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From Mediwikis

Obesity can be defined socially or medically. Socially is societies opinion of what is healthy, and medically it is a Body Mass Index over 30 kg/m2 .

Associated Facts

Women are at a higher risk than men of developing diabetes due to their gynoid shape (man are android – belly only fat).

Visceral fat (located around organs) is the worst type of fat, and is linked to type 2 diabetes, insulin resistance, inflammatory diseases, and other obesity-related diseases.

Obesity in children can lead to obesity in adulthood[1].

Complications of Obesity

Energy Requirements

  • ~10% of our energy is burned off as heat immediately when eating
  • ~10% of our energy is burned off by fidgeting
  • 1.5 kg of glycogen in the liver stored
  • Protein and Carbohydrates are regulated by our bodies
  • Fat is not regulated
  • The more someone weighs the higher their fat percentage(usually)

Control Mechanisms

Overeating = more dietary thermogenesis

Under-eating = less thermogenesis and fidgeting

Causes of obesity

  • Genetics 10%
  • Glandular 1%
  • Brain injuries ~9%
  • Environment and Genetics >80%

Social causes

  • Poverty
  • Fast Food
  • Carbonated Drinks (empty calories)
  • Television
  • Central Heating


  • Surgery (most effective)
  • Medication
  • Diet
  • Lifestyle
  • Exercise

Types of surgery

Stomach bypass – deficiency risks

Stomach band – reduces appetite hormones secretion

Smaller stomach - reduces digestion, thus absorption.


  • Appetite suppressants – many side affects
  • Lipase inhibitors such as orlistat and sibutramine reduce body weight and blood pressure[2]


Lean tissue ratio needs to be preserved, however proteins are usually broken down after a couple days

Need support

Activity needed


Not effective for weight loss, unless lean mass increased (increase MR)

Improves cardiac output

Reduces risk of type 2 diabetes

Works better for men

Example- 10kg weight loss

Results in:

  • ~20% reduction in death
  • ~30% reduction in diabetes occurrences
  • ~40% reduction in obesity linked cancers

as well as a lower BP, better lipid profile, improved fertility and better respiration.

Control of eating

Remember thirst is more powerful than hunger.

Three stages Hunger, Eating, Stop Eating.

Natural state is to eat, thus control is essentially inhibition of the desire to eat and eating.

Your body knows exactly how much fat and energy is has (lipo/ergo-stat)

Appetite arises from the “Arcuate Nuclei” which are just neurone colonies in the hypothalamus.


Insulin and Leptin

Both suppress appetite, though leptin is not as potent.

Leptin deficiency is a major problem and can cause obesity[3].

Leptin is a adipose cell hormone thus the more you have the more fat you have, it is important for fertility and puberty.

Insulin is released when blood sugar is high.


Grehlin is the "hunger hormone" which is produced when the stomach is relaxed (empty). Secretion is stopped when the stomach is stretched. Ghrelin is a neuropeptide, thus acts directly on the brain to create appetite.

Peptide YY

A hormone produce mainly in the ileum and colon, due to protein and food presence thus suppresses hunger.

Hungry Behaviour

  • Hunger pains
  • Obsession
  • Salivation and gastric activity
  • foraging

Stopping oneself from consuming food - Satiation

  • Experience
  • Limits (diets)
  • Gut hormones (PYY, Leptin)
  • Stomach distension (Lack of Ghrelin)
  • Nutrient absorption (Blood sugar)

Types of Eating Problems

Drug related satiation

  • Opiates (-)
  • Alcohol (+)
  • Valporate (+)
  • Nicotine (-)
  • THC (+)


Pre-preganacy weight determines pregnancy changes.

Obese before requires more food during pregnancy

Underweight before require less food for the same weight at pregnancy

Prader Willi Syndrome

A rare disorder (1:25000) where by the person inherits dysfunctional genes on the paternal chromosome 15- inheritance of the maternal chromosome leads to Angelman syndrome. Although there is no consensus on the cause, patients with Prader Willi syndrome never feel satiated, so will continue to eat indefinitely.


  1. https://www.noo.org.uk/NOO_about_obesity/obesity_and_health/health_risk_child
  2. Siebenhofer A, Jeitler K, Horvath K, Berghold A, Posch N, Meschik J, Semlitsch T. Long-term effects of weight-reducing drugs in people with hypertension. Cochrane Database of Systematic Reviews 2016, Issue 3. Art. No.: CD007654. DOI: 10.1002/14651858.CD007654.pub4
  3. http://ghr.nlm.nih.gov/condition/congenital-leptin-deficiency