Before the early 19th century, people relied on ice, snow and naturally cool areas in their houses to preserve foods that were for the most part produced locally. Today refrigeration technology in commercial food production and at home means that we have easy access to a broad array of foods from around the world. This change has a significant impact on the way we shop for food, and how we manage the food we purchase.
Frigidaire began mass producing electric refrigerators in 1918, and by the 1930s the name was synonymous with the appliance. Early to mid-20th century refrigerator technology involved passing coolants such as ammonia and freon through a circuit from a condenser to an evaporator circuit to draw warm air away from the refrigerator cabinet. Today refrigerator technology continues to evolve as environmental concerns about chlorofluorocarbon emissions have led to replacement of freon with safer alternatives such as HFC 134a.
Electricity made refrigerators a dependable appliance that people could rely on for food preservation and storage. Diets evolved when people could purchase and eat fresher foods year-round instead of relying on canned and cured foods in the winter. Local supermarket offerings diversified, making it possible for foods grown or produced locally and in distant countries to end up next to each other in the same home refrigerator.
Refrigerators make it easy to create menus and shop ahead for the ingredients we need for any diet, and the savings don't stop at the supermarket. Refrigerators preserve foods at 40 degrees Fahrenheit or lower by preventing the growth of pathogenic and spoilage bacteria for several days or weeks. When we can prepare foods ahead of time, or use leftovers for later meals, we save time and cooking energy costs that add up over the long-term.
While refrigerators make it possible for us to have a steady supply of healthy and nutritious foods, it can just as easily be used to store foods that are not good for you. You may also tend to overeat just because you have them within reach. The steady rise in obesity and obesity related illness in the late 20th and early 21st centuries emphasize the importance of learning to manage your daily calorie intake, and of limiting the unhealthy foods you bring into the house.