The review paper gives in details the current clinical guidelines for evaluation of the impact of nutrition on the correction of increased body mass index (BMI) and obesity, an overview of the efficacy of specific commercial diets, target criteria for weight loss, and monitoring the status of a patient who participates in a weight loss program. The current clinical guidelines suggest that today there is no optimal diet in terms of its impact on the correction of overweight and further maintenance of the weight loss achieved. There is a need for both the improvement of the professional capacity of healthcare workers in advising patients about nutrition and the population’s awareness about the principles of a healthy diet. The complex nature of the problem requires that a medical community should interact closely with politicians to make a legislative decision on a number of issues relating to healthy eating.