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Malnutrition and Weight Loss

 

Summary

Malnutrition is both a cause and a consequence of ill health. It is common and increases a patient's vulnerability to disease1.


 

In Scope

  • Patients suspected to be malnourished +- weight loss

 

Not in scope

  • ARFID, Avoidant/restrictive food intake disorder: At time of writing there is no commissioned service for this in adults
     
  • Food Allergy

  • Eating Disorders
     
  • Patients already under specialist care at other centres.
     
  • RISH (restrictive intake self-harm): please note that due to the complex needs of these patients the Community General Dietetic Outpatient team cannot accept them. Please discuss/refer to Psychiatry as needed.Weight management – Please see RMS Obesity, Weight Management in the Community.


 

Red Flags

  • Refeeding Syndrome1
    • Patient has one or more of the following:
      • BMI less than 16 kg/m2.
      • unintentional weight loss greater than 15% within the last 3–6 months
      • little or no nutritional intake for more than 10 days.
      • low levels of potassium, phosphate or magnesium prior to feeding
    • Or patient has two or more of the following:
      • BMI less than 18.5 kg/m2.
      • unintentional weight loss greater than 10% within the last 3–6 months
      • little or no nutritional intake for more than 5 days.
      • a history of alcohol abuse or drugs including insulin, chemotherapy, antacids or diuretics.
  • BMI <14
  • BP <80/50
     
  • Postural drop >20 mmHg
     
  • Postural tachycardia >30bpm
     
  • QTc >450ms (females) or >430ms (male), unless due to known other cause such as medication
     
  • New ventricular arrhythmia
     
  • HR <40bpm
     
  • Temperature <34.5c
     
  • Electrolyte abnormalities: K <2.5, Na <130, Po4 <0.5

 

The above list is not exhaustive


 

Primary Care assessment and management prior to referral


 

Advice and guidance

Please send advice and guidance requests to e-RS.

If you have any general queries (not patient specific) about ONS prescribing, please contact ciosicb.prescribing@nhs.net.


 

Investigations required prior to referral

  • Calculate BMI
     
  • For patients not considered at risk of re-feeding syndrome please consider the following bloods (though referrals will be accepted without bloods if no re-feeding concerns)
    • Ferritin
    • Hb
    • B12
    • Vit D
    • Folate
       
  • For those patients at risk of re-feeding syndrome the following bloods are useful in addition to the list above:
    • U&Es
    • Bone
    • Magnesium

 

RCHT Low Body Weight Management Clinical Guideline Template has further information. Suggested monitoring investigations/bloods to be done by General Practice can be found in Section 2.6.1 and appendix 6.


 

Referral Criteria

Urgent Referral Criteria

Any red flag features please consider if medical admission required. Discuss with Acute GP as necessary.
 

Please send an urgent referral to Dietetics for patients at risk of refeeding syndrome –see criteria in red flag section above, alongside any urgent investigations or referrals based on the likely clinical cause for malnourishment.
 

If the patient is suspected of having an Eating Disorder please see the Adult Eating Disorders guideline.


 

Routine Referral Criteria

Consider a routine referral to Dietetics if any of the below criteria are met (alongside any investigations/referrals based on the likely clinical cause for the malnourishment):

  • Stable BMI of 18.5-20 kg/m².
     
  • BMI ≤20 kg/m² with ≥ 5% weight loss in 3-6 months.
     
  • Weight loss of 10% or more in 3-6 months.
     
  • Newly presented/accelerated dysphagia alongside urgent referrals/investigation into the cause.
     
  • Concerns regarding high nutrient loss/malabsorption.
     
  • Have non-healing wounds/high-grade pressure ulcers.
     
  • Disordered eating*
     
  • Nutritional goals are not being met after following ‘Food First’ advice for 1 month, followed by a trial of 2 first-line oral nutritional supplements for 2 weeks.

 

Consider referral for specific dietary advice as required below:

  • Nutritional assessment for enteral feeding.
     
  • Motor Neurone Disease.
     
  • Parkinsons.
     
  • Huntingtons disease.
     
  • Catabolism.
     
  • Liver disease.
     
  • Fibre modification.
     
  • Chronic pancreatitis.
     
  • Renal disease stage 1-3.
     
  • Specific nutrient advice.
     
  • High output stoma.
     
  • Dietary assessment of restricted diets to check if nutritional requirements are being met.

 

*Disordered eating refers to a spectrum of problematic eating behaviours and distorted attitudes towards food, weight, shape, and appearance. Often these behaviours include dieting, skipping meals, fasting, restricting food intake, eliminating specific foods or food groups, binge eating, excessive use of diuretics, laxatives, and weight loss medications, as well as the use of compensatory behaviours (purging, excessive exercising). Disordered eating patterns can vary in severity but do not meet the frequency, duration and/or psychological criteria for a diagnosable eating disorder. It often emerges in the context of, or alongside other co-morbidities or mental health difficulties, including trauma.


Note that dietetics are unable to provide domiciliary visits. The Community Dietetic service runs telephone and virtual clinics ONLY. Any face-to-face requests under extenuating circumstances will be discussed and agreed upon on a case-by-case basis.


 

Referral Instructions

Please include an up-to-date BMI with referral. A MUST score is useful but referrals will not be rejected if missing.

Send all referrals for Dietetics via e-RS.


 

Useful resources

Professionals

If you would like to book this training for your team please email: rcht.dietcomm@nhs.net and state ‘malnutrition training request’ in the title of the email.

 

Patient

 

References

 

Page Review Information

Date Reviewed:       12 January 2026

Next Review Due:   12 January 2028

Sifter name:            Dr Kate Northridge

Contributor:             Shannon Moore, Community Dietitian CFT