Underweight | Office on Women's Health (2023)

Underweight | Office on Women's Health (1)

In today's world, thinness is often praised. But being underweight, when your weight is lower than what is considered healthy for your height, can be a sign of a serious health problem.Many different things can cause women to be underweight, includingeating habits, health problems, and medicines. Underweight can cause other health problems and problems getting pregnant. You can work with your doctor or nurse to help you reach a healthy weight.

How do I know if I’m underweight?

You can use the body mass index (BMI) to find out whether your weight is in a healthy or unhealthy range. BMI is a tool to estimate body fat. Find your BMI by typing your height and weight into this BMI calculator from the Centers for Disease Control and Prevention.

Women with a BMI of less than 18.5 are considered underweight. The average woman's height is 5 feet, 4 inches. If you weigh 107 pounds or less at this height, you are considered underweight with a BMI of 18.4. A healthy weight range for that woman would be 108 to 145 pounds.

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BMI is just one way to measure healthy weight. Some women have a low, but still healthy weight. Talk to your doctor or nurse about what is a healthy weight for you.

What causes women to be underweight or to lose weight suddenly?

Some women are naturally thinner than others. But certain health problems, certain medicines, or other serious problems can lead to chronic (long-term) underweight or sudden weight loss. These include:

  • Health problems that affect metabolism, such as overactive thyroid or diabetes
  • Health problems that affect the digestive system, such as celiac disease or Crohn's disease
  • Other health problems, such as viral hepatitis, cancer, COPD, or Parkinson's disease
  • A lack of appetite due to stress, illness, or substance use
  • Medicines that may cause nausea or lack of appetite
  • Eating disorders, such as anorexia
  • Over-exercising, such as for athletic training
  • Age. Underweight can especially be a problem for older women who may have loss of appetite, problems chewing, or a health problem.1
  • Genes. Underweight can run in families.

Also, there may be a link between underweight in childhood and developing an eating disorder in adolescence.2

How common is underweight?

In the United States, about 2% of women have underweight.3


How does underweight affect a woman’s health?

Underweight raises your risk for serious health problems. Some women have a low, but still healthy weight. But if you have experienced sudden weight loss or are not eating enough to keep your body working, you may develop serious health problems, including:

  • Problems with your menstrual cycle. A regular period is a sign of good health. Losing too much weight can cause periods to be less regular or stop completely. This can happen if your body fat drops so low that you stop ovulating, or releasing an egg from an ovary each month. This is especially true if you are losing weight because you are not eating enough or because you are exercising too much, which may be signs of an eating disorder like anorexia nervosa.
  • Problems getting pregnant. Problems with your menstrual cycle can make it harder to get pregnant, especially if your period stops completely. If you do not get a period, then you are probably not ovulating, or releasing an egg from an ovary each month.
  • Osteoporosis. Underweight increases your risk of osteoporosis later in life. Osteoporosis is a condition that causes bones to become weak and break easily.
  • Malnutrition. Malnutrition means your body is not getting enough vitamins and minerals to do what it needs to do. This can cause serious health problems, such as a weaker immune system and anemia. Anemia happens when your blood cannot carry enough oxygen to your body because of a lack of iron. If you have anemia, you may feel dizzy, lightheaded, weak, or tired.
  • Depression. Studies show that depression is more common in women who are underweight than women who are at a healthy weight.4,5

Women who are underweight may also be more likely to die early than people of normal weight.6 Women who are underweight earlier in adulthood may also experience menopause sooner than women who stayed a normal weight.7

How can I gain weight in a healthy way?

Talk to your doctor or nurse about an eating plan that can help you gain weight in a healthy way. To gain weight in a healthy way, you should focus on getting enough nutrients — calories, vitamins, and minerals — for your body to work correctly. To reach a healthy weight, you should eat foods from all of the food groups with a calorie amount that is healthy for your current weight. Your doctor or nurse can tell you how quickly to gain weight in a safe and healthy way. Gaining weight suddenly, or by eating a lot of sweet or fatty foods, is not healthy.

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If you need to gain weight because of an eating disorder, work with your doctor or nurse to gain weight safely and treat the eating disorder. If the eating disorder is not treated, it may come back or continue and cause health problems. Gaining weight too suddenly, with an eating disorder, can cause serious heart problems and other health concerns.

Because many Americans are overweight, there are many resources geared toward losing weight. But some of these resources can also provide guidance for you to gain weight in a healthy way. See the list of resourcesat the end of this page to learn more.

Should I stop exercising if I’m underweight or losing weight too quickly?

Maybe. People who are underweight due to an eating disorder should not exercise unless their doctor tells them to. Physical activity is important for your health, muscle strength, balance, and flexibility.8 Your doctor or nurse can help you develop an exercise plan that is healthy and safe for a person of your current weight.

If you normally do high-intensity aerobic workouts, your doctor or nurse may talk to you about more moderate or less vigorous aerobic, strength training, and flexibility exercises.

When should I talk to a doctor or nurse about my weight?

If you are worried about your weight, talk to your doctor or nurse.

Your weight can affect your health. Your weight can also make it harder to get pregnant. Talk to your doctor or nurse if you are underweight and have period problems or symptoms of malnutrition, such as extreme tiredness, headaches, or hair loss.

Your doctor or nurse will ask you questions and may do tests to learn more about what is causing your symptoms or weight loss. Your doctor or nurse may suggest making changes in your eating and exercise habits, depending on the cause of your weight loss.

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Did we answer your question about underweight?

For more information about underweight, call the OWH Helpline at 1-800-994-9662 or check out the following resources from other organizations:


  1. Stajkovic, S., Aitken, E.M., Holroyd-Leduc, J. (2011).Unintentional weight loss in older adults.CMAJ;183(4): 443-449.
  2. Cimino, S., Cerniglia, L., Almenara, C.A., Jezek, S., Erriu, M., Tambelli, R. (2016).Developmental trajectories of body mass index and emotional-behavioral functioning of underweight children: A longitudinal study. Scientific Reports;6: 20211.
  3. Centers for Disease Control and Prevention (CDC) National Center for Health Statistics (NCHS). (2018).Prevalence of Underweight Among Adults Aged 20 and Over: United States, 1960–1962 Through 2015–2016. Hyattsville, MD.
  4. Mukherjee, S. (2013).Comparing Adult Males and Females in the United States to Examine the Association between Body Mass Index and Frequent Mental Distress: An Analysis of Data from BRFSS 2011.Psychiatry Journal; 2013: 230928. doi:10.1155/2013/230928.
  5. de Wit, L.M., van Straten, A., van Herten, M., Penninx, B.W., Cuijpers, P. (2009).Depression and body mass index, a u-shaped association.BMC Public Health; 9:14. doi: 10.1186/1471-2458-9-14.
  6. Flegal, K.M., Graubard, B., Williamson, D., Gail, M.H. (2005).Excess Deaths Associated With Underweight, Overweight, and Obesity.JAMA: The Journal of the American Medical Association;293(15): 1861-1867.
  7. Szegda, K.L., Whitcomb, B.W., Purdue-Smithe, A.C., et al. (2017).Adult adiposity and risk of early menopause.Human Reproduction.
  8. U.S. Department of Health and Human Services. (2018).Physical Activity Guidelines for Americans (PDF, 14.2 MB).
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What happens when a woman is underweight? ›

Underweight increases your risk of osteoporosis later in life. Osteoporosis is a condition that causes bones to become weak and break easily. Malnutrition. Malnutrition means your body is not getting enough vitamins and minerals to do what it needs to do.

What are 3 risks of being underweight? ›

If you are underweight, you may be at greater risk of certain health conditions, including malnutrition, osteoporosis, decreased muscle strength, hypothermia and lowered immunity. You are more likely to die at a younger age. Underweight women have less chance of becoming pregnant than women who are a healthy weight.

What is considered underweight for a woman? ›

If your BMI is less than 18.5, it falls within the underweight range. If your BMI is 18.5 to 24.9, it falls within the normal or Healthy Weight range. If your BMI is 25.0 to 29.9, it falls within the overweight range. If your BMI is 30.0 or higher, it falls within the obese range.

Is it OK to be underweight but healthy? ›

Being underweight is not good for you. It could cause: Nutritional deficiencies: if you're underweight, it's likely that you're not eating a healthy, balanced diet, which can lead to you lacking nutrients that your body needs to work properly.

What are 3 reasons people are underweight? ›

A person may be underweight due to genetics, improper metabolism of nutrients, lack of food (frequently due to poverty), drugs that affect appetite, illness (physical or mental) or the eating disorder anorexia nervosa.

Should I exercise if I'm underweight? ›

A lot of people believe that because you are underweight, you should not exercise or give your body any rigorous physical activity. But it is not true. To gain weight and maintain the ideal frame you need to have a proper caloric food intake along with a training regime.

Can being underweight cause hormonal imbalance? ›

The primary way that being underweight compromises a woman's fertility is by creating an imbalance in hormones that play a role in ovulation. Underweight women are more likely to miss periods or have an irregular menstrual cycle, both of which make it much more difficult to conceive.

What body systems are affected when a person is underweight? ›

A body mass index, or BMI, below 18.5 means a person is underweight and this is associated with health complications such as bone loss, decreased immunity, cardiac problems, and infertility.

What is severely underweight? ›

Severely underweight - BMI less than 16.5kg/m^2. Underweight - BMI under 18.5 kg/m^2. Normal weight - BMI greater than or equal to 18.5 to 24.9 kg/m^2.

How much should a 5'2 female weigh? ›

Height and Weight Chart
5'97 to 127 lbs.128 to 152 lbs.
5' 1"100 to 131 lbs.132 to 157 lbs.
5' 2"104 to 135 lbs.136 to 163 lbs.
5' 3"107 to 140 lbs.141 to 168 lbs.
17 more rows

How does being underweight affect your mental health? ›

Being underweight has a profound effect on social functioning. There is a tendency to become inward-looking and self-focused. This is exaggerated by the heightened need for routine and predictability, and difficulty being spontaneous. As a result people withdraw socially and get used to this way of living.

How long does it take to gain weight if underweight? ›

Weigh yourself on a weekly basis, aiming for a goal of gaining 0.25–0.5% of your body weight per week. For example: A 175-pound (79-kg) man might aim to gain 0.4–0.8 pounds (0.2–0.4 kg) per week. A 135-pound (61-kg) woman might aim to gain 0.3–0.6 pounds (0.14–0.28 kg) per week.

Should I gain weight if I'm underweight? ›

If you are underweight, a healthy amount of weight to gain is usually ½ to 1kg per week, until you reach your target healthy weight. For people who are losing weight unintentionally and are in the healthy, overweight or obese BMI categories, a good goal would be to aim for weight maintenance.

What are the benefits of being underweight? ›

15 Nov 35 Surprising Benefits of Weight Loss
  • More energy. Carrying extra weight requires the body to use a lot of energy. ...
  • Fewer headaches. ...
  • Stress may disappear. ...
  • Balanced mood. ...
  • Saving money. ...
  • Work gets easier. ...
  • Better social life. ...
  • Better immune system.

How does it feel to be underweight? ›

Underweight Symptoms

People who are underweight may feel extremely fatigued as well as have low blood pressure and possibly even low blood sugar. They also may feel dizzy, nauseous, and cold.

Why don't I gain weight when I eat a lot? ›

A Fast Metabolism

This rate changes from person to person based on a number of factors, including genetics, diet, and level of activity; if you eat a lot but don't gain weight, it could be because your BMR is high, so you burn calories at a greater rate than most people.

How can an underweight woman gain weight? ›

Base your meals on starchy carbohydrates, such as wholemeal pasta, brown rice or potatoes. Have at least 5 portions of fruit and vegetables a day. Have some lean protein (from lean meat, fish, beans and pulses). Have some dairy or dairy alternatives each day – have whole milk until you build your weight back up.

Which approach is recommended for underweight people gaining weight? ›

Load up on fats: If you're healthy but underweight, or an athlete who wants to gain muscle mass, one of the best ways to gain weight is to fill up on healthy fats, such as nuts and nut butters, avocados and fatty fish like salmon.

What happens to hormones when underweight? ›

Many women and men in our culture believe that being underweight is healthier than being overweight. However, being too thin (BMI less than 18.5) also has health consequences, including infertility. When you're too thin, have an eating disorder, or work out excessively, your body stops producing estrogen.

How does being underweight affect menstrual cycle? ›

If you lose too much weight, you may stop having periods altogether. When you do not have a period for three months (and are not pregnant), it is known as amenorrhea. Being underweight causes a change in hormone levels, including a drop in estrogen. This interrupts ovulation and causes you to miss your period.

Can being underweight reduce estrogen? ›

Some of the estrogen in your body is produced by your body fat. If you're overweight or obese, you may have too much estrogen. If you're underweight, you may have too little estrogen. Both of these situations can interfere with pregnancy.

What are 5 reasons underweight? ›

Causes of being underweight include:
  • Family history. Some people have a naturally low BMI due to physical characteristics that run in their family.
  • A high metabolism. ...
  • Frequent physical activity. ...
  • Physical illness or chronic disease. ...
  • Mental illness.

How do I fix severely underweight? ›

Here are some healthy ways to gain weight when you're underweight:
  1. Eat more frequently. When you're underweight, you may feel full faster. ...
  2. Choose nutrient-rich foods. ...
  3. Try smoothies and shakes. ...
  4. Watch when you drink. ...
  5. Make every bite count. ...
  6. Top it off. ...
  7. Have an occasional treat. ...
  8. Exercise.

Can being underweight be fatal? ›

The study authors also examined mortality rates in the 14% of patients (n = 542) who had sepsis. Again, underweight patients had the highest risk of 28-day mortality (15%), compared with normal weight (7%), overweight (4%), and obese patients (5%) (P = 0.003).

How much should a 5 0 female weigh? ›

What's my ideal body weight and BMI?
HeightIdeal WeightIdeal Weight
5′ 0″95 – 117 lbs.90 – 110 lbs.
5′ 1″101 – 123 lbs.95 – 116 lbs.
5′ 2″106 – 130 lbs.99 – 121 lbs.
28 more rows

Does being underweight increase anxiety? ›

Women who are extremely underweight or obese are likely to be at an increased risk of developing common mood disorders like depression and anxiety, as a result of low feel-good neuroactive steroid, finds a study.

Can being underweight make you depressed? ›

According to researchers at the Seoul National University of Medicine, yes it does. In the first study to link depression with underweight body types, the research found that both men and women can be impacted by negative thoughts about being too skinny.

Is underweight considered anorexic? ›

A person does not need to be underweight to have anorexia. Larger-bodied individuals can also have anorexia. However, they may be less likely to be diagnosed due to cultural stigma against fat and obesity. In addition, someone can be underweight without having anorexia.

How many calories should an underweight person eat? ›

As a guide, consuming 300–500 calories more than the body burns on a daily basis is usually sufficient for steady weight gain. For more rapid weight gain, a person may need to consume up to 1,000 calories more per day.

What are the symptoms of being underweight? ›

People who are underweight or undernourished often experience symptoms such as fatigue and lethargy as well as low blood pressure, heart rate and blood sugar levels, which can cause night sweats, having cold fingers and toes and muscle problems, says Judy Simon, a registered dietitian nutritionist at UW Medicine who ...

What should you do if you're underweight? ›

Choose high-calorie, protein-dense foods.

Meats, cheeses, and nutritious whole-grain, complex carbohydrates are excellent choices. While simply eating a lot of nearly anything will make you gain weight, care must be taken to also answer the nutritional deficiencies that are part of being underweight.

What is the most common cause of being underweight? ›

People who are underweight typically are not getting enough calories to fuel their bodies. Often, they are also suffering from malnutrition. Malnutrition means you are not taking in enough vitamins and minerals from your food.

Can you get sick from being underweight? ›

There are certain health risks associated with being underweight or having poor nutrition. These risks include: malnutrition, vitamin deficiencies, or anemia. osteoporosis from too little vitamin D and calcium.

What deficiency causes underweight? ›

A deficiency of vitamin D can lead to low weight gain and malabsorption of calcium in the body. This in turn leads to weak and fragile bones and conditions such as osteoporosis. A deficiency of vitamin E affects the skin and hair of the person.

What is the best drink to put weight on? ›

Top 6 Weight Gain Drinks
  1. Protein Shakes. Protein is a key ingredient in many high-calorie drinks for weight gain. ...
  2. Smoothies. Smoothies are another great way to boost your calorie intake and increase your overall nutrient intake. ...
  3. Juices. ...
  4. Milkshakes. ...
  5. Beverages. ...
  6. Vegetable Smoothies/Shakes.
18 May 2022

How skinny is too skinny? ›

Too Skinny: What BMI is Considered Underweight? From a clinical perspective, an individual is considered “too skinny” if they are deemed underweight. According to the Centers for Disease Control, an individual is underweight if their Body Mass Index (BMI) is below 18.5 [1].


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