Underweight
Encyclopedia
The term underweight refers to a human
who is considered to be under a healthy weight
. "Underweight" means weighing less than what is expected to be a healthy person (underweight = insufficiency of weight). The definition is usually made with reference to the body mass index
(BMI). A BMI of under 18.5 is usually referred to as underweight. This medical definition of underweight may differ from other uses of the term, such as those based on attractiveness
.
caused by the unavailability of adequate food. The effects of primary malnutrition may be amplified by disease; even easily treatable diseases such as diarrhea may lead to death.
Some people are underweight due to genetics
; others due to poverty.
Being underweight can sometimes be the result of mental or physical disease, such as hyperthyroidism
, cancer
, or tuberculosis
. People with gastrointestinal or liver problems may be unable to absorb nutrients adequately. People with eating disorders are likely to become underweight, such as anorexia nervosa
.
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.
Underweight is an established risk factor for osteoporosis
, even for young people. This is a particular insidious consequence, because the affected persons do not notice the danger. After the occurrence of first spontaneous fractures the damage is often already irreversible.
Being underweight causes increased mortality at rates comparable to that seen in morbidly obese people.
and not getting adequate exercise. The healthy way to gain weight is by increasing calorie amounts of the food that you already eat. Placing reasonable amounts of butter
, cream
or cheese
sauce
s, peanut butter
, olive oil
, salad dressing, seeds
, and nuts
on foods help increase food calories. Eating calorie-dense foods can also be beneficial. Some examples of calorie-dense foods are: dried fruits, cheese
, raisin
s, and nuts
. Drinking liquids with high calories can add up weight. Some examples of popular weight gain drinks are Ensure
and Boost
. Other examples are milk
and fruit juice. Eating a healthy diet is also crucial in weight gain. Consuming starchy vegetables like potato
es and corn
can also add weight gain. Eating protein
, healthy fats
, carbohydrates, vegetables, fruits are important for a weight gain diet. Nutritional supplements may be beneficial for people who aren't getting enough vitamins or minerals.
or amitryptiline, 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 even severe levels of persistent anxiety
. Other drugs which may increase appetite include certain benzodiazepines (such as diazepam
), sedating antihistamines (such as diphenhydramine
or promethazine
, or B vitamin supplements.
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 over-compensation when the body recovers (via rest and eating) and overcompensates via muscle hypertrophy
. This can happen via an increase in the muscle proteins, or through enhanced storage of glycogen
in muscles. Exercise can help stimulate people's appetite if they are not inclined to eat.
Human
Humans are the only living species in the Homo genus...
who is considered to be under a healthy weight
Weight
In science and engineering, the weight of an object is the force on the object due to gravity. Its magnitude , often denoted by an italic letter W, is the product of the mass m of the object and the magnitude of the local gravitational acceleration g; thus:...
. "Underweight" means weighing less than what is expected to be a healthy person (underweight = insufficiency of weight). The definition is usually made with reference to the body mass index
Body mass index
The body mass index , or Quetelet index, is a heuristic proxy for human body fat based on an individual's weight and height. BMI does not actually measure the percentage of body fat. It was invented between 1830 and 1850 by the Belgian polymath Adolphe Quetelet during the course of developing...
(BMI). A BMI of under 18.5 is usually referred to as underweight. This medical definition of underweight may differ from other uses of the term, such as those based on attractiveness
Attractiveness
Attractiveness or attraction refers to a quality that causes an interest or desire in something or someone. The term attraction may also refer to the object of the attraction itself, as in tourist attraction.-Visual attractiveness:...
.
Causes
The most common cause of a person being underweight is primarily malnutritionMalnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....
caused by the unavailability of adequate food. The effects of primary malnutrition may be amplified by disease; even easily treatable diseases such as diarrhea may lead to death.
Some people are underweight due to genetics
Genetics
Genetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
; others due to poverty.
Being underweight can sometimes be the result of mental or physical disease, such as hyperthyroidism
Hyperthyroidism
Hyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
, cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, or tuberculosis
Tuberculosis
Tuberculosis, MTB, or TB is a common, and in many cases lethal, infectious disease caused by various strains of mycobacteria, usually Mycobacterium tuberculosis. Tuberculosis usually attacks the lungs but can also affect other parts of the body...
. People with gastrointestinal or liver problems may be unable to absorb nutrients adequately. People with eating disorders are likely to become underweight, such as anorexia nervosa
Anorexia nervosa
Anorexia nervosa is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. Although commonly called "anorexia", that term on its own denotes any symptomatic loss of appetite and is not strictly accurate...
.
Problems
The immediate problem with being underweight is that it might be secondary to, and/or symptomatic of, an underlying disease. Unexplained weight loss requires professional medical diagnosis.Underweight can also be a primary causative condition. Severely underweight individuals may have poor physical stamina and a weak immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
, leaving them open to infection
Infection
An infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
. 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
Pregnancy
Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...
. It can also cause anemia and hair loss.
Underweight is an established risk factor for osteoporosis
Osteoporosis
Osteoporosis is a disease of bones that leads to an increased risk of fracture. In osteoporosis the bone mineral density is reduced, bone microarchitecture is deteriorating, and the amount and variety of proteins in bone is altered...
, even for young people. This is a particular insidious consequence, because the affected persons do not notice the danger. After the occurrence of first spontaneous fractures the damage is often already irreversible.
Being underweight causes increased mortality at rates comparable to that seen in morbidly obese people.
Diet
There are two ways to gain weight - an unhealthy way and a healthy way. The unhealthy route to gaining weight is consuming junk foodJunk food
Junk food is an informal term applied to some foods that are perceived to have little or no nutritional value ; to products with nutritional value, but which also have ingredients considered unhealthy when regularly eaten; or to those considered unhealthy to consume at all...
and not getting adequate exercise. The healthy way to gain weight is by increasing calorie amounts of the food that you already eat. Placing reasonable amounts of butter
Butter
Butter is a dairy product made by churning fresh or fermented cream or milk. It is generally used as a spread and a condiment, as well as in cooking applications, such as baking, sauce making, and pan frying...
, cream
Cream
Cream is a dairy product that is composed of the higher-butterfat layer skimmed from the top of milk before homogenization. In un-homogenized milk, over time, the lighter fat rises to the top. In the industrial production of cream this process is accelerated by using centrifuges called "separators"...
or cheese
Cheese
Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....
sauce
Sauce
In cooking, a sauce is liquid, creaming or semi-solid food served on or used in preparing other foods. Sauces are not normally consumed by themselves; they add flavor, moisture, and visual appeal to another dish. Sauce is a French word taken from the Latin salsus, meaning salted...
s, peanut butter
Peanut butter
Peanut butter is a food paste made primarily from ground dry roasted peanuts, popular in North America, Netherlands, United Kingdom, and parts of Asia, particularly the Philippines and Indonesia. It is mainly used as a sandwich spread, sometimes in combination as in the peanut butter and jelly...
, olive oil
Olive oil
Olive oil is an oil obtained from the olive , a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps...
, salad dressing, seeds
SEEDS
SEEDS is a voluntary organisation registered under the Societies Act of India....
, and nuts
Nut (fruit)
A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...
on foods help increase food calories. Eating calorie-dense foods can also be beneficial. Some examples of calorie-dense foods are: dried fruits, cheese
Cheese
Cheese is a generic term for a diverse group of milk-based food products. Cheese is produced throughout the world in wide-ranging flavors, textures, and forms....
, raisin
Raisin
Raisins are dried grapes. They are produced in many regions of the world. Raisins may be eaten raw or used in cooking, baking and brewing...
s, and nuts
Nut (fruit)
A nut is a hard-shelled fruit of some plants having an indehiscent seed. While a wide variety of dried seeds and fruits are called nuts in English, only a certain number of them are considered by biologists to be true nuts...
. Drinking liquids with high calories can add up weight. Some examples of popular weight gain drinks are Ensure
Ensure
Ensure is the brand name of a family of liquid nutritional supplements manufactured by Abbott Laboratories.The beverages are meant to be administered orally, or through nasogastric tubes, directly to the recipient's stomach....
and Boost
Boost
-Science, technology and mathematics:* Automotive:** Boost, positive manifold pressure in cars, see Turbocharger#Pressure increase.*** a loose term for turbo or supercharger** A slang term meaning to start a vehicle, see jump start...
. Other examples are milk
Milk
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
and fruit juice. Eating a healthy diet is also crucial in weight gain. Consuming starchy vegetables like potato
Potato
The potato is a starchy, tuberous crop from the perennial Solanum tuberosum of the Solanaceae family . The word potato may refer to the plant itself as well as the edible tuber. In the region of the Andes, there are some other closely related cultivated potato species...
es and corn
Corn
Corn is the name used in the United States, Canada, and Australia for the grain maize.In much of the English-speaking world, the term "corn" is a generic term for cereal crops, such as* Barley* Oats* Wheat* Rye- Places :...
can also add weight gain. Eating protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
, healthy fats
Fats
Fats may refer to:*Fat, a generic term for a class of lipids in biochemistry*Fats Domino, rock and roll pianist*Fats Waller, jazz pianist*Fats Navarro, jazz trumpeter*Singing Fats, master of ceremonies*Obesity...
, carbohydrates, vegetables, fruits are important for a weight gain diet. Nutritional supplements may be beneficial for people who aren't getting enough vitamins or minerals.
Exercise
Another way for underweight people to gain weight is by exercising to obtain muscle mass. The addition of muscles will increase your body mass. Weight-lifting exercises are effective in helping to increase muscle tone and gain weight.Appetite Stimulants
Finally, certain drugs may increase appetite either as their primary effect, or as a side-effect as in the majority of cases. Antidepressants such as mirtazapineMirtazapine
Mirtazapine is a tetracyclic antidepressant used primarily in the treatment of depression. It is also sometimes used as a hypnotic, antiemetic, and appetite stimulant, and for the treatment of anxiety, among other indications...
or amitryptiline, antipsychotics (particularly chlorpromazine
Chlorpromazine
Chlorpromazine is a typical antipsychotic...
and haloperidol
Haloperidol
Haloperidol is a typical antipsychotic. It is in the butyrophenone class of antipsychotic medications and has pharmacological effects similar to the phenothiazines....
, as well as tetrahydrocannabinol
Tetrahydrocannabinol
Tetrahydrocannabinol , also known as delta-9-tetrahydrocannabinol , Δ1-THC , or dronabinol, is the main chemical psychoactive substance found in the cannabis plant. It was first isolated in 1964. In pure form, it is a glassy solid when cold, and becomes viscous and sticky if warmed...
(found in cannabis
Cannabis
Cannabis is a genus of flowering plants that includes three putative species, Cannabis sativa, Cannabis indica, and Cannabis ruderalis. These three taxa are indigenous to Central Asia, and South Asia. Cannabis has long been used for fibre , for seed and seed oils, for medicinal purposes, and as a...
), 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
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
, AIDS
AIDS
Acquired immune deficiency syndrome or acquired immunodeficiency syndrome is a disease of the human immune system caused by the human immunodeficiency virus...
or even severe levels of persistent anxiety
Anxiety
Anxiety is a psychological and physiological state characterized by somatic, emotional, cognitive, and behavioral components. The root meaning of the word anxiety is 'to vex or trouble'; in either presence or absence of psychological stress, anxiety can create feelings of fear, worry, uneasiness,...
. Other drugs which may increase appetite include certain benzodiazepines (such as diazepam
Diazepam
Diazepam , first marketed as Valium by Hoffmann-La Roche is a benzodiazepine drug. Diazepam is also marketed in Australia as Antenex. It is commonly used for treating anxiety, insomnia, seizures including status epilepticus, muscle spasms , restless legs syndrome, alcohol withdrawal,...
), sedating antihistamines (such as diphenhydramine
Diphenhydramine
Diphenhydramine hydrochloride is a first-generation antihistamine possessing anticholinergic, antitussive, antiemetic, and sedative properties which is mainly used to treat allergies. Like most other first-generation antihistamines, the drug also has a powerful hypnotic effect, and for this reason...
or promethazine
Promethazine
Promethazine is a first-generation antihistamine of the phenothiazine family. The drug has anti-motion sickness, antiemetic, and anticholinergic effects, as well as a strong sedative effect and in some countries is prescribed for insomnia when benzodiazepines are contraindicated...
, or B vitamin supplements.
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 over-compensation when the body recovers (via rest and eating) and overcompensates via muscle hypertrophy
Hypertrophy
Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It should be distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number...
. This can happen via an increase in the muscle proteins, or through enhanced storage of glycogen
Glycogen
Glycogen is a molecule that serves as the secondary long-term energy storage in animal and fungal cells, with the primary energy stores being held in adipose tissue...
in muscles. Exercise can help stimulate people's appetite if they are not inclined to eat.