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Underweight, Low BMI Body Mass Index Reasons


Being underweight is equally bad for health just as in the case of suffering from overweight. Lower weight also poses great risk for men and women. People are said to be under-weight if their Body Mass Index (BMI) is below 18.5 points. People with 25 points are considered overweight and over 30 are considered obese. BMI scale considers only height and weight and doesn't’t take muscle mass into account. Under-weight is common among women and girls. Under-weight causes many risks like infections, osteoporosis and fractures, cause fertility problems, sarcopenia and dementia. Under-weight is caused by many factors, some of which are physical, while others are psychological.

Physical causes of Underweight:

Many illnesses cause temporary weight loss. If a man suffers from flu with a high temperature, he may lose a few kilos, but probably gain back when he gets well again. There are five major medical reasons for pronounced weight loss and underweight:

  1. Hyperthyroidism:

The thyroid gland produces the thyroxine hormone. If the production of thyroid hormone produce is normal, the conditions of health, weight and metabolism will be well. If thyroid gland produces thyroid in more quantities, the metabolism and many body functions such as body temperature, heartbeat, etc... will be deranged and loss in weight occurs. This condition is called hyperthyroidism, overactive thyroid or thyrotoxicosis and is associated with symptoms such as enlarged thyroid gland causing a goiter or bulging at the base of the neck, nervousness, tiredness, weight loss, increased body temperature with excessive sweating and increased heart rate.

  1. Cancer:

Cancer can also be the cause for rapid weight loss, lack of appetite and nausea.

  1. Tuberculosis:

Tuberculosis causes rapid weight loss, night sweats, coughing, malaise and tiredness.

  1. Diabetes:

Diabetics tend to suffer from weight loss, excessive weight loss, tiredness, excessive urination and thirst are all symptoms of diabetes.


Psychological cause of Underweight:

One of the most important causes of Less-weight is depression. Depression not only often has a reduced appetite, but also causes to lose weight.

Other Factors:

There are also a number of other factors that could be causing weight loss:

  • Excessive Stress: Excessive stress may result in less eating, lack of appetite and nausea.
  • Enzyme deficiencies: Deficiencies of digestive enzymes may also cause weight loss.
  • Immoderate Exercise: over doing exercise sessions also causes under-weight.
  • Other medical conditions such as cystic fibrosis, coeliac disease is associated with under-weight.

If you experience sudden weight loss or struggle to gain weight, you need to have a medical examination by expert professionals.

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