For over a century, public health institutions have provided dietary guidance to the public, evolving in response to the scientific understanding of the time. The earliest advice focused squarely on ensuring nutrient adequacy. The primary goal was to help people get enough essential vitamins and minerals to prevent deficiency diseases like scurvy, which results from a lack of vitamin C, or diseases caused by other specific nutrient deficiencies. This era of nutrition was defined by a simple, clear objective: to prevent the acute illnesses that arose from a lack of essential nutrients in the diet.