Assessment of Current Weight Status
At 5'9" and 50 kg, you are considered underweight. Gaining weight is advisable for better health.

Nutritional Strategies
a. Increase calorie intake with balanced meals.
b. Focus on protein-rich foods, healthy fats, and complex carbohydrates.
c. Consider using supplements like Optimum Nutrition Serious Mass if needed.

Exercise Recommendations
Engage in strength training exercises to build muscle mass.

Monitoring Progress
Track your weight weekly and adjust your diet as necessary.

When to Seek Medical Advice
Consult a healthcare provider if you struggle to gain weight despite these efforts.