Human Nutrition - Balanced diet

A balanced diet provides all essential nutrients in the correct proportions: carbohydrates, fats, proteins, vitamins, minerals, water, and fiber.

Carbohydrates (e.g., glucose $C_6H_{12}O_6$) provide the primary energy source for cellular respiration.

Proteins are essential for growth and tissue repair; they are polymers of amino acids containing nitrogen, carbon, hydrogen, and oxygen.

Lipids (fats and oils) serve as long-term energy stores, provide thermal insulation, and are components of cell membranes.

Vitamin C ($C_6H_8O_6$) is necessary for maintaining healthy skin and gums; deficiency leads to Scurvy.

Vitamin D and Calcium ($Ca^{2+}$) are required for strong bones and teeth; deficiency can cause Rickets in children.

Iron ($Fe^{2+}$) is a vital component of hemoglobin in red blood cells; deficiency leads to Anemia, reducing oxygen transport.

Dietary fiber (cellulose) adds bulk to food, providing the muscles of the digestive system something to push against, thereby preventing constipation via peristalsis.

Energy requirements vary based on age, sex, activity levels, and biological states such as pregnancy or lactation.

Malnutrition includes both undernutrition (e.g., Marasmus and Kwashiorkor) and overnutrition (e.g., Obesity, leading to Type 2 diabetes and coronary heart disease).