Top 5 Major Causes of Underweight | Risks and Treatment


There are several causes of underweight.

Both medical and genetics conditions can cause underweight.

Inappropriate dietary choices, unhealthy habits such as skipping breakfast, a mostly sedentary lifestyle, and metabolic changes can all contribute to unhealthy weight loss.


How do you know your underweight?

Visit nearby healthcare Centre for body mass index (BMI) checkup.

If your BMI is under 18.5, then you may be underweight.

Normal weight is from 18.5 to 24.9 and overweight is from 25.0 to 29.9 and obese is from 30.0 and above.

Here are some of the causes of underweight.

1. Medical conditions

Physical illness can lead to unhealthy weight loss.

Regular nausea, vomiting, and diarrhea hinder growth and development.

Furthermore, diseases such as cancer, diabetes, thyroid disorders, and digestive conditions may result in unnecessary weight loss.

  • Cancer, for instance, someone suffering from cancerous tumors regularly burns a high quantity of calories and may result in a large amount of muscle mass loss.
  • Diabetes: when suffering from type 1 diabetes or uncontrolled diabetes. This can lead to a high amount of loss of calorie and water in the body resulting in severe weight loss.
  • Disease infections such as HIV/AIDS, tuberculosis are very harmful, if not timely prevented or treated can lead to weight loss.
  • Thyroid problems: thyroid can cause an increase in metabolism, especially when you have an overactive thyroid. It leads to dry skin,
  • Eating disorders such as vomiting, diarrhea, nausea, may result in weight loss also celiac disease, the gluten intolerance may result in underweight.

2. How Genetics Causes Underweight?

Family history may cause low BMI.

The genes inherited can directly influence the general body functions and weight.

Gene can also result to a person’s susceptibility to weight loss.

Genetic code controls the growth of cells and expires.

Therefore, changes in the genes can lead to alteration of cell’ DNA and cancer can develop.

Furthermore, genes can affect the cells’ production of proteins, being that proteins carry out various functions in order for cellular growth and division.

The physical characteristic of a person that runs in their family is a key to underweight in some people.

3. Mental illness

Another causes of underweight are depression.

It is one of the very dangerous things; it can cause loss of weight.

Anxiety and obsessive-compulsive disorder are other mental illness that can hinder your body metabolism and can lead to loss of appetite.

Mental illness reduces the intake of calories and other healthy balanced diets that are required for growth of body mass.

4. Frequent physical activity

Continuous exercises for the long term may result in unwanted weight loss.

For instance, athletes or people who engage in high levels of physical activity may reduce excess body fats and calories that result in low body weight.

5. Inappropriate dietary choices

Poor diet is another cause of underweight.

For instance, eating an unbalanced diet, that is consuming inappropriate proportions, and the wrong amount of food and drinks may result in unhealthy body weight.

Not eating optimal food nutrient such as lack of enough protein, calories, vitamins, mineral, carbs, fluids may result in severe weight loss.

In addition, skipping a certain meal during the day may result in underweight.

Here are 8 common side effects of underweight

Underweight is associated with an array of health hazards.

However, not all people who are underweight have the symptoms.

The following are some of the risks of underweight.

  • Unhealthy Skin, hair, or teeth

Lack of enough minerals and vitamins, such as iron, zinc, B vitamins, and vitamin B12 may result in hair loss, dry skin, thinning skin, weak teeth, or dental problems.

  • Frequent sickness

 Being underweight may result in regular sickness, and common illnesses, such as a cold, which can prolong.

Being underweight is associated with a lack of enough nutrients in the body.

Therefore, white blood cells cannot effectively defend the body against disease infection.

  • Recklessness

 Feeling fatigued due to a lack of enough calories in the body.

Calories is a major energy provider and when it is insufficient in the body, you may feel weak and tired all the time.

  • Osteoporosis

This is a condition that results when the body loses excess bone or make too little bone.

Being underweight may increase the chances of osteoporosis.

In addition, lacks enough mineral, may result in weak bones and which can break easily.

  • Anemia

 Being Underweight can lead to anemia.

Lack of enough iron in the bone marrow may lead to low blood counts in the body causing dizziness, headaches, and fatigue.

  • Irregular periods

 Most women who are underweight may have menstruation problems such as unpredicted periods which sometimes stop for a while.

It may lead to delay of an adolescent’s first period.

Irregular or absent menstruation can cause infertility.

  • Premature births

Studies reveal that a woman who is pregnant and underweight is at a higher risk for premature birth.

In other words, giving birth before 9 months or maturity of the newborn.

  • Slow or impaired growth

Growth impairment may be as a result of inadequate nutrients or consuming foods that lack growth-promoting nutrients.

Being underweight is one of the causes of impaired growth.

Treatments of underweight

To get rid of being underweight, you need to eat a healthy, balanced diet, including snacks, the high protein and whole-grain carbohydrate snacks in your daily meals.


Eat often throughout the day and add calorie-dense food sources to the existing meal.

Frequent eating results in weight gain.


Especially, when you eat silver almonds, chia seeds, and nut butter.

Avoid foods with a low amount of calories in your diet.

While eating high-calorie foods may cause a person to gain weight.

When you are underweight, it is advisable to avoid foods that are high in sugar and salt.

Visit healthcare professional such as dietitian or doctor, when you tried to gain weight but failed or experiencing any effects of ill health. 

About Victor Tannos

Vick is a researcher, freelancer, content writer, and lifelong learner with an ongoing curiosity to learn new things. Vick uses that curiosity, combined with his experience as a freelance to write about valuable topics on health, fitness, and lifestyle.

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