OBESITY



OBESITY

Obesity in absolute terms is an increase of body fatty tissue mass. In a practical setting it is difficult to measure this directly, and obesity is typically measured by BMI (body mass index) and in terms of its distribution through waist circumference or waist-hip circumference ratio measurements.[5] In addition, the presence of obesity needs to be evaluated in the context of other risk factors and comorbidities (other medical conditions that could influence risk of complications)


BMI

Body mass index or BMI is a simple and widely used method for estimating body fat mass. BMI was developed in the 19th century by the Belgian statistician and anthropometrist Adolphe Quetelet. BMI is an accurate reflection of body fat percentage in the majority of the adult population, but is less accurate in situations that affect body composition such as in body builders and pregnancy

BMI is calculated by dividing the subject's weight by the square of his/her height, typically expressed either in metric or US "Customary" units:

Metric: BMI = kg / m2

Where kg is the subject's weight in kilograms and m is the subject's height in metres.

US/Customary and imperial: BMI = lb * 703 / in2

Where lb is the subject's weight in pounds and in is the subject's height in inches


The most commonly used definitions, established by the WHO in 1997 and published in 2000, provide the following values:

  • A BMI less than 18.5 is underweight
  • A BMI of 18.5–24.9 is normal weight
  • A BMI of 25.0–29.9 is overweight
  • A BMI of 30.0–34.9 is class I obesity
  • A BMI of 35.0-39.9 is class II obesity
  • A BMI of > 40.0 is class III obesity or severe / morbidly obese
  • A BMI of 35.0 or higher in the presence of at least one other significant comorbidity is also classified by some bodies as morbid obesity.


Causes

Most researchers agree that a combination of excessive calorie consumption and a sedentary lifestyle are the primary causes of obesity in the majority of the population. Other less well established or minor influences include genetic causes, medical and psychiatric illnesses, and microbiological causes.

A 2006 review identifies ten other possibly under investigated causes for recently increasing rates of obesity:

(1) Insufficient sleep

(2) Endocrine disruptors - food substances that interfere with lipid metabolism,

(3) decreased variability in ambient temperature,

(4) decreased rates of smoking, which suppresses appetite,

(5) increased use of medication that leads to weight gain,

(6) Increased distribution of ethnic and age groups that tend to be heavier,

(7) Pregnancy at a later age,

(8) Intrauterine and intergenerational effects,

(9) Positive natural selection of people with a higher BMI,

(10) Assortative mating, heavier people tending to form relationships with each other.


Dietary

Despite the widespread availability of nutritional information in schools, doctors' offices, on the internet and on product packaging, it is evident that overeating remains a substantial problem. In the period of 1971-2000, obesity rates in the United States increased from 14.5% to 30.9% of the population. During the same time, an increase occurred in the average amount of calories consumed. For women, the average increase was 335 calories per day (1542 calories in 1971 and 1877 calories in 2004); while for men the average increase was 168 calories per day (2450 calories in 1971 and 2618 calories in 2004). Most of these extra calories came from an increase in carbohydrate consumption rather than an increase in fat consumption. Dietary trends have also change with reliance on energy-dense fast-food meals tripling between 1977 and 1995, and calorie intake from fast food quadrupling over the same period.


Sedentary lifestyle

An increasingly sedentary lifestyle plays a significant role in obesity. There has been a trend toward decreased physical activity due in part to increasingly mechanized forms of work, changing modes of transportation, and increasing urbanization. Studies in children and adults have found an association between the number of hours of television watched and the prevalence of obesity. Driving one's children to school also decreases the amount of exercise that these children get and has led to calls for reduced car use around schools. An association between leisure time activity and obesity has been found. For example in Canada, 27.0% of sedentary men are obese as opposed to 19.6% of active men.


Genetics

Like many other medical conditions, obesity is the result of interplay between genetic and environmental factors. Polymorphisms in various genes controlling appetite, metabolism, and adipokine release may predispose to obesity when sufficient calories are present. Obesity is a major feature in a number of rare genetic conditions: Prader-Willi syndrome, Bardet-Biedl syndrome, MOMO syndrome, leptin receptor mutations, and melanocortin receptor mutations. In a people with early-onset severe obesity (defined by an onset before ten years of age and body mass index over three standard deviations above normal), 7% harbour a single locus mutation. Apart from the above syndromes, an association has been found between an FTO gene polymorphism and weight. The 16% of adults in the study who were homozygous for this allele weighed about 3 kilograms more then those who had not inherited this trait and subsequently had a 1.6 fold greater rate of obesity. A study of 5092 identical twin found that childhood obesity has a strong (77%) inherited component, suggesting that many genetic influences underpinning the development of obesity are yet to be discovered.

On a population level, the thrifty gene hypothesis postulates that certain ethnic groups may be more prone to obesity when exposed to an equivalent environment. Their ability to take advantage of rare periods of abundance by storing energy as fat would be advantageous during times of varying food availability. Individuals with greater adipose reserves would be more likely survive famine. This tendency to store fat however would be maladaptive in societies with stable food supplies.


Medical illness

Certain physical and mental illnesses and the pharmaceutical substances used to treat them can increase one's risk of obesity. Medical illnesses that increase obesity risk include several rare genetic syndromes (listed above) as well as some congenital or acquired conditions: (1) hypothyroidism, (2) Cushing's syndrome, (3) growth hormone deficiency, and (4) eating disorders such bulimia nervosa, binge eating disorder and compulsive overeating.

Certain medications may cause weight gain and or negative changes in body composition, such as steroids, atypical antipsychotics, some fertility medication, insulin and sulfonylureas.


Microbiological

The role of bacteria colonizing the digestive tract in the development of obesity has recently become the subject of investigation. Bacteria participate in digestion (especially of fatty acids and polysaccharides), and alterations in the proportion of particular strains of bacteria may explain why certain people are more prone to weight gain than others. Human digestive tract bacteria are generally either member of the phyla of bacteroidetes or of firmicutes. In obese people, there is a relative abundance of firmicutes (which cause relatively high energy absorption), which is restored by weight loss. From these results it cannot be concluded whether this imbalance is the cause or effect of obesity.


Social determinants

The correlation between social class and BMI is inconsistent. Comparing net worth with BMI found obese Americanians approximately half as wealthy as thin ones. When income differentials were factored out, the inequity persisted. A tendency to rely on fast food is seen as one of the reasons why this result occurred. Another study found women who married into a higher social class are thinner than women who married into a lower social class. The 2004 Canadian Health Survey however found the exact opposite. It found that men from lower middle income households were less likely to be obese than were those in the highest income households and women from middle income households had the highest rates of obesity.


Treatment

Homoeopathic system of medicine have very effective medicines for obesity, regular intake of medicine is very much helpful to control and reduce the weight with out produce any side effect


For homoeopathic treatment

Please click the following link


http://treatmentt.blogspot.com/2009/12/obesity-treatment.html





Thursday, July 21, 2011

Food additive





Food additive
Some claim that food additives, such as artificial sweeteners, colorants, preserving agents, and flavourings may cause health problems such as increasing the risk of cancer or ADHD.

Junk food
  • That is unhealthy and/or has little or no nutritional value. The term is believed to have been coined by Michael Jacobson, director of the Centre for Science in the Public Interest, in 1972. The term has since come into common usage.
  • Junk food contains high levels of refined sugar, white flour, trans fat and polyunsaturated fat, salt, and numerous food additives such as monosodium glutamate and tartrazine; at the same time, it is lacking in proteins, vitamins and fibre, among other healthy attributes. It is popular with suppliers because it is relatively cheap to manufacture, has a long shelf life and may not require refrigeration. It is popular with American consumers, as well as other consumers from all over the world, because it is easy to purchase, requires little or no preparation, is convenient to consume and has lots of flavour. Consumption of junk food in America has been associated with obesity, heart disease, Type 2 diabetes and dental cavities. There is also concern about the targeting of marketing to children.

Classification
What constitutes unhealthy food may be confusing and, according to critics, includes elements of class snobbery, cultural influence and moral judgement. For example, fast food in North America, such as as hamburgers and French fries supplied by companies like McDonald's, KFC and Pizza Hut, are often perceived as junk food, whereas the same meals supplied by more up-market outlets such as California Pizza Kitchen or Nando's are not, despite often having the same or worse nutritional content. Some foods that are considered ethnic or traditional are not generally considered junk food, such as falafel, gyro, pakora, gyoza or chicharron, though all of these foods have little nutritional value and are usually high in fat from being fried in oil. Other foods such as white rice or roast potatoes are not considered junk food despite having limited nutritional content compared to wholegrain foods. Similarly, breakfast cereals are often regarded as healthy but may have high levels of sugar, salt and fat.

Hostess Twinkies
  • Some types of chips that are said to be "junk food" may actually be partially harmful because they may contain polyunsaturated and monounsaturated fats. It should also be understood that the detrimental effects of the empty calories may outweigh the benefits of the unsaturated fats. These foods tend to be high in sodium, which may contribute in causing hypertension (high blood pressure) in people sensitive to its effects with an existing electrolyte imbalance or inability to excrete sodium properly.
  • In the United Kingdom, the Food Standards Agency (FSA) do not use the term "junk food", and describe food as "HFSS" (high fat, sugar or salt) instead, based on a nutrient profiling model[3]. They state that "HFSS foods can form part of a balanced diet, but research shows that children's diets contain too much fat (especially saturated fat), salt and sugar, and not enough fruit and vegetables."
  • Eating a poor diet when pregnant or breastfeeding may cause long-lasting health damage, 







1 comment:

Kojen said...

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