Explanation

Balanced diet contains: carbohydrates (energy), proteins (growth and repair), fats (energy, insulation, cell membranes), vitamins, minerals, water, and fiber.

Malnutrition includes deficiency and excess. Kwashiorkor: protein deficiency. Marasmus: overall calorie deficiency. Obesity: excess calories, increases disease risk.

Digestion breaks down food: mechanical (teeth, churning) and chemical (enzymes). Each macronutrient has specific enzymes and absorption sites in the digestive tract.