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Hunger

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This article is about hunger as a motivational state. For other uses, see Hunger (disambiguation).
"Hungry" redirects here. For other uses, see Hungry (disambiguation).


Hunger is a feeling experienced when one has a desire to eat. The often unpleasant feeling originates in the hypothalamus and is released through receptors in the liver. Although an average nourished individual can survive weeks without food intake,[1] the sensation of hunger typically begins after a couple of hours without eating and is generally considered quite uncomfortable. The sensation of hunger can often be alleviated and even mitigated entirely with the consumption of food. Hunger is also the most commonly used term to describe the social condition of people who frequently experience, or live with the threat of experiencing, the physical sensation of hunger. (See also: Malnutrition)

Hunger pangs

When hunger contractions start to occur in the stomach, these are commonly referred to as hunger pangs. Hunger pangs usually do not begin until 12 to 24 hours after the last ingestion of food. A single hunger contraction lasts about 30 seconds, and pangs continue for around 30–45 minutes, then hunger subsides for around 30-150 minutes.[2] Individual contractions are separated at first, but are almost continuous after a certain amount of time.[2] Emotional states (anger, joy etc.) may inhibit hunger contractions.[2] Levels of hunger are increased by lower blood sugar levels, and are higher in diabetics.[2] They reach their greatest intensity in 3 to 4 days and may weaken in the succeeding days, though hunger never disappears.[3] Hunger contractions are most intense in young, healthy people who have high degrees of gastrointestinal tonus. Periods between contractions increase with old age.[2]

Biological mechanisms

The fluctuation of leptin and ghrelin hormone levels results in the motivation of an organism to consume food. When an organism eats, adipocytes trigger the release of leptin into the body. Increasing levels of leptin results in a reduction of one's motivation to eat.[4] After hours of non-consumption, leptin levels drop significantly. These low levels of leptin cause the release of secondary hormone, ghrelin, which in turn reinitiates the feeling of hunger.

Some studies have suggested that an increased production of ghrelin may enhance appetite evoked by the sight of food, while an increase in stress may also influence the hormone's production.[5] These findings may help to explain why hunger can prevail even in stressful situations.

Behavioral response

Hunger appears to increase activity and movement in many animals - for example, an experiment on spiders showed increased activity and predation in starved spiders, resulting in larger weight gain.[6] This pattern is seen in many animals, including humans while sleeping.[7] It even occurs in rats with their cerebral cortex or stomachs completely removed.[8] Increased activity on hamster wheels occurred when rats were deprived not only of food, but also water or B vitamins such as thiamine[9] This response may increase the animal's chance of finding food, though it has also been speculated the reaction relieves pressure on the home population.[7]

Hunger statistics

Main article: Malnutrition

There were 923 million hungry people in the world in 2007, an increase of 80 million since 1990.[10] The world already produces enough food to feed everyone - 6 billion people - and could feed the double - 12 billion people.[11]

Hunger in the United States

The Meals On Wheels Association of America Foundation (MOWAAF) has found that hunger is a serious threat facing millions of seniors in the United States, and that understanding the problem is a critical first step to developing remedies. In 2007, MOWAAF, underwritten by the Harrah's Foundation, commissioned a research study entitled The Causes, Consequences and Future of Senior Hunger in America.[12] The report was released at a hearing of the U.S. Senate Special Committee on Aging in March 2008 in Washington, D.C.

The study found that in the United States, over 5 million seniors, (11.4% of all seniors), experience some form of food insecurity (i.e., were marginally food insecure). Of these, about 2.5 million are at-risk of hunger, and about 750,000 suffer from hunger due to financial constraints. Some groups of seniors are more likely to be at-risk of hunger. Relative to their representation in the overall senior population, those with limited incomes, under age 70, African-Americans, Hispanics, never-married individuals, renters, and persons living in the Southern United States are all more likely to be at-risk of hunger. While certain groups of seniors are at greater-risk of hunger, hunger cuts across the income spectrum. For example, over 50% of all seniors who are at-risk of hunger have incomes above the poverty threshold. Likewise, it is present in all demographic groups. For example, over two-thirds of seniors at-risk of hunger are caucasian. There are marked differences in the risk of hunger across family structure, especially for those seniors living alone, or those living with a grandchild. Those living alone are twice as likely to experience hunger compared to married seniors. One in five senior households with a grandchild (but no adult child) present is at-risk of hunger, compared to about one in twenty households without a grandchild present. Seniors living in non-metropolitan areas are as likely to experience food insecurity as those living in metropolitan areas, suggesting that food insecurity cuts across the urban-rural continuum.[13]

Year 1970 1980 1990 2005 2007
Share of hungry people in the developing world[14][15] 37 % 28 % 20 % 16 % 17 %

Hunger mortality statistics

  • On the average, a person dies every second as a result of starvation - 4,000 every hour - 100,000 each day - 36 million each year - 58% of all deaths (2001-2004 estimates).[16][17][18]
  • On the average, a child under five dies every 5 seconds as a result of starvation - 700 every hour - 16,000 each day - 6 million each year - 60% of all child deaths (2002-2008 estimates).[19][20][21][22][23]

See also

Wikiversity has learning resources about Hunger

Organizations

References

  1. ^ "How long can someone survive without water?". Retrieved 2007-05-14.
  2. ^ a b c d e A. J. Carlson (1931) Hunger The Scientific Monthly 33:77-79.
  3. ^ Carlson, A. J. & Hoelzel, F. (1952). The alleged disappearance of hunger during starvation. Science, 115:526-527.
  4. ^ OMIM - LEPTIN; LEP
  5. ^ Malik, S (2007). Cell Metabolism. 7: 400–9. PMID 18460331. {{cite journal}}: Missing or empty |title= (help); Unknown parameter |coauthors= ignored (|author= suggested) (help)
  6. ^ Provencher, L. & Riechert, S. E. (1991) Short-Term Effects of Hunger Conditioning on Spider Behavior, Predation, and Gain of Weight Oikos 62:160-166
  7. ^ a b Wald, G.; Jackson, B. (1944) Activity and Nutritional Deprivation Proceedings of the National Academy of Sciences of the United States of America 30:255-263
  8. ^ "George Wald: The Origin of Death". Retrieved 2007-05-14.
  9. ^ Guerrant, N.B., Dutcher, R.A. (1940) Journal of Nutrition 20:589.
  10. ^ Food and Agriculture Organization Economic and Social Development Department. “The State of Food Insecurity in the World, 2008 : High food prices and food security - threats and opportunities”. Food and Agriculture Organization of the United Nations, 2008, p. 2. “FAO’s most recent estimates put the number of hungry people at 923 million in 2007, an increase of more than 80 million since the 1990–92 base period.”.
  11. ^ Jean Ziegler. “Promotion And Protection Of All Human Rights, Civil, Political, Economic, Social And Cultural Rights, Including The Right To Development: Report of the Special Rapporteur on the right to food, Jean Ziegler”. Human Rights Council of the United Nations, January10, 2008.“According to the Food and Agriculture Organization of the United Nations (FAO), the world already produces enough food to feed every child, woman and man and could feed 12 billion people, or double the current world population.”
  12. ^ Ziliak, Gundersen and Haist. (2007) The Causes, Consequences and Future of Senior Hunger in America, University of Kentucky Center for Poverty and Research, Lexington, KY. (88pages. 2MB.)
  13. ^ Excerpt from "The Causes, Consequences and Future of Senior Hunger in America", Executive Summary, pp.i-ii
  14. ^ Food and Agriculture Organization Agricultural and Development Economics Division. “The State of Food Insecurity in the World, 2006 : Eradicating world hunger – taking stock ten years after the World Food Summit”. Food and Agriculture Organization of the United Nations, 2006, p. 8. “Because of population growth, the very small decrease in the number of hungry people has nevertheless resulted in a reduction in the proportion of undernourished people in the developing countries by 3 percentage points – from 20 percent in 1990–92 to 17 percent in 2001–03. (…) the prevalence of undernourishment declined by 9 percent (from 37 percent to 28 percent) between 1969–71 and 1979–81 and by a further 8 percentage points (to 20 percent) between 1979–81 and 1990–92.”.
  15. ^ Food and Agriculture Organization Economic and Social Development Department. “The State of Food Insecurity in the World, 2008 : High food prices and food security - threats and opportunities”. Food and Agriculture Organization of the United Nations, 2008, p. 6. “Good progress in reducing the share of hungry people in the developing world had been achieved – down from almost 20 percent in 1990–92 to less than 18 percent in 1995–97 and just above 16 percent in 2003–05. The estimates show that rising food prices have thrown that progress into reverse, with the proportion of undernourished people worldwide moving back towards 17 percent.”.
  16. ^ Jean Ziegler. “The Right to Food: Report by the Special Rapporteur on the Right to Food, Mr. Jean Ziegler, Submitted in Accordance with Commission on Human Rights Resolution 2000/10”. United Nations, February 7, 2001, p. 5. “On average, 62 million people die each year, of whom probably 36 million (58 per cent) directly or indirectly as a result of nutritional deficiencies, infections, epidemics or diseases which attack the body when its resistance and immunity have been weakened by undernourishment and hunger.”.
  17. ^ Commission on Human Rights. “The right to food : Commission on Human Rights resolution 2002/25”. Office Of The High Commissioner For Human Rights, United Nations, April 22, 2002, p. 2. “every year 36 million people die, directly or indirectly, as a result of hunger and nutritional deficiencies, most of them women and children, particularly in developing countries, in a world that already produces enough food to feed the whole global population”.
  18. ^ United Nations Information Service. “Independent Expert On Effects Of Structural Adjustment, Special Rapporteur On Right To Food Present Reports: Commission Continues General Debate On Economic, Social And Cultural Rights”. United Nations, March 29, 2004, p. 6. “Around 36 million people died from hunger directly or indirectly every year.”.
  19. ^ Food and Agriculture Organization Staff. “The State of Food Insecurity in the World, 2002: Food Insecurity : when People Live with Hunger and Fear Starvation”. Food and Agriculture Organization of the United Nations, 2002, p. 6. “6 million children under the age of five, die each year as a result of hunger.”
  20. ^ Food and Agriculture Organization of the United Nations Economic and Social Dept. “The State of Food Insecurity in the World 2004: Monitoring Progress Towards the World Food Summit and Millennium Development Goals”. Food and Agriculture Organization of the United Nations, 2004, p. 8. “Undernourishment and deficiencies in essential vitamins and minerals cost more than 5 million children their lives every year”.
  21. ^ Jacques Diouf. “The State of Food Insecurity in the World 2004: Monitoring Progress Towards the World Food Summit and Millennium Development Goals”. Food and Agriculture Organization of the United Nations, 2004, p. 4. “one child dies every five seconds as a result of hunger and malnutrition”.
  22. ^ Food and Agriculture Organization, Economic and Social Dept. “The State of Food Insecurity in the World 2005: Eradicating World Hunger - Key to Achieving the Millennium Development Goals”. Food and Agriculture Organization of the United Nations, 2005, p. 18. “Hunger and malnutrition are the underlying cause of more than half of all child deaths, killing nearly 6 million children each year – a figure that is roughly equivalent to the entire preschool population of Japan. Relatively few of these children die of starvation. The vast majority are killed by neonatal disorders and a handful of treatable infectious diseases, including diarrhoea, pneumonia, malaria and measles. Most would not die if their bodies and immune systems had not been weakened by hunger and malnutrition moderately to severely underweight, the risk of death is five to eight times higher.”.
  23. ^ Human Rights Council. “Resolution 7/14. The right to food”. United Nations, March 27, 2008, p. 3. “6 million children still die every year from hunger-related illness before their fifth birthday”.

External links

Wikimedia Commons has media related to Hunger.
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