- Kwashiorkor is a form of severe malnutrition that primarily results from a deficiency of proteins despite adequate calorie intake.
- This condition is most commonly seen in children who are weaned off breast milk onto a diet that is high in carbohydrates but low in protein.

- The key pathological feature of Kwashiorkor is the inadequate intake of protein, which leads to a decrease in plasma proteins such as albumin.
- This causes a drop in the osmotic pressure of blood, resulting in edema and the characteristic swollen abdomen.
- Other symptoms include fatty liver, muscle wasting, dermatitis, and irritability.

- In contrast, a deficiency of carbohydrates, vitamins, or fats does not primarily lead to Kwashiorkor but may contribute to other forms of malnutrition or health issues.
- Therefore, the correct answer is Proteins.