What is a Healthy Weight
How to measure your Body Mass Index
Adults: A convenient way for you to assess whether your weight is in the healthy range is by using the Body Mass Index (BMI). Your BMI is calculated by dividing weight in kilograms by height in metres squared. For example, a woman 1.67m in height and weighing 65kg would have a BMI of 23.3 which falls within the healthy weight range. Overweight is measured as 25 or more with obesity determined as 30 or more.These cut-off points are based on associations between chronic disease and mortality and have been adopted for use internationally by the World Health Organisation.
The classification table below used in conjunction with a BMI calculator calculator can assist you to assess whether you weight is in the healthy range.
Classification of Body Mass Index
Classification | BMI | Risk of co-morbidities |
|---|---|---|
| Underweight | <18.50 | Low (but possibly increased risk of other clinical problems) |
| Normal range (Healthy Weight) | 18.50 - 24.99 | Average |
| Overweight: | >25.00 |  |
| Preobese | 25.00 - 29.99 | Increased |
| Obese class 1 | 30.00 - 34.99 | Moderate |
| Obese class 2 | 35.00 - 39.99 | Severe |
| Obese class 3 | >40.00 | Very severe |
What factors may affect your weight
While there are many factors involved, an increase in body weight always results from an imbalance between energy intake (food) and energy expenditure (metabolism, thermogenesis and physical activity). An increase in body weight can also result from an increase in muscle mass. This is a consideration for people who participate in regular weight training, and does not reflect unhealthy weight gain.Why do energy imbalances occur?
While everyone is at risk of at least becoming overweight in the modern ‘obesogenic’ environment, particular factors influence why weight is gained. These include:- Previous history of weight loss. The effects of weight cycling – frequent large gains and losses – on long term health are unclear, but there are associations between the number of failed weight loss attempts and current body weight, as well as health risks.
- Life Stage. Weight gain is common, although not inevitable, at various life stages – for example, after pregnancy, and during menopause.
- Life events. Certain life events – such as marriage, giving up sport, and quitting smoking – can cause weight gain. Weight gain after quitting smoking can be significant (i.e. 5 kg in the first year). For this reason, instituting a weight management plan at the time of quitting may help reduce the weight gain that normally occurs after quitting.
- Family, work and social environments. Can influence weight gain and the inability to lose weight.
- Genetic influences. Genetic predisposition can influence the amount and rate at which weight is gained and lost.
- Stress. May need to be considered as a factor that can cause either weight gain or weight loss, depending on the person’s reaction to stress.
- Medical conditions. Certain medical conditions, for example, hypothyroidrism, are known causes of overweight.
- Medical treatments. Prescription medications can exacerbate weight gain (in particular, benzodiazepines, corticsteroids, anti-psychotics, tricyclic antidepressants, anti-epileptics, sulphonylureas, and insulin).
http://www.health.gov.au/internet/wcms/publishing.nsf/content/health-pubhlth-strateg-hlthwt-obesity.htm