Underweight

Underweight is a term describing a human whose body weight is considered too low to be healthy. The definition usually refers to people with a body mass index (BMI) of under 18.5 or a weight 15% to 20% below that normal for their age and height group. BMI  is a key indicator of healthy weight. Although being lean can often be healthy, being underweight can be a concern if it's the result of poor nutrition or if you are pregnant or have other health concerns. So, if you're underweight, see your doctor or dietitian for an evaluation. Together, you can plan how to meet your goal weight.

Research studies show that underweight is deadlier than overweight. People who are clinically underweight face an even higher risk for dying than obese individuals, the study shows. Compared to normal-weight folks, the excessively thin have nearly twice the risk of death, researchers concluded after reviewing more than 50 prior studies.

Obesity has occupied center stage under the public health spotlight, but "we have [an] obligation to ensure that we avoid creating an epidemic of underweight adults and fetuses who are otherwise at the correct weight," said study leader Dr. Joel Ray, a physician-researcher at St. Michael's Hospital in Toronto.

Causes
A person may be underweight due to genetics, metabolism, lack of food (frequently due to poverty), or illness.

Being underweight is associated with certain medical conditions, including hyperthyroidism, cancer, or tuberculosis. People with gastrointestinal or liver problems may be unable to absorb nutrients adequately. People with anorexia nervosa become underweight due to self-starvation (often accompanied by excessive exercise).

Problems
Underweight might be secondary to or symptomatic of an underlying disease. Unexplained weight loss may require professional medical diagnosis.

Underweight can also be a primary causative condition. Severely underweight individuals may have poor physical stamina and a weak immune system, leaving them open to infection. According to Robert E. Black of the Johns Hopkins School of Public Health, "Underweight status ... and micronutrient deficiencies also cause decreases in immune and non-immune host defenses, and should be classified as underlying causes of death if followed by infectious diseases that are the terminal associated causes." People who are malnutrative underweight raise special concerns, as not only gross caloric intake may be inadequate, but also intake and absorption of other vital nutrients, especially essential amino acids and micro-nutrients such as vitamins and minerals.

In women, being grossly underweight can result in amenorrhea (absence of menstruation), infertility and possible complications during pregnancy. It can also cause anemia and hair loss.

Being underweight is an established risk factor for osteoporosis, even for young people. This is a particularly insidious consequence, because the affected persons do not notice the danger. After the occurrence of first spontaneous fractures the damage is often already irreversible.
Although being underweight has been reported to increase mortality at rates comparable to that seen in morbidly obese people, the effect is much less drastic when restricted to non-smokers with no history of disease, suggesting that smoking and disease-related weight loss are the leading causes of the observed effect.

Some healthy ways to gain weight when you're underweight:

DIET
Underweight individuals may be advised to gain weight by increasing calorie intake. This can be done by eating calorie-dense foods, such as dried fruits, cheese, and nuts.

Eat more frequently. When you're underweight, you may feel full faster. Eat five to six smaller meals during the day rather than two or three large meals.

Choose nutrient-rich foods. As part of an overall healthy diet, choose whole-grain breads, pastas and cereals; fruits and vegetables; dairy products; lean protein sources; and nuts and seeds.

Try smoothies and shakes. Don't fill up on diet soda, coffee and other drinks with few calories and little nutritional value. Instead, drink smoothies or healthy shakes made with milk and fresh or frozen juice, and sprinkle in some ground flaxseed. In some cases, a liquid meal replacement may be recommended.

Watch when you drink. Some people find that drinking fluids before meals blunts their appetite. In that case, it may be better to sip higher calorie beverages along with a meal or snack. For others, drinking 30 minutes after a meal, not with it, may work.

Make every bite count. Snack on nuts, peanut butter, cheese, dried fruits and avocados. Have a bedtime snack, such as a peanut butter and jelly sandwich, or a wrap sandwich with avocado, sliced vegetables, and lean meat or cheese.

Top it off. Add extras to your dishes for more calories — such as cheese in casseroles and scrambled eggs, and fat-free dried milk in soups and stews.

Have an occasional treat. Even when you're underweight, be mindful of excess sugar and fat. An occasional slice of pie with ice cream is OK. But most treats should be healthy and provide nutrients in addition to calories. Bran muffins, yogurt and granola bars are good choices.

Body weight may also be increased through the consumption of liquid nutritional supplements. Other nutritional supplements may be recommended for individuals with insufficient vitamin or mineral intake.

EXERCISE
Another way for underweight people to gain weight is by exercising. Muscle hypertrophy increases body mass. Weight lifting exercises are effective in helping to improve muscle tone as well as helping with weight gain. Weight lifting has also been shown to improve bone mineral density, for which underweight people have an increased risk of deficiency.
Exercise itself is catabolic, which results in a brief reduction in mass. The gain in weight that can result of it comes from the anabolic overcompensation when the body recovers and overcompensates via muscle hypertrophy. This can happen by an increase in the muscle proteins, or through enhanced storage of glycogen in muscles. Exercise can help stimulate a person's appetite if they are not inclined to eat.

APPETITE STIMULANTS
Certain drugs may increase appetite either as their primary effect or as a side effect. Antidepressants, such as mirtazapine or amitriptyline, and antipsychotics, particularly chlorpromazine and haloperidol as well as tetrahydrocannabinol (found in cannabis), all present an increase in appetite as a side effect. In states where it is approved, medicinal marijuana may be prescribed for severe appetite loss, such as that caused by cancer, AIDS, or severe levels of persistent anxiety. Other drugs which may increase appetite include certain benzodiazepines (such as diazepam), sedating antihistamines (such as diphenhydramine, promethazine or cyproheptadine, or B vitamin supplements.

The message yet again is to go calculate your BMI (Ref. Post on obesity for how to calculate your BMI) . God desires that we be in health. Stay healthy!