Underweight: A Heavy Concern
By Meghan A.T.B. Reese
Today’s Dietitian
Vol. 10 No. 1 P. 56

Overly thin people may be the envy of those who struggle to shed pounds, but as dietitians know, those who are significantly underweight risk infection, osteoporosis, and other medical conditions. Helping clients gain is crucial and starts with targeting a healthy weight.

With the obesity epidemic spreading at an alarming rate, it’s not unusual for dietetics and weight loss counseling to seem synonymous. However, despite the climbing number of Americans who are overweight or obese, there is also a segment of the population that is underweight. It’s easy to wonder how anyone could possibly struggle to gain weight when so many have unwittingly figured that out on their own. But there are many facing the difficulty of gaining weight and in need of professional help to do so.

The Skinny on Underweight
The American Dietetic Association (ADA) defines the ideal body mass index (BMI) as between 20 and 25. Thus, anyone below that range would be considered underweight and those with a BMI from 18.5 to 17.5 extremely underweight. According to Elena Blanco-Schumacher, RD, a clinical dietitian within the Christiana Care Health System at the Helen F. Graham Cancer Center in Wilmington, Del., 8% to 9% of the population is, by these standards, underweight.

While being underweight often appears preferable to being overweight, the reality is that—just as with obesity—being overly thin has risks and repercussions. Blanco-Schumacher notes that those who are underweight are prone to infection due to weak and easily compromised immune systems and tend to have low muscle mass, hair loss, and in some cases disrupted hormone regulation. Being underweight can also derail intake and absorption of vital nutrients, including amino acids, vitamins, and minerals, leading to increased risk of osteoporosis and anemia. In addition, underweight women are prone to amenorrhea and possible pregnancy complications.

There is a plethora of reasons why people may become underweight, and there are as many treatment courses as there are causes. “There’s no one size fits all or magic bullet. You need to tailor a plan based on each individual person,” Blanco-Schumacher says. Being underweight, whether or not weight is lost intentionally, results from a variety of factors, some psychological, some physiological.

Physical origins of underweight include genetics and illness. Those with “lean genes” may have a higher metabolic rate, Blanco-Schumacher says, but should be wary of excessive weight loss. “High risk for underweight is weight loss greater than 2% total body mass in one week; 5% in one month; 7.5% in three months; and 10% in six months,” she says. Some bouts with the flu or other viruses can cause unprompted weight loss, and many medications can suppress appetite or actually cause weight loss. Patients should check with their pharmacist if they have recently started a new medication and are now experiencing otherwise unexplained weight loss. Deficiencies of digestive enzymes and/or stomach acid may also contribute to weight loss and hamper attempted gains.

Anorexia likely comes to mind when considering underweight, but excessive stress may not. Yet many people under stress experience weight loss due to a lack of appetite or nausea. Another major psychological cause of underweight is depression. Individuals suffering from depression often present with a reduced appetite and rapid weight loss; in these cases, advice from a psychologist or counselor should be sought in addition to guidance from a dietitian.

Wasting Diseases
Several major illnesses foster pronounced weight loss and underweight, including hyperthyroidism and—perhaps surprisingly, since it is often related to obesity and overweight—diabetes. Then there are the wasting diseases such as tuberculosis, Lou Gehrig’s disease, multiple sclerosis, and cancer. These conditions are called wasting diseases because patients literally shrink away. Patients with wasting generally lose muscle mass, not fat, as the body burns up muscle tissue for the protein needed to fight inflammation in those with heart conditions and cancer. Since wasting can be a sign of disease progression, it should be a red flag for clinicians.

While not completely understood, the correlation between disease and wasting has many causes, including drug- or illness-associated side effects such as nausea and appetite loss; infections, which increase calorie needs; oral infections, which complicate eating or swallowing; and debilitating fatigue, which makes daily chores such as shopping and cooking difficult. Intestinal malfunction may lead to an inability to absorb nutrients and can contribute to weight loss. Metabolic changes, including the number of calories patients expend at rest or during physical activity, also affect weight loss.

HIV/AIDS, another wasting disease, also requires individualized nutrition care plans as part of medical management. According to research conducted at Tufts University, “All HIV-positive patients, including those on antiretroviral therapy, can develop wasting.” Dietitians should routinely monitor patients for changes in body mass and weight and look for lipodystrophy or a change and redistribution of fat in patients’ body shape.

In the position paper “Position of the American Dietetic Association and Dietitians of Canada: Nutrition Intervention in the Care of Persons with Human Immunodeficiency Virus Infection,” the ADA states, “A well-nourished HIV-positive person is more likely to be able to withstand the effects of HIV infection.” Also, “Nutritional status, specifically the maintenance of weight and crucial body-protein stores (body cell mass), affects a person’s ability to survive HIV disease. With a loss of body cell mass to a level of 54% of the expected value based on height, death is likely to occur in HIV-infected patients, regardless of the presence or absence of infectious complications,” a further confirmation of nutrition’s role in treatment.

The situation is similar for patients with cancer, a population in which those who lose more than 10% of body weight have the worst prognosis. David Grotto, RD, LDN, a spokesperson for the ADA and former director of nutrition for a cancer center, says, “Weight makes such a difference in whether they [wasting patients] make it or not.” However, Blanco-Schumacher, who also specializes in working with underweight in cancer patients, notes that in instances involving wasting diseases, “There is a whole different mechanism to weight gain and should be approached as such.”

Grotto’s recommendation is to make certain situations a little lighter. A certified laughter leader, he says of patients who have just heard terrible or heavy news, “The last thing they want to hear about is nutrition.” He recommends a timely and appropriate joke, a smile, and “all the simple things that go together to make people happy.”

Over/Under Parallel
The parallel between overweight and underweight continues in treatment approaches. Successful weight gain comes down to the age-old tactic of pairing a structured diet with regular physical activity. Healthy weight gain, like healthy weight loss, requires guidance and determined effort. “The key,” Blanco-Schumacher says, “to gaining weight is to take in more calories than you burn.”

The first major step, Blanco-Schumacher says, is to find a healthy weight target and proceed from that starting point by upping the client’s caloric intake. She recommends an extra 500 to 1,000 calories per day, depending on the patient’s needs and goals. Much of the regimen should be based on the individual’s wants and needs, Blanco-Schumacher emphasizes. “It’s important to be comfortable and healthy. When people are underweight, they don’t look or feel their best.” Being proactive includes recognizing that it’s not unhealthy to be thinner than other people; it’s just of utmost importance to be as healthy as possible, she says.

As with weight loss, 1 to 2 pounds per week is a healthy target, says Blanco-Schumacher, when it comes to putting on weight. Similarly, realistic goals are also essential for proper weight gain, Grotto says. “Communication is critically important” when it comes to keeping a patient on target and hopeful, he says.

While communication is the crux, the key to successful weight gain, as with weight loss, is balance. A balanced diet in conjunction with a balanced exercise regimen is vital. Blanco-Schumacher suggests that workouts be centered on building lean muscle mass through weight training, starting lightly and increasing weight gradually. Many people view exercise as a means of weight loss, Grotto points out, which is why many find it surprising that weight gain relies equally on physical activity. “We know that lean tissue is an imperative,” Grotto says. To build and maintain that lean tissue, exercise is a must for underweight patients. “This is where [dietitians] can play a special role,” he says. “Find something that can be achieved and is fun.”

Grotto notes that there are some obstacles, especially for patients with wasting diseases. “They would love to gain weight, but in many cases they are physically challenged.” He acknowledges that with cancer patients, who often experience side effects such as fatigue, it will be a challenge to get them into “Arnold Schwarzenegger shape.” But there are always options. He recommends isometrics to put on lean muscle and resistance training with bands for patients who are bedridden or in a wheelchair. He also advises professionals to provide clients with at-home exercise options and limit anything that would require a gym membership. For patients who are too weak, conventional exercise may not be an immediate option. Instead, emphasize walking, climbing stairs with groceries, or other daily activities that serve the dual purpose of getting back into a normal routine and physical work.

A side benefit of an active lifestyle and regular workouts, Blanco-Schumacher notes, is increased appetite, which can start a positive cyclical effect.

Counting Calories and Making Them Count
Tipping the scales in a positive direction commences with choosing foods that are calorie dense but still beneficial. While fast food and bottomless desserts seem like a fantasy quick fix, emphasis should remain on foods that pack a nutritional punch through protein, vitamins, and minerals—not just empty calories from bad fats and processed sugars. Encourage clients to choose calorie-rich foods from each group of the Food Guide Pyramid, aiming for the higher end of the daily serving recommendations.

Incorporating extra calories into routine foods can often double the benefits. For example, Blanco-Schumacher suggests that clients switch to whole milk and add in dry milk powder, especially when preparing foods such as mashed potatoes, pudding, and shakes. Doing so, she says, helps patients add 210 calories as opposed to the 110 they would get from using skim or low-fat milk. Using milk in place of water in oatmeal, soups, and sides can add hundreds of calories more easily than switching to foods that clients may not be used to consuming. Powdered milk also adds protein and calcium in addition to extra calories. In the case of wasting diseases, Grotto, author of 101 Foods That Could Save Your Life, suggests that RDs “tailor a diet that behooves this patient population”—for example, fish oil and whey protein. He notes that fish oil in particular has recently been shown to help stimulate lean muscle and tissue growth. Alone, these dietary additions produce real results for patients, and “when coupled with physical activity, the results are tremendous.”

Snacking or grazing between meals and at bedtime also plays an important role in weight gain. Encourage smart snacks that add calories, vitamins, and minerals, such as nuts, dried fruits, and yogurt. But it’s also important to find nutritious foods that patients enjoy because they will gain zero benefits from something they refuse to eat. Blanco-Schumacher advises eating an energy-dense snack every two hours and implementing nutritional aids such as Ensure or Boost shakes. She also suggests implementing the aid of a food journal for patients to keep track of what they are consuming so they can stay on track for weight gain.

Remember, being able to eat anything without detectable consequences is deceptive—even people who are underweight need to be conscious about sugar and fat intake. Poor diets can lead to ailments such as heart disease, stroke, and cancer, regardless of body size or composition. Advise patients to enjoy meals with the right balance of proteins, carbohydrates, and healthy fats. Blanco-Schumacher suggests applying the ratio of 60% to 70% carbohydrates, 10% to 15% protein, and a healthy amount of fat.

In addition to proper diet and exercise, sometimes patients need pharmaceutical assistance. Appetite stimulants such as Megace and MARINOL may help patients gain weight. However, like many medications, they come with a price, having been shown to increase appetite but also increase fat, not muscle. Also, like many medicines, they have side effects.

— Meghan A.T.B. Reese is a freelance writer based in Boston.