How to solve the problem of a child being too thin

Patient's question:

11 months and still very thin, only 14 jin. Always been thin, what should I eat to gain weight? (Usually has a big appetite and good spirits, and eats seafood, eggs, and meat every day, but only 14 jin, not sure if the nutrients aren't being absorbed. So desperate

Doctor's answer:

Based on the situation you described, it is likely that the baby has a normal constitution. However, it is best to have the baby undergo a thorough examination at the hospital to rule out the possibility of calcium and zinc deficiencies.
Regarding the baby's complementary foods, it is recommended to start introducing vegetable juice and fruit juice gradually from the third month. From the fourth month, you can begin introducing rice porridge, egg custard, thin rice noodles, and other similar foods.
In general, follow the principle of gradual progression: start with small amounts, then increase gradually; start with thin textures, then move to thicker ones; introduce one type at a time, then gradually add more varieties; and progress from simple to complex.
If the baby experiences nausea or vomiting, temporarily pause the introduction of new foods. Once the condition improves, resume the gradual reintroduction of foods and continue to progress as before until a full recovery is achieved.