Side Effects of Being Underweight

Being too thin seems an enviable condition, given the rate of overweight and obesity in today's society. But with this unhealthy weight comes a host of potential complications. In addition to your not feeling your best, your body may not be able to perform optimally and compromise your health. Whether you're underweight due to an illness, surgery, a genetically fast metabolism or eating an unbalanced diet, it's a situation you can correct with more calories, appropriate activity and guidance from a medical professional. You're considered underweight if your body mass index, a relationship between your height and weight, measures less than 18.5.

Being too thin means your immune system can't operate strongly; you're more vulnerable to getting sick or acquiring infections. You might find yourself susceptible to colds and the flu, and recovery from such ailments slow. If you're recovering from an illness or surgery, being too thin slows the healing process. A meta-analysis published in a 2014 issue of the Journal of Epidemiology and Community Health determined that people with a BMI of 18.5 or below have nearly twice the risk of dying early than someone with a normal BMI.

Your immune system needs a quality influx of vitamins and minerals to operate most effectively. When you're underweight, you may not be getting all or enough of these nutrients, including vitamins A, C, D and E, as well as the minerals iron, selenium and zinc. Hair loss and overall weakness, due to diminished muscle mass, may also occur and contribute to frailty.

Underweight girls, in particular, can experience hormone disregulation. They may menstruate irregularly, or not menstruate at all. Being underweight is a form of stress that causes your body to alter hormone production, so it can focus on other essential body functions that keep you alive. With abnormal hormonal flow, you're at greater risk of osteoporosis.

An underweight status can complicate pregnancy or make it difficult to get pregnant. Your body likely senses that it doesn't have enough body fat or isn't receiving enough nutrients to support another life and that this is not a good time to reproduce. Research presented at the 2011 American Society for Reproductive Medicine, or ASRM, conference confirmed that women with a BMI of between 14 and 18 had only a 34 percent chance of delivering a healthy baby.

Too slight of a body size could be an indication that your diet is nutritionally insufficient or you have a condition, such as Celiac Disease, that prevents you from absorbing nutrients effectively. This can put you at risk of iron-deficiency anemia or amino acid deficiency. Nutritional deficiencies rob you of optimal energy, so you feel lethargic or weak. Your complexion may dull, your hair dry out, muscle mass diminishes, your brain feels foggy, and it's hard to sleep.

Peer pressure and life stress are hard enough; you don't want to have to deal with negative comments about your appearance. Being too thin can make you feel self-conscious and prevent you from doing the things you want, such as playing certain sports. Not everyone has the same body type, and you can't turn from a lanky basketball player into a stocky lineman with changes to your diet and exercise program, but you can become the healthiest possible for you.

Check with your medical provider first to make sure you don't have an underlying condition, such as an autoimmune disorder or digestive malabsorption issues, that are causing you to lose too much weight. The only way to put on pounds is to eat. Avoid unhealthy foods such as sweets and processed snacks, as you're still vulnerable to the diseases that can occur from consuming too much sugar and refined grains even when underweight.

Add 250 to 500 calories a day in healthy foods, such as lean protein, whole grains and unsaturated fats. A large dollop of peanut butter on a banana, a handful of nuts between lunch and dinner, or a smoothie made with fresh fruits, yogurt and ice can all add healthy calories in a delicious way.

Being physically active helps boost your appetite. Get out and walk or ride a bike for 20 to 30 minutes on most days. Add resistance training a couple times per week to help build healthy muscle mass. These measures can help you gain a reasonable and healthy 1/2 to 1 pound per week.