Hello,
Thanks for posting your query.
Weight gain is as difficult as losing it, if you are naturally thin. Gaining weight is a problem for many people. They complain that they can't put on any weight. Being lean and thin can be due to many causes and finding out the main cause will help in gaining the weight.
Genetics is the main factor responsible. If your parents or siblings are also underweight then may be it is in your genes.
The other causes that need to be ruled out are -
1. Depression.
2. Some hormonal disturbances like hyperthyroidism, Addison's disease - Some simple blood tests will rule this out.
3. Chronic illness - A long standing illness also causes lack of a healthy look.
4. Gastroesophageal reflux disorder (GERD) - I hope you do not have any pain abdomen, loose stools, burning sensation in upper abdomen, etc.
5. Viral gastroenteritis.
6. Stress and anxiety.
7. Malnutrition.
8. Intestinal worms.
Your hemoglobin levels of 11gm% are nearly normal.
All these causes need to be ruled out with the help of your physician after a thorough examination and some blood tests.

As far as your diet is concerned, the primary rule is to increase the calorie intake and do some form of exercise along with it.
It is not a good idea of increasing intake of junk foods and fatty foods to gain weight. You should be eating calorie dense yet nutritious food.
Your calorie intake should come from foods that are healthy for you.
The weight gaining diet should include high protein foods, high carbohydrate foods and healthy fats.

Following are some tips to follow to gain weight. You will take some time to gain the weight you need, but be patient.
1)Start your day with a healthy breakfast comprising a glass of milk and a banana or a banana milkshake.
2)Have frequent small meals every three hours in a day and divide them into six small meals comprising of proteins in one meal as pulses,cereals,beans,legumes, etc.
3)Have energy dense foods as dry fruits, nuts, seeds when you snack.
4)If you take non veg have fish,chicken with dal rice thrice in a week.
5)Avoid junk food intake as it has empty calories.
6)Make an exercise plan and do some form of muscle building exercises. It will be best if you do under guidance of a trainer so that he can analyze and observe for changes. Exercises like squats, chin-ups and bench press help in weight gain.
7)Avoid smoking, alcohol if you are using them regularly.
8)Drink lots of water.

You can consult a nutritionist who can guide you according to your cuisines and then keep tracking for changes. There is no substitute of eating a healthy diet for gaining weight.

I hope this answers your query.
In case you have additional questions or doubts, you can forward them to me, and I shall be glad to help you out.
Please accept my answer in case you do not have further queries.
Wishing you good health.
Regards.
Dr. Praveen Tayal.

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