Global trends in child health have shown both progress and challenges in recent years. Improvements in healthcare access, vaccination programs, and nutrition have significantly reduced child mortality rates, with diseases like measles and polio being nearly eradicated in many regions. However, disparities persist, particularly in low-income countries, where malnutrition, limited healthcare access, and preventable diseases remain major concerns.

Genetic factors play a significant role in weight regulation by influencing metabolism, appetite, fat storage, and energy expenditure. Numerous genes are associated with obesity and body weight control, including those that affect the production of hormones like leptin and ghrelin, which regulate hunger and satiety.

Gut microbiota plays a crucial role in metabolism by influencing digestion, nutrient absorption, and energy balance. These microorganisms help break down complex carbohydrates, produce essential short-chain fatty acids, and regulate lipid metabolism. They also interact with the immune system and endocrine pathways, affecting insulin sensitivity and inflammation.

Metabolic disorders in childhood are a group of conditions that affect how the body processes nutrients and converts them into energy. These disorders are often caused by genetic defects that lead to enzyme deficiencies or dysfunctions in metabolic pathways. Common metabolic disorders in children include phenylketonuria (PKU), maple syrup urine disease (MSUD), galactosemia, and mitochondrial disorders.