Nutritional Assessment


Nutritional assessment is the systematic process of collecting and interpreting information in order to make decisions about the nature and cause of nutrition related health issues that affect an individual (British Dietetic Association (BDA), 2012).

This differs from nutritional screening which is a brief risk assessment which can be carried out by any healthcare professional and which may lead to a nutritional assessment by a dietetician.

Following a structured assessment path enables health professionals to carry out a quality nutritional assessment in order to identify those who need nutritional intervention, and to improve clinical decision making using a person centred approach. The process promotes consistent quality of practice; is user friendly; and allows effective monitoring of patients. A structured assessment pathway does not remove autonomy; it encourages professional judgement and informed decision making at every stage. The process provides a rationale for the nutritional intervention, and allows for revision of the plan as individual circumstances change over time.

BDA nutrition and dietetic care process (BDA, 2012)


A: Anthropometry

Anthropometry allows for an assessment of the different component parts of the human body. Body composition refers to the anatomical makeup of the body in terms of bone, muscle, water and fat. A single measure will not provide a comprehensive overview of the patients’ condition and so a number of measurements are required to form a more reasoned assessment.  In malnutrition, changes in body composition lead to Introduction to Malnutrition.

Anthropometric measurements that can be used to assess body composition.

MeasurementEquation/ methodInterpretation of results
Weight and % weight change% weight change = (previous weight – current weight / previous weight) x 100A patient is indicated for nutrition support if they have:
• BMI <18.5kg/m2Unintentional weight loss of >10% in the previous 3-6 months

• BMI <20kg/m2 and unintentional weight loss >5% in the previous 3-6 months.

(NICE, 2006)
Body mass index (BMI)BMI (kg/m2) = weight (kg) / height 2 (m2)• If BMI <18.5kg/m2 patient is underweight

• If BMI 18.5-25kg/m2 patient is in normal BMI range

• If BMI >25kg/m2 patient is overweight

(WHO, 2016)
Mid upper arm circumference (MUAC)Involves measuring the circumference of the mid-point on upper arm using a tape measure. This is a surrogate measure of both fat mass and fat free mass. It is a useful measure when a person cannot be weighed or if their weight is not likely to be a true reflection of the persons’ actual weight, e.g. if the patient has oedema or ascites.• If MUAC is >23.5cm the patient is likely to have a healthy BMI and is at low risk of malnutrition.

• If MUAC is <23.5cm the patient is likely to have a BMI <20kg/m2 and may be at risk of malnutrition.

(BAPEN, 2011)
Skin fold thicknessMeasurement requires a trained person using skin fold callipers which have been calibrated. Skin fold measurements can be taken at 4 different sites: suprailliac, subscapular, biceps, triceps (TSF; most commonly used). Measurement should be repeated 3 times and the mean result recorded. This is a surrogate measure of total fat mass. Longitudinal measurements can be used to identify any changes in fat mass.Centile tables can be used to interpret skin fold thickness measurements.
Mid arm muscle circumference (MAMC)MAMC is a surrogate measure of fat free mass and is calculated using MUAC and TSF.

MAMC (cm) = MUAC (cm) – 3.14 x TSF (cm)
Centile tables allow assessment of changes in total body muscle mass over time.

Other visual signs may indicate recent weight loss such as loose jewellery, baggy clothes, extra notch in belt, ill-fitting dentures, loose or thin looking skin, and prominent bony features.

B Biochemistry

The blood tests conducted within a nutrition assessment are interpreted in conjunction with a clinical examination; previous medical history; and current medications. Biochemistry tests measure levels of chemical substances present in the blood. Functional tests measure the function of vital organs such as the kidneys or liver.

MeasurementRationaleNormal range (note that different laboratories may use different reference ranges)
Haemoglobin (Hb)Assess for iron status or indicate anaemia.Women = 12.0 to 15.5 g/dl
Men = 13.5 to 17.5 g/dl
Albumin (Alb)A low level may indicate inflammation or infection is present, therefore should not be used to determine nutritional status.35 – 50 g/L (3.5 – 5.0 g/dL)
C-Reactive Protein (CRP)This is an inflammatory marker which is raised when infection or inflammation is present.Ideally <10 mg/L
White cell count (WCC)Immune system marker; is raised if infection is present.4-11 x109/L (4000-11,000 per cubic millimetre of blood)
Glycated Haemoglobin (HbA1c)Indicates an average blood sugar level over a period of months.Ideally <48 mmol/mol or <6.5% (Diabetes UK)
Sodium (Na)This is an indication of hydration status and kidney function. A raised sodium level may indicate dehydration.135-145 mmol/L
Urea (Ur)Used to assess kidney function. High urea and other markers levels in combination may indicate dehydration.2.5-7.1 mmol/L
Calcium and PhosphateUsed as a baseline when assessing risk of refeeding syndrome Calcium is adjusted for albumin levelAdjusted Ca 2.0-2.6 mmol/l
Phosphate 0.7-1.4 mmol/l
MagnesiumLikely to be low if there are large GI losses0.7-1.0 mmol/l
MicronutrientsInclude vitamins and trace elements. These are affected by the acute phase response if inflammation or infection is present and so best measured when CRP is low

C Clinical

A person’s disease state may increase the risk of malnutrition due to increased energy requirements; reduced energy intake; or increased nutritional losses. Examples of diseases/conditions where this may occur include:

  • Cancer
  • Chronic Obstructive Pulmonary Disease
  • Heart failure
  • Gastrointestinal disorders such as Crohns disease, liver disease, coeliac disease
  • Neurological conditions such as stroke, Motor Neurone Disease, Parkinsons Disease, multiple sclerosis, dementia
  • Burns, surgery or trauma
  • Mental health conditions (such as depression)

Symptoms that may impact on a person’s nutritional status either through reducing nutritional intake or increasing nutritional losses include:

  • altered bowel movements e.g. diarrhoea, constipation
  • upper gastrointestinal upset e.g. reflux, bloating, nausea, and vomiting.
  • early satiety
  • dysphagia
  • lethargy

D Dietary

Energy requirements

  1. Estimate Basal Metabolic Rate (BMR) using Henry Equations (2005) based on age, gender and weight (Henry, 2005) or estimate requirements for stable patients using 25-35kcal/kg (NICE 2006).
  2. Add factor when patient is metabolically stressed
  3. Add factor for activity and diet induced thermogenesis
  4. If aiming for weight gain, add 400-600 kcal/day. Only add this for patients who are metabolically stable (i.e. not acutely unwell).
  5. There are a number of alternative methods to calculate energy requirements in patients who are obese, with care required not to over-estimate requirements.

(Weekes and Soulsby, 2011)

Fluid requirements:

Aged >60 years = 30ml/kg body weight

Aged <60 years = 35ml/kg body weight (Todorovic and Micklewright, 2011)

Dietary assessment:

An estimation of the total daily calorie intake, as well as overall quality of diet should be assessed. Asking the patient (or their family/carer if patient unable) about their daily dietary intake will help understand patterns of eating, portion sizes, cooking methods and types of food and drink taken. Consider asking the following questions to help form a better understanding of the patients’ overall diet:

  • What is the patients’ typical food and fluid intake? This can be recorded using food record charts; 24-hour recall; 3-day food diary; or typical day diet history.
  • Is the patient eating 3 meals a day?
  • Do they have pudding after at least one meal per day?
  • Are they eating snacks in between meals?
  • Are they eating smaller meals than they used to when they were feeling well?
  • Are they having regular drinks, at least 6-8 glasses of fluid/ day?
  • Are they having nutritious drinks such as milky tea/coffee, fruit juice, milky drinks?
  • Are they having carbohydrate foods (bread, potatoes, pasta, rice, breakfast cereals etc) and protein foods (meat, cheese, beans, egg, fish, milk, yoghurt, cream) at each meal time? Portion sizes should be at least the size of the patient’s fist and amount to 1/3 each on the plate (carbohydrate, protein, vegetables).
  • Are they eating at least one portion of fruit or vegetable each day?
  • If food is being blended, are they adding nutritious liquids such as milk, cream or gravy to aid blending, rather than water?
  • Are they able to cook for themselves?
  • Do they have access to essentials such as bread, milk and cheese on a daily basis?
  • Do they have a hot/cooked meal each day?
  • Are they taking any nutritional supplements? Do they take them as recommended? Do they like them?

E Environment

Ability to shop, cook, assistance with eating and drinking, mobility, budget restraints, limited storage facilities, meal timings, family support.Appetite, dentures, dexterity, use of cutlery, sight, taste changes, nausea, vomiting, heart burn, bloating, early satiety, diarrhoea, constipation, pain, breathing difficulties, dysphagia (swallowing problems), food intolerances, special diets, diminished thirst, taste preferences.

Refeeding syndrome can be defined as the potentially fatal shifts in fluids and electrolytes that may occur in malnourished patients on refeeding following a period of starvation (NICE, 2006). This is particularly common in patients receiving artificial refeeding, but is possible with oral refeeding (particularly if oral nutritional supplements are prescribed). The patient should be considered at risk of refeeding syndrome if they meet the following criteria (NICE 2006).

If the patient has one or more of the following:

  • Body mass index <16 kg/m2
  • Unintentional weight loss >15% in the past three to six months
  • Little or no nutritional intake for >10 days
  • Low levels of potassium, phosphate, or magnesium before feeding

Or the patient has two or more of the following:

  • Body mass index <18.5 kg/m2
  • Unintentional weight loss >10% in the past three to six months
  • Little or no nutritional intake for >5 days
  • History of alcohol misuse or drugs, including insulin, chemotherapy, antacids, or diuretics

If the patient is considered to be at high risk of refeeding syndrome, the following steps are advised by NICE (2006):

  • Start nutrition support at a maximum of 10 kcal/kg/day, increasing levels slowly to meet or exceed full needs by 4–7 days
  • Restore circulatory volume and monitoring fluid balance and overall clinical status closely
  • Provide immediately before and during the first 10 days of feeding: oral thiamine 200–300 mg daily, vitamin B co strong 1 or 2 tablets, three times a day (or full dose daily intravenous vitamin B preparation, if necessary) and a balanced multivitamin/ trace element supplement once daily
  • Provide oral, enteral or intravenous supplements of potassium (likely requirement 2–4 mmol/kg/day), phosphate (likely requirement 0.3–0.6 mmol/kg/day) and magnesium (likely requirement 0.2 mmol/kg/day intravenous, 0.4 mmol/kg/day oral) unless pre-feeding plasma levels are high. Pre-feeding correction of low plasma levels is unnecessary

The information gathered as part of the assessment should be reviewed and synthesised and from this a nutritional diagnosis should be determined.


The alterations in the client/group/populations’ nutritional status.


The related factors contributing to the existence of, or maintenance of pathophysiological, psychosocial, situational, developmental, cultural, and/or environmental problems.

Signs and Symptoms

The defining characteristics are a cluster of subjective and objective signs and symptoms established for each nutritional diagnosis. The defining characteristics are gathered during the assessment phase and provide evidence that nutrition related problem exist.

The next phase of the care process is the intervention, which is divided into the plan and implementation.



Identify the overall aim of treatment. It may be minimise further losses, prevent further weight loss, maintain nutritional status, increase weight or improve nutritional status.

Dietetic Goals

Identify several short term goals/ action points that will be changed as a result of the assessment.

These should be written as SMART goals (Specific, measurable, achievable, realistic, and timely). The goals should be negotiated and agreed between the health care professional and the patient or carer.

A timeframe for follow up and review should be agreed upon.

The implementation and monitoring phases of the care process will be discussed in subsequent sections.


British Association of Parenteral and Enteral Nutrition (BAPEN) Malnutrition Universal Screening Tool (MUST)

British Dietetics Association (BDA) (2012) Model and Process for Nutrition and Dietetic Practice.

Henry (2005) Basal metabolic rate studies in humans: measurement and development of new equations. Public Health Nutrition. 8: 1133-1152

National Institute of Clinical Excellence (NICE) (2006) Nutritional Support in Adults

Scientific Advisory Committee on Nutrition (SACN) (2011) Dietary Reference Values for Energy. London: TSO

Todorovic, V.E., and Micklewright, A. (2011) A pocket guide to clinical nutrition fourth edition. Parenteral and Enteral Group of the British Dietetic Association.

Weekes, L and Soulsby C (2011), in Todorovic, V.E., and Micklewright, A. (2011) A pocket guide to clinical nutrition fourth edition. Parenteral and Enteral Group of the British Dietetic Association.

World Health Organisation (WHO) 2016