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What is obesity the causes and simple diagnosis

Updated on November 3, 2016

What is Obesity and main Causes of Obesity

What is obesity? Diagnosis. in this hub you will find informations on what is Obesity and the main cause of this illness and hopefully understand and prevent from been effected by obesity. Obesity has been defined as an excess of body fat. This results in the problem of defining excess body fat since too little can also adversely affect health. how do i know if i have excess body fat? there are test that you can do to measure if your body has excessive fat. Nutritionists have devised a quantitative measurement – Body Mass Index [BMI]. what is Body mass index and how it is calculated? this is how body mass index works: BMI is body mass [kg] divided by the square of the height [metres] and is highly correlated with body fat. Importantly it does not correlate with height as tall and short people can be fat or thin. Although BMI is the best screening tool available it is not perfect. Height can be difficult to obtain in the elderly or injured. BMI is also confounded by anything that distorts weight measurements, e.g. oedema or ascites may account for many kg, whereas dehydration works the other way round. Very heavily muscled people may have a higher BMI. Those are some factors that your doctor or Nutritionists will have to take into account when measuring your body mass index

Range of BMI values: how to calculate bmi men and women.

bmi formula will tell you if you are normal , overweight obese or servery obese, below you will find the body mass index ranges for all stages of over weights this applies to women and man but as mention before there are other factors which should be taken into account

The normal range of a body mass index - if you are at range of 20 BMI TO 24.9 you are considered normal e.i not fat (Normal 20 – 24.9). if you mady mass index falls in this range than you know you are normal. you have a good weight.

overweight BMI 25 – 29.9, if your body mass index is in range than you are considered overweight. so you should start paying attention to what you eat so you don't become moderated obese which is the next range. if your body mass index is within this range you are considered overweight so you should start watching your diet and excises to go back to normal weight or at least prevent from going to the next stage which is moderately obese.

moderately obese body mass index range 30 – 34.9, this is a critical stage usually people that are at this range of body mass index are at a very high risk of becoming severely obese therefore a consultation with your doctor is a must to prevent severely obese and start on special diets so at least you can reduce your body mass index to 27 below levels watch out your in high risk of all the illnesses that come with obesity. you are in danger start doing something about your weight.

and the last two and most extremely critical stages of obesity start from a range of 35 BMI severely and morbidly obese you should always try to prevent yourself to getting to this stage by measuring your BMI regularly.

severely obese 35 –39.9, morbidly obese >40. these two stages are critical if your body mass index is within this range you really need to take this seriously.

What Causes Obesity

Causes of obesity. main reasons why people become obese

What are the causes of obesity what really causes it The principle cause is a disturbance of the homeostatic mechanisms that control energy balance but genetic endowment underlies this disturbance. Other factors such as food intake and lack of physical exercise contribute and there are important social, cultural and psychological aspects. For instance some individuals eat more during periods of heavy exercise or pregnancy and are unable to revert to their former eating habits. The increase in obesity in social class 5 can usually be related to the type of food consumed [ie food containing sugar and fat]. Psychological factors and how food is presented may overcome complex biochemical interactions. Also it has been shown that obese patients eat more than they admit to eating, and over the years a very small daily excess can lead to a large accumulation of fat e.g. 10.5kcal daily excess might be expected to lead to a 10kg weight gain over 20 years. Obesity is primarily an energy balance disorder, the details of which are not clear but may include the following:

  • Deficiencies in the genesis of, and/or the response to leptin or other fat depot sensors.
  • Defects in the hypothalamic neuronal systems responding to leptin or other fat depot sensors.
  • Defects in the systems controlling energy expenditure [eg reduced sympathetic activity].
  • Decreased metabolic expenditure of energy.
  • Decreased thermogenesis in adipocytes owing to dysfunction of the proteins that uncouple oxidative phosphorylation.

The tendency to develop obesity could reflect a genetic propensity, developed during evolution, to store fat at feasts for sustenance during famine that becomes disadvantageous in an environment associated with an overabundance of food.

Ghrelin is released from the stomach after fasting and increases food intake. NPY is a peptide neurotransmitter found in the hypothalamus whose release is decreased by leptin and insulin and increased by negative energy balance; it increases food intake and decreases energy expenditure. Leptin is released from white adipose tissue and its release is increased by glucocorticoids and insulin; it decreases food intake and increases energy expenditure, however, it should be noted that the regulation of satiety and hunger is extremely complex and people that are obese can exhibit resistance to the effects of leptin.

Energy balance depends on food intake, energy storage in fat, and energy expenditure. The homeostatic control of energy balance involves :

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Health Problems Caused by Obesity | Obesity

2. The relay of the information on state of fat stores to centres in the

hypothalamus [eg neurons with leptin receptors]. Some forms of damage

to the hypothalamus can cause uncontrollable eating behaviour [and weight gain].

The primary level of hypothalamic control is vested in two groups of neurons in the arcuate nucleus. They have opposing actions although both groups express leptin receptors. In one group, the peptides neuropeptide Y and agouti-related protein [AGRP] are co-localised, the other contains the protein prepro-opiomelanocortin [POMC], which releases α-melanocyte –stimulating hormone [α-MSH]. Activation of the first group by fall in leptin levels results in increased food intake and decreased energy expenditure. Increased leptin levels following overfeeding activates the second group and has the opposite effect. Insulin receptors also occur in both groups. Leptin and insulin act in concert on the hypothalamic neurons, but leptin is the main regulating factor.

Along with leptin, insulin has a critical role in energy homeostasis but many other factors also play a part eg. other endocrines, autonomic transmitters, other CNS neuropeptide transmitters and a variety of mediators released from adipose tissue [which is now regarded as an endocrine organ

1. Mechanisms that signal the level of fat stores eg leptin

Variations in

leptin concentration occur when there is increased food intake and/or

reduced energy expenditure; fat cells then increase in size and number

and their ob genes code for an increase in the basal levels of leptin

synthesis and release.

Treatment options for obesity

what to do if you are fat obese Treatment options for obesity

Primary aim to treat or prevent obesity is to reduce energy intake and increase energy expenditure.

Life style modification - includes diet [reduce saturated fat, increase fibre, increase fruit, decrease portion size], exercise [30min of moderately intense activity eg brisk walking, 5 days a week] and behavioural management [self-monitoring, realistic goal setting, stress management etc]

Pharmacological treatment - include drugs acting on gastrointestinal system and central nervous system. Orlistat is a pancreatic lipase inhibitor; steatorrhoea is a problem with this drug. Although the potential for such side-effects may help the patient reduce their fat intake. Sibutramine promotes a sense of satiety by acting as a noradrenaline /5-hydroxytryptamine reuptake inhibitor.

Somewhat surprisingly leptin was not found to be generally effective in reducing obesity. It is secreted from fat cells and was thought to act as a feedback mechanism between adipose tissue and the brain, acting as a „lipostat‟ or „adipostat„, controlling fat stores by regulating hunger and saiety. However it is now apparent that many other signals are involved.

Surgery – Gastric restriction and bypass and biliopancreatic diversion [taking the secretions into terminal ileum] are usually successful.

Complications and treatments of obesity

Complications of obesity and Treatments of Obesity

Lets start with the complications Metabolic syndrome

Obesity occurs as a result of a combination of genetic, environmental and psychological factors and is characterised by an imbalance in energy balance resulting from excessive food intake coupled with decreased energy expenditure. This imbalance interferes with energy homeostasis, a regulatory process involving hormones including insulin, ghrelin and leptin which circulate at levels in proportion to body fat content and act on the hypothalamus to influence food intake and fat stores. Obesity is closely associated with insulin resistance and, together with elevated serum triglyceride levels, low HDL and high LDL cholesterol levels, increased abdominal circumference [waist >102cm in males and >88cm in females] and elevated blood pressure [>130/85 mm Hg], produces a complex medical condition termed the METABOLIC SYNDROME and which is a component of cardiometabolic risk.


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    • Cogerson profile image

      Cogerson 5 years ago from Virginia

      Very interesting hub......lots of great information in this hub that is presented in a way that the information is useful....informative and educational....that is the mark of a good writer....great job...Voted up and very useful.

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