Thanks for your question. There are many different ways to classify weight. Most ways of classifying weight look at your age, weight, and height. It’s important to know that everyone is meant to be a different body size and shape, so the most useful way to know if you are at a healthy weight now is by seeing how you’ve grown (weight and height) since you were a baby. There is no “correct” weight for a certain age, only a healthy weight range for each person based on their personal growth history.
In general, teens are supposed to gain some weight as they get older to help fuel their body as it goes through puberty. To gain weight you have to take more energy in (through consuming food and drinks) than the energy you spend (through exercise or physical activity). The American Academy of Pediatrics recommends that all teens get 60 minutes (or more) of physical activity a day.
Also, if you are throwing up after eating, this can be a sign that something more serious may be going on. This can also be the reason why it may be hard to gain weight.
We recommend talking to your health care provider. They can let you know if you are at a healthy weight. They can also help determine whether there are any medical problems that are causing you to throw up after eating.
Our health guides are developed through a systematic, rigorous process to ensure accuracy, reliability, and trustworthiness. Written and reviewed by experienced healthcare clinicians from Boston Children's Hospital, a Harvard Medical School teaching hospital and consistently ranked as a top hospital by Newsweek and U.S. News & World Report, these guides combine clinical expertise, specialized knowledge, and evidence-based medicine. We also incorporate research and best practices from authoritative sources such as the CDC, NIH, PubMed, top medical journals, and UpToDate.com. Clinical specialists and subject matter experts review and edit each guide, reinforcing our commitment to high-quality, factual, scientifically accurate health information for young people.