With so much news and discussion focused on obesity in America, not much attention is being given to the 2% of the population who are underweight. Underweight is defined as having a body mass index (BMI) of less than 18.5. Health problems are associated with this weight status, though different problems from the ones facing the obese.
Women are four times more likely to be underweight than men, and the youngest (ages eighteen to twenty-four) and oldest (sixty-five and over) are nearly twice as likely to be underweight as other age groups. Furthermore, some people have difficulty gaining weight. And, while we all would like to be able to consume as many candy bars and butter pats as we want, these aren't the healthiest ways to go about adding pounds. (I'm on the thin side myself, and I've often had well-meaning friends urge me to remedy the situation with donuts, Ring-Dings, and buckets of lard.) Fortunately, there are ways to gain weight without long-term negative health repercussions.
Why Should People Be Concerned If They Are Underweight?
Being underweight could signify other underlying health problems. If an individual has experienced a recent weight loss without any changes in diet or is simply worried about being underweight, she should consult a physician. The explanation for your low weight might be a higher metabolic rate, but there could be other health problems you are unaware of, such as stress, parasitic infections, wasting diseases (cancer or AIDS/HIV), hyperthyroidism, anorexia nervosa, or excessive physical exertion.
Underweight can lead to impaired immune response to infection and female infertility. Amenorrhea, or loss of menstrual cycle, happens when women have too little body fat to produce female hormones, which can subsequently affect fertility. Dr. Rose Frisch, professor emerita at the Harvard School of Public Health, told the New York Times: "Something so small as a five-pound weight loss or gain around the threshold weight can turn menstrual cycles on or off...[severely] underweight women do not have the relative fatness necessary to have a viable infant." Low body fat has also been associated with asthma, arthritis, back problems, high blood pressure, diabetes, and thyroid disorders, all of which may be made still worse by smoking. Also, patients who are underweight and undergoing cancer chemotherapy have poorer outcomes.
Smoking and Being Thin
Underweight smokers are at a higher risk for cancer, bowel disorders, ulcers, and migraines. If you are a smoker who wants to gain weight, you should consider quitting, since many who do so experience weight gain (as noted in ACSH's booklet Cigarettes: What the Warning Label Doesn't Tell You). Note that this does not mean overweight people should start smoking, since a few lost pounds are not worth the increased likelihood of lung disease, heart disease, cancer, and other ailments.
Smokers tend to have leaner bodies than non-smokers and this is not due to exercising more or eating less, since smokers tend to be less active and eat the same amount as or more than non-smoking counterparts; instead, this weight differential is probably due to the fact that smoking increases the metabolic rate, the rate at which the body burns calories, by anywhere from two to ten percent. When smokers exercise, their metabolic rates increase even more than non-smoking counterparts who are physically active. If you are underweight and smoke, you have multiple reasons to give up the cigarette habit and get healthy.
How Does an Individual Gain Weight Healthfully?
Weight gain is not so easy and can be quite frustrating for those who are trying to bulk up. However, the rule for weight gain is simple: increase your caloric intake and eat more calories than you burn. Someone looking to gain a few pounds should be sure to eat three meals a day and two to four snacks, consuming a little something every two to three hours. These snacks should be of high caloric value and also provide healthy nutrition. One option, says ACSH's nutrition director Dr. Ruth Kava, is to snack on nutritional drink supplements (in addition to, not in place of, normal food), which are found at your local drug store and contain both a high number of calories and valuable nutrients.
Other ways to add calories to your diet include drinking vegetable juices, fruit juices, and milk, which have nutritional value and other potential health benefits, rather than consuming water. For example, cranberry juice believed to help the urinary tract system by preventing bacteria from adhering to the wall of the bladder is also a good source of calories and vitamin C. Milk provides calories, protein, and calcium, necessary for strong bones. Instead of eating corn flakes, opt for granola that is higher in fat, calories, and fiber. Finally, you can add cheese to your deli sandwich at lunchtime to increase fat and calories, while also providing your body with much-needed calcium.
Try to be more in tune with your body. If it is telling you that you are hungry, then eat! Some individuals may lack an interest in food and need to make a concerted effort to eat. To calculate how many calories you need to gain one to two pounds a week, check out the Healthy Body Calculator site. It is also a good idea to keep a food diary and write down everything you ingest throughout the day. Just as this is a good habit when you are trying to lose weight, it helps when your goal is to gain. It will increase your awareness of the calories you are consuming. Finally, try to hit all food groups within the Food Pyramid, eating sufficient servings of fruit, vegetables, dairy, and meats and starches, as well as sweets and heart-healthy fats, such as omega-3 fatty acids, found in fish and some oils.
It's Not Just the Food
Exercise will ensure that you add both muscle and fat to your body. Weight training three times a week can increase your muscle mass without burning off a large amount of the calories you are ingesting. If you are not eating enough because you are feeling stressed, exercise can help with this too relaxing you while also increasing appetite and thirst.
For those who are underweight, the key to reaching a healthy weight does not mean adopting the lifestyle habits of a couch potato or a diet based solely on candy bars. Healthy weight gain involves eating a variety of nutritious foods frequently and adopting an appropriate fitness program. For more personalized advice on suitable weight gain goals and other information, seek a registered dietician (R.D.) in your area by consulting the American Dietetic Association's website.
Karen Schneider is a research intern at the American Council on Science and Health.