The increase in childhood obesity is a multifactorial phenomenon influenced by dietary patterns, commercial factors, and social determinants; it has long-term consequences for both individual health and society as a whole. Despite recommendations for maintaining good health throughout life and promoting the Mediterranean Diet, due to the increased availability of ultra-processed and more appealing foods, children and adolescents are shifting towards a Western diet. One in four children consumes sugary and carbonated drinks every day, which contributes to a high intake of fructose in the diet, while fruits and vegetables are consumed less, and legumes are included in the diet of only 38% of children less than once a week. Fructose is a monosaccharide naturally found in fruits, vegetables, and honey; due to its high sweetness and taste-enhancing properties, fructose is widely used in the food industry. High-fructose corn syrup, in particular, is one of the most widely used ingredients in the production of soft drinks, jams, breakfast cereals, and bakery products. Non-alcoholic fatty liver disease (NAFLD), now also called metabolic dysfunction-associated fatty liver disease (MAFLD), is considered the hepatic manifestation of metabolic syndrome and currently represents the most common chronic liver disease in pediatric age in Western countries. Recent studies suggest that fructose consumption is implicated in the development of NAFLD both directly by providing metabolites that can be used for triglyceride and free fatty acid synthesis, and indirectly through increased uric acid production. High-fructose foods also appear to be a risk factor for bone loss. Numerous studies conducted over the past 25 years, during which fructose consumption has exponentially increased, have shown that this sweetener tends to increase the incidence of fractures and osteoarthritis and decrease bone mineral density (BMD) and new bone tissue deposition. The objective of this study is to understand the effect of fructose on the molecular events that contribute to the evolution of the pediatric age, and its effective relationship with the onset of liver and osteoarticular complications in this population. Understanding the mechanisms of fructose regulation and its effects on the body could be an important target to address the clinical and social problems arising from its spread in children.