What foods should an 18-year-old eat to gain weight?

This Premium Q&A, reviewed and published, features a real conversation between an iCliniq user and a physician.

Patient's Query

Hi doctor,

I am an 18-year-old boy, weighing 115 pounds and standing 5 feet 8 inches tall. I want to gain body weight.

Please advise.

Thank you.

Hi,

I appreciate that you have chosen icliniq.com for your medical needs.

I am here to give you the best care possible.

According to your height, your body mass index (BMI), calculated as weight in pounds divided by height in inches squared and multiplied by 703, is 17.45. Based on your height, the minimum normal weight should be approximately 121.5 pounds.

First, let me explain the normal BMI classifications according to the World Health Organization (WHO):

  1. Less than 16.0 BMI: Severe underweight.

  2. 16.0 – 16.9 BMI: Moderate underweight.

  3. 17.0 – 18.49 BMI: Mild underweight.

  4. 18.5 – 24.9 BMI: Normal weight range.

  5. 25.0 and above: Overweight.

This classification is internationally recognized. Since your BMI is 17.45, you fall in the mild underweight category. You are only about 6.6 pounds below the minimum normal weight range (based on a target of 121.5 pounds). So, there is no major need to worry.

However, one thing to consider is:

  1. Is your weight continuously decreasing? If yes, this may be a sign of an underlying chronic illness.

  2. How is your appetite and food intake?

To rule out any medical issues, I recommend a few basic health investigations:

  1. Complete blood count (CBC) and erythrocyte sedimentation rate (ESR).

  2. Complete urine examination.

  3. Liver function tests.

  4. Thyroid profile including T3 (triiodothyronine), T4 (thyroxine), and TSH (thyroid-stimulating hormone).

If you are non-vegetarian, consider including eggs and poultry in your meals. Milk and curd are also beneficial for healthy weight gain.

Since your weight is not significantly below the normal cutoff, you do not need a heavy diet. Instead, focus on a balanced and nutritious diet. Consuming a very high-calorie diet may lead to unhealthy weight gain or even obesity.

So, start with these investigations, and then we can decide the next steps based on the results.

Hope I have solved your query. I will be happy to help you further.

Thank you.

Answered byDr. Neha Agarwal

Medically reviewed byiCliniq medical review team

Published At July 19, 2025
Reviewed AtJuly 19, 2025

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