Underweight – causes & complications


When you are underweight, then it can make many health concerns to the individual as being overweight can. When the person is underweight, then their body may not be getting the nutrients which it needs to build healthy bones, skin and hair. There are some people who have a genetic background or medical illness which prevents them from putting on weight but there are interventions doctors which can help a person to gain a weight in natural way.

It is recommended the usage of BMI (body – mass index) for people to calculate if they are underweight, they have healthy weight or they are overweight. BMI is considered as a good measure for person’s weight because it compares the weight to the height. If someone has 170 pound, then this person may not be overweight if he or she is very tall but it can be overweight if he or she is very short. The BMI’s measures include

  • You are underweight if you are less than 18.5
  • You have normal/healthy weight if you are 18.5 to 24.9
  • You are overweight if you are 25.0 to 29.9
  • You are obese if you are 30 or higher



There are many different reasons why the person is underweight. In some cases, multiple underlying causes can be related. Here are some causes of underweight:

  • Mental illness: The poor mental health can affect a person’s ability to eat. Some of the mental illnesses include bulimia, anemia, eating disorders, obsessive – compulsive disorder, anxiety and depression. Each of the mentioned conditions can affect the person’s body image and appetite.
  • Physical illness or chronic disease: There are some diseases which can cause diarrhea, vomiting and nausea and these symptoms are happening constantly so the affected person has difficulties in gaining weight. Also, there are other conditions which can decrease the person’s appetite so they do not feel like eating. Some of these diseases include ulcerative colitis, Crohn’s disease, thyroid disorders, diabetes and cancer.
  • Frequent physical activity: It is known that athletes or people who engage in high levels of physical activities, such as runners, can burn significant amounts of calories which are resulting in low body weight.
  • A high metabolism: When the person has a high metabolism, then he or she may not gain much weight even when he or she is eating high – energy food.
  • Family history: There are some people who have a naturally low BMI due to physical characteristics which run in their families.


When you are underweight, then you can have side effects from it but not all people who are underweight will experience side effects for sure. Here are some complications caused by being underweight:

  • Getting sick frequently: When the person does not get enough energy from the diet to maintain a healthy body weight, then he or she may also not be getting enough nutrients to fight infections. As a result from this, the affected person gets sick more frequently and common illnesses, such as cold, can last longer than they usually would.
  • Skin, hair or teeth problems: When the person does not get enough nutrients in the daily diet, then he or she can notice physical symptoms, such as poor dental health, dry skin, hair loss or thinning skin.
  • Osteoporosis: There was one study in 2016 in which was said that being underweight can increase the risk of women for getting osteoporosis and this is a condition where the bones are brittle and they have increased risk of breaking.
  • Anemia: The person who is underweight is having more chances to have low blood count which is known as anemia. This condition causes fatigue, headaches and dizziness.
  • Slow or impaired growth: When young adults are underweight and when they are not getting enough nutrients, then the affected person may not develop as expected.
  • Feeling tired all the time: When the person is not getting enough calories to maintain a healthy weight, then this can make the person to feel fatigued.
  • Premature births: There are some studies in which are said that women who are pregnant and underweight have increased risk for pre – term labor and this means that she will have a baby before 37 weeks.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.