, but also usually includes the addition of preservatives like sodium nitrite. These two examples illustrate processing that has a distinctly negative effect on your health.
Notice that hydrogenation and the addition of nitrites refer back to additives and preservatives. Much processing of food is to improve the quality, shelf life, flavor, appearance, safety, or nutritional value of the food products. Many cereals and breads are enriched with added vitamins, for instance, and the processing of milk by pasteurization reduces the risk for disease.
Once again, your focus should be on the nutritional benefits of food to blood glucose control and the risk for heart disease instead of on the popular idea that processed equals bad — in some cases that’s true, but in some cases it’s just the opposite. Knowing how the foods you choose can minimize the impact of diabetes on your long-term health and adopting those healthy eating habits is what’s really important.