Being underweight may not be as common as being overweight is, but it carries its own set of health risks. Some people are naturally underweight and have difficulty adding pounds, while other might have an eating disorder that puts them in a lower weight range. Gaining weight can help counteract these health issues, but should be done under the supervision of your physician.
Without adequate nutrition, your body's immune system may not function properly. Vitamins A and C are of particular importance to healthy immunity, and being underweight may mean you don't have enough reserves on hand to prevent illnesses from the common cold to cancer. Lowered immunity makes it difficult for your body to fight off viruses and bacteria that contribute to disease and sickness. Adding pounds healthfully, by eating foods from each of the food groups, improves immunity and increases nutrient stores.
Changes in Core Body Temperature
Many people associate being cold all the time with an eating disorder, but anyone who is underweight may have trouble regulating body temperature. At a healthy weight, your body is insulated with a layer of fat that keeps you warm. Being underweight for any reason may result in feeling chilled, even if the outside air is warm. Adding a few pounds can help counteract this problem and aid in maintaining normal body temperatures.
People who don't weigh enough are often susceptible to issues associated with nutritional deficiencies. For example, some people who are underweight become deficient in calcium, which is vital for keeping your bones strong and healthy. Potassium is another nutrient you may be lacking enough of if you're underweight. This nutrient is important for a healthy heart, and low levels are dangerous. Nutrient deficiencies may also interfere with lung function, joints, mental health and digestion.
Lack of Energy
If your body doesn't have enough fat and nutrient stores, you might feel weak. This lack of energy may make it difficult to get through day-to-day tasks at work, home or school. Lack of energy is likely due to a lack of iron in your blood, a nutrient that helps prevent anemia. Anemia saps your energy. Simply increasing your daily food intake can help normalize your iron levels, increasing your energy.
Women are more likely to be overweight than men, though some males also struggle with the problem. Females who don't weigh enough may not menstruate on a regular basis or at all. This might interfere with fertility now and down the road because your body's reproduction isn't regulated normally, which can skew ovulation and make it difficult to sustain a healthy pregnancy.