The diet which meets all the metabolic requirements of the body is called a balanced diet. It contains all the food components in optimum proportion and quantity. Overnutrition and undernutrition lead to ill health.
nutrional disoders: malnutrition and overnutrition
Nutritional disorders due to deficiency of dietary components
1. Anemia
    Deficiency nutrient: Fe
    Symptoms: Decrease in number of RBC and amount of Hb.
2. Megaloblastic anemia
    Deficiency nutrient: Folic acid (B9)
    Symptoms: Large, immature nucleated RBC in blood.
3. Pernicious anemia
     Deficiency nutrient: Cyanocobalamin
    Symptoms: Large, immature nucleated RBC without Hb
4. Night blindness
    Deficiency nutrient: Vitamin A
    Symptoms: Less rhodopsin in the rod cells leads to poor vision in dim light.
5. Xerophthalmia
    Deficiency nutrient: Vitamin A
    Symptoms: Keratinized ulcerated cornea leads to blindness especially in children.
6. Rickets (in children)
    Deficiency nutrient: Vitamin D
    Symptoms: Weak soft bones due to poor deposition of Ca and PO4 in the bones.
    Bending of long bones (bow leg), swelling on wrist, elbow etc.
7. Osteomalacia (in adults)
    Deficiency nutrient: Vitamin A
    Symptoms: Weak bones of vertebral column, deformed pelvis etc.
8. Beriberi
    Deficiency nutrient: Vitamin B1
    Symptoms: Numbness and weakness of limb muscles, paralysis, odema, cardiac failure etc.
9. Scuvy
    Deficiency nutrient: Vitamin C
    Symptoms: Fragile blood vessels, bleeding gums, loose teeth, delayed wound healing.
10. Marasmus
      Deficiency nutrient: Protein
      Symptoms: Emaciated body with thin limbs and prominent ribs, wrinkled skin, diarrhea etc.
11. Kwashiorkor
     Deficiency nutrient: Protein
     Symptoms: Wasting of muscles, protruded belly, oedema, diarrhea etc.
12. Pellagra
        Deficiency nutrient: Niacin (Nicotinamide)
        Symptoms: Thick pigmented skin, swollen lips etc.
Nutritional disorders due to Overnutrition
13. Hyperchlesterolmia
       Excess nutrient: Saturated fats like butter, ghee, vegetable oils, meat, egg etc.
       Symptoms: High cholesterol level which deposits on the walls of blood vessels causing their stiffening, rise in blood, pressure, cardiac disorders.
14. Obesity
       Excess nutrient: Food with high calories such as sugar, honey, ghee
       Symptoms: Accumulation of fat in tissues. High blood pressure, cardiac disorders etc.
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