For most of the world's population, eating is no longer what it was just a few decades ago. The diversification and globalisation of the food supply, the industrialisation of food, and the abundance of information have simplified this everyday activity, but they have also made it more complex. Never before has it been so easy to eat well and to eat poorly. The proof is that obesity and overweight are no longer a problem exclusive to the richest, while nutritional deficiencies do not affect only the most impoverished. The new thing about our time is that both problems, over-nutrition and under-nutrition, coexist not only in countries and cities, but also within the same family and even throughout a person's lifetime. Growing concern for health has fuelled interest in the relationship between diet and disease prevention. But despite the remarkable scientific advances, there are still many unanswered questions, and many evidence-based messages do not reach the population and are lost in a sea of misinformation and half-truths. In this monograph, apart from presenting a brief social history of food, we will delve into the advances in nutritional epidemiology, we will separate facts and fiction regarding current food, we will review what reliable dietary recommendations are and how they are identified, we will explain the evolution of dietary guidelines with an example, we will tackle the problem of ultra-processed food from the point of view of addiction and we will analyse miracle diets and how to detect them.