Like many 23-year-olds, Amanda Eang is self-conscious about her body. She constantly covers up and wears loose-fitting clothing to disguise her shape.
At five-foot-two, she weighs just 93 pounds, and for years she has tried to gain weight.
"There are a lot of shows about losing weight, but they really don't have anything for people who are underweight," she says. "It's just as frustrating for people who are trying to gain weight."
Eang, who lives in Toronto, says she has tried everything: eating junk food (which left her with high cholesterol), drinking supplements and doing resistance training. She'd like to reach 110 pounds, but she has never even weighed 100 pounds.
Fewer than 2% of adults in the United States are underweight, according to 2007 to 2010 data collected by the National Center for Health Statistics. To be considered underweight, individuals must have a body mass index of less than 18.5. A woman who is five-foot-six, for example, would weigh 114 pounds or less.
For some, difficulty gaining weight can be a frustrating problem and must be approached in a healthy way, experts say.
Ruling out problems
Before attempting to put on pounds, individuals who feel they are underweight should visit their primary care doctor for a complete physical examination, says Craig Primack, a medical obesity specialist and member of the American Society of Bariatric Physicians.
A physician can rule out medical issues that would impede weight gain or cause malabsorption, including celiac disease, lactose intolerance, bacterial overgrowth syndrome or B12 deficiency.
Genetics play a big role in why some people are underweight, Primack says. A high metabolic rate is usually a factor, he says