Prof. Dr. Semin Melahat Fenkçi, Head of the Department of Endocrinology at PAU Hospitals, made the following statements: “Let us begin with the question, ‘How did the sugar molecule found in DNA, the building block of cells, become toxic to humans?’ In fact, glucose (blood sugar) is a fundamental source of energy for the human body. The nutrients we consume undergo various chemical processes in the body and are converted into glucose, which is used in cells, particularly in the mitochondria, to produce the energy necessary for life. Excess energy is stored as glycogen and fat and reused when needed. In other words, the system is based on a delicate balance between energy needs and energy storage. The problem is not so much glucose itself as consuming more energy than needed, particularly added sugar, over a prolonged period. When excess energy becomes continuous, cells may gradually become less responsive to insulin. This is called insulin resistance. Thus, even though glucose is present in the blood, the mechanisms by which cells use and store glucose cannot function properly. As blood sugar levels rise, metabolic balance gradually deteriorates, and the process leading to type 2 diabetes may begin. Another important effect of high blood glucose is that it reacts with proteins to form advanced glycation end products (AGEs). These structures can disrupt the normal functioning of cells and tissues and, together with oxidative stress and chronic low-grade inflammation, may contribute to damage to blood vessels, kidneys, nerves, and other organs. A significant portion of excess fructose is metabolized in the liver. Excessive fructose consumption may increase the production of new fat in the liver, contributing to fatty liver, elevated triglyceride levels, and liver-derived insulin resistance. Over time, these metabolic disturbances may develop into a condition associated with type 2 diabetes, fatty liver disease, and cardiovascular diseases.”

Prof. Dr. Fenkçi: “Reduce Excess Sugar, Not Sugar Itself”

Prof. Dr. Semin Melahat Fenkçi stated that it is important to distinguish between the sugar naturally found in foods such as fruit and milk and sugar added to foods later, noting that the sugar in natural foods is consumed together with fiber, protein, vitamins, and minerals. Prof. Dr. Fenkçi, who said that the fiber in fruit, in particular, slows the absorption of sugar and provides a feeling of satiety, continued: “In contrast, added sugar found in sugary drinks, ready-made fruit juices, desserts, pastries, and many processed foods can be consumed in high amounts without being noticed. The low capacity of sugary drinks to create a feeling of satiety can also increase total energy intake, contributing to weight gain and obesity. The effects of excess sugar are not limited to metabolism. Sugar fermented by oral bacteria is one of the most important preventable causes of tooth decay. Long-term high sugar consumption can contribute to the development of a metabolic environment that poses a risk for many chronic diseases, including obesity, insulin resistance, fatty liver, and cardiovascular diseases. The World Health Organization recommends keeping the proportion of daily energy derived from added sugars below 10%, and, if possible, reducing it below 5%. In conclusion, glucose is indispensable for human life; the problem is not glucose itself, but the long-term consumption of excessive amounts of sugar, particularly added sugar. Our body initially tries to protect us by storing excess energy. However, when this energy surplus becomes chronic, processes such as insulin resistance, fat accumulation, oxidative stress, and inflammation come into play and may disrupt metabolic balance. Therefore, rather than declaring sugar itself an ‘enemy,’ it is necessary to consider its source, how much is consumed, and its place within the overall diet. For a healthy metabolic balance, reducing processed foods and foods containing added sugar should be considered together with a balanced diet, regular physical activity, and adequate sleep.”