"...all doctors should be able to diagnose and treat nutritional deficiencies."

Royal College of Physicians. Nutrition and Patients: A Doctor's Responsibility. London 2002


This page has been printed from the www.stewartnutrition.co.uk web site.

Rapid Unintentional Weight Loss

Unintentional and rapid weight loss can result in nutritional deficiencies developing within weeks and occasionally days.  Some deficiencies may influence the person’s appetite, energy level and resistance to infection and as a result may further delay the person’s recovery.

Those with this problem should already have received medical assessment and ideally input from an experienced dietitian or nutritional therapist.

Assessment of Those with Rapid Unintentional Weight Loss
Assessment should include determining the possible cause(s) and:

  • The degree of weight loss (percentage of body weight lost) and the degree of undernutrition (Body Mass Index <20.0 kg/m2) to calculate the risk of deficiencies developing, see report here.
  • The presence of Common Nutritional Deficiencies that are most likely to develop and adversely affect appetite or energy level
  • The need for nutrition support by use of:
    Dietary Treatment with selected drinks and foods
    Protein-energy supplements in the form of milk or soya-based drinks and
    Nutritional Supplements

Common Nutritional Deficiencies and their Early Features

Nutrient Early Features of Deficiency
Vitamin B1 – Thiamine Fatigue, nausea, loss of appetite, muscle pain on exercise, confusion, unsteadiness and difficulties with eye movements
Potassium Fatigue, weakness and palpitations
Magnesium Fatigue, weakness and muscle cramps
Anaemia Fatigue, weakness, shortness of breath, cold intolerance and palpitations
Iron Fatigue, poor or distorted appetite, sore tongue, cracking at the corners of the mouth, mouth ulcers
Zinc Poor appetite, poor vision in the dark, delayed wound healing and poor immune function
Vitamin C Fatigue, easy bruising, poor wound healing, poor resistance to infection and anaemia


Dietary Advice for Those with Rapid Weight Loss

The most pressing need is for energy, then protein, especially if there is a significant loss of muscle, and then many essential nutrients particularly vitamin B. 

Foods need to be chosen because they are nutritious, widely available, easy to prepare and some may need to be suitable for those with swallowing difficulties.

Foods and Drinks Suitable For Those with Rapid Weight Loss

Foods Main Nutrients Provided
Fruit juices – diluted if necessary Energy, potassium and vitamin C
Stewed Bramley cooking apples and sugar Energy, vitamin C, potassium
Home made vegetable soup Energy, potassium, magnesium and vitamin B
Prepared soup As above and sodium salt
White bread Energy, protein, iron, vitamins B1 and B3
Banana Energy, potassium and magnesium
Tea with milk and sugar Energy and a few nutrients
Scrambled egg Energy, protein, vitamin B and iron
Spinach with egg and cheese Energy, protein, vitamins B12, folate, B2, B3, iron, magnesium and calcium
Rice pudding Energy, vitamin A and B2, calcium and protein
Cheddar cheese                                                   Energy, calcium, vitamin B and zinc
Baked fish                                                            Energy, protein, vitamin B12
Tinned sardines Energy, protein, vitamin B12, zinc calcium and n-3 EFAs
Mashed or jacket potatoes                                Energy, potassium, magnesium, vitamin C and B
Chocolate                                                             Energy, potassium, magnesium and iron
Shepherd’s pie or other minced meat dishes  Energy, protein, iron, zinc, vitamins B and C
Fish pie (fish, milk, egg, cheese and potato) Energy, protein, calcium, vitamins A, B and C

If necessary the person may require a fortified drink such as Build-up or Complan which are available from a local chemist.

Nutritional Supplements for Those with Weight Loss

Often the most pressing need is for vitamins B and C.   Just such a recommendation was made for the ill and convalescing elderly in 1974 by an editorial in the British Medical Journal Old People’s Nutrition (BMJ 1974 February 9; 1(5901): 212-213) which stated:

“Many would agree that iron, vitamin C, vitamin D and the B-complex vitamins should be given for three to four weeks to elderly patients recovering from a severe illness of any type and the administration of vitamin C before an elective surgical procedure might also be considered”.


Suitable supplements might include:

  • Sanatogen Berocca: half of one effervescent tablet twice, three or even four times per day for at least 10 days (from chemists and some supermarkets).
  • A vitamin B and C tablet providing approximately 10 mg of the B vitamins and at least 100 mg of vitamin C (from health food shops).
  • An A-to-Z multivitamin: one per day with an additional vitamin B supplement providing at least 10 mg per tablet (available from numerous outlets).  They should be taken at separate times of the day.

For those with significant weight loss >10% of body weight it is better to give small amounts of a nutritional supplement three to four times per day during the convalescent period than giving a large supplement once per day.

It is prudent to check with the patient’s medical advisor that any nutritional supplements are suitable and are not contraindicated.

Copyright Dr. Alan Stewart M.B.B.S.M.R.C.P. (UK)M.F. Hom.
47 Priory Street, Lewes, East Sussex. BN7 1HJ
Tel 01273 487003 Fax: 01273 487576