Normal weight obesity

All unapproved Citizendium articles may contain errors of fact, bias, grammar etc. A version of an article is unapproved unless it is marked as citable with a dedicated green template at the top of the page, as in this version of the 'Biology' article. Citable articles are intended to be of reasonably high quality. The participants in the Citizendium project make no representations about the reliability of Citizendium articles or, generally, their suitability for any purpose. This article is currently being developed as part of an Eduzendium student project in the framework of a course entitled Appetite and Obesity at Edinburgh University. The course homepage can be found at CZ:UoE Appetite and Obesity 2011. For the course duration, the article is closed to outside editing. Of course you can always leave comments on the discussion page. The anticipated date of course completion is 01 April 2012. One month after that date at the latest, this notice shall be removed. Besides, many other Citizendium articles welcome your collaboration!

The prevalence of obesity has risen rapidly over the years and shows no clear signs of slowing down. A great epidemiological representation of that can be seen in studies using the population of the US of A, collected from the 1960s to present time. It has shown that obesity in the population has increased from ~13% to almost 30%.

To clinically classify a person as being obese, their Body Mass Index (BMI) must be equal to or greater than 30kg/m2. However, the spectrum of obesity is quite large. Normal Weight Obesity (NWO), found in almost half of the American adult population, is when a person has a normal BMI (18.5- 24.9 kg/m2) or normal body weight but also has a high percentage of body fat(>23.1% for men and >33.3% for women) as well as heart and metabolic disturbances.

Measuring an individual’s BMI does not take into account a person’s muscle or bone mass and as both are denser than fat people can be calculated to have an ‘obese’ BMI while they actually have a healthy percentage of body fat. In contrast to this, a person can have a normal BMI and be in the normal weight range but actually have unhealthily high adiposity levels but according to their calculated BMI, they are not obese. High percentages of body fat tissue are high risk factors for the diseases and disorders linked to the obesity, including diabetes, ischemic heart disease, heart failure, hypertension and sleep apnea. Catriona Thompson 19:50, 25 October 2011 (UTC)

Measuring Normal Weight Obesity

Sawdah Jakda 16:04, 25 October 2011 (UTC)

The gold standard definition of obesity is considered to be an excess in Body Fat (BF) but the BMI is used by clinicians and epidemiologists as a means of defining the presence of adiposity and/or obesity. The advantages of using the BMI instead of BF values is that it is a lot more simple to use and it is easy to reproduce. Studies showing the association between extreme BMI values and increased mortality further support its usage. However, this test fails to differentiate between elevated BF content and preserved/ increased lean mass in patient with a BMI below 30kg/m2, those not clinically classified as obese.

The strong relationship between high Adiposity and metabolic disturbances makes it vital to try find a more accurate way in which to determine adiposity other than BMI.

The definition of metabolic syndrome covers the following criteria's:

1) Waist circumference (>102 in men and >88 in women)

2) HDL (<1.04mmol/L in men and <1.03mmol/L in women)

3) Triglycerides (>1.7mmol/L)

4) Blood Pressure (systolic blood pressure >130mmHg or diastolic blood pressure >85mmHg)

5) Fasting Glucose (>5.5mmol/L)

Disorders linked to NWO

When the fat content exceeds the lean muscle mass and body fat percentage is above 25% for men, and 35% for women, it is predicted that there is an increased risk of heart disease, diabetes, high cholesterol and high blood pressure. The possibility for these normal weight individuals to develop these conditions is said to be equivalent to overweight individuals.