Assessment
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Body Mass Index and Waist Circumference
Usual Dietary Intake, Pattern of Eating, Eating Behaviour
Medical History and Medication
Assessment of the client before they begin weight management is very important. Identifying specific difficulties they may have in controlling their weight can be the key to success.
Body Mass Index and Waist Circumference
Body mass index (BMI) and waist circumference can be used to determine the degree of obesity and risk to health.
BMI
Ask the client to remove outer clothing and shoes. Weigh them and measure their height.
BMI = Weight (kg) / Height (m2) or use the BMI ready reckoner
e.g. for someone weighing 95kg and height 1.6m
BMI = 95 / (1.6 X 1.6) = 37kg/m2
Interpretation of BMI:-
| BMI | Description |
|---|---|
| > 40 | morbidly obese (serious risk to health) |
| 30 - 30.9 | obese (risk to health) |
| 25-29.9 | overweight (health could suffer) |
| 19-24.9 | healthy weight |
| < 18.9 | underweight |
Waist
Waist circumference can be useful for clients who cannot be weighed and as an additional measure of risk to health. The risk to health associated with waist circumference is independent of height. Measuring waist is a good tool for following progress of fat changes and is particularly useful when someone becomes more physically active. Under these circumstances muscle mass may increase resulting in little change in weight but fat will continue to be mobilised.
With the client in a standing position measure midway between the lowest rib and the suprailiac crest.
| Increased Risk to health | Substantial Risk to health | |
|---|---|---|
| Male | > 94 cm / 37 in | > 102 cm / 40 in |
| Female | > 80 cm / 32 in | > 88 cm / 35 in |
Men of South Asian origin have an increased risk to health with a waist circumference > 90cm (36 inches).
Readiness to Change
Readiness to change can be assessed by asking the client to rate themselves on a scale of 1-10 on how important they think it is for them to lose weight and how confident they feel to make changes.
Discuss
- their reasons for the number they picked
- what it would take for them to move up the scale
Weight/Dieting History
The history of a client's weight and previous weight loss attempts are useful in assessment to identify:
- causes of weight gain
- previous success/failure
- evidence of short-term/quick fix approaches
Suggestions for assessment questions
Usual Dietary Intake, Pattern of Eating, Eating Behaviour
| Frequency Amount Type |
of foods eaten and meal patterns enable the client and clinician to identify problem areas for change. |
Under-reporting of dietary intake is a common problem in overweight and obese people so taking a detailed diet history may not be useful.
The following suggestions can be used to assess intake and behaviour.
Physical Activity
Energy balance and weight is determined by both energy intake and energy expenditure.
Energy Balance = Energy Intake - Energy Expenditure
An increase in physical activity above the client's usual level will help to initiate weight loss or prevent further weight gain. The following tools can be used to assess physical activity level.
- Pedometer - records number of paces taken or distance walked giving clients a simple measure of physical activity to change.
- Ask the client to keep an activity diary:-
e.g. sat for 3 hours, walked for 30 minutes etc.
Social/Work Circumstances
Eating behaviour can be strongly influenced by social and work circumstances. Assessment can be made by questionnaire:-
Medical History and Medication
It is important to obtain relevant medical history and details of any drugs taken by the client. Some medical conditions and drugs can cause weight gain or make weight loss more difficult (Medication and Weight Gain)
Eating Disorder
It has been estimated that 20-40% of obese people attending weight management programmes have binge eating disorder (Marcus M D 1985) If you suspect binge eating disorder, bulimia, night eating syndrome or other eating disorder it may be useful to refer the client to services for mental health.
The Scoff questionnaire can be used as a screening tool to raise suspicion of an eating disorder but is not diagnostic. Score one point for every YES. A score of 2 or more indicates a likely case of anorexia or bulimia nervosa. Similarly a score of 2 or more could raise suspicion of binge eating disorder.
References:-
Marcus M D et al. Binge eating and dietary restraint in obese patients. Addictive Behaviours 1985; 10:163-8
Morgan, J.F, Reid, F, Lacey, J.H. The Scoff questionnaire: assessment of a new screening tool for eating disorders. BMJ 1999;319:1467-8

