saudigastro.com/patients/malnutrition-refeeding
Category
Serious
Red flags
5
This article is educational and does not replace your doctor's advice. Seek urgent care for any red-flag symptoms.
What is it?
Malnutrition is a state in which a person does not get, or cannot absorb, enough energy, protein, vitamins or minerals. It leads to loss of weight and muscle, weakness, slower healing and a higher risk of infection. It can affect adults and children, and it can occur in people who are underweight as well as in people with a normal or even high weight who have lost weight unintentionally or have vitamin and mineral deficiencies. Refeeding syndrome is a different, serious risk: when a person who has eaten very little for days or weeks starts to eat or is given feeding again, the body shifts quickly in its use of sugar and minerals. Blood levels of phosphate, potassium and magnesium can fall sharply, and this can affect the heart, muscles and brain.
How common is it?
Malnutrition is common in people with digestive and liver diseases such as inflammatory bowel disease, coeliac disease, pancreatic disease, cirrhosis, bowel obstruction, cancer and after some operations. It also affects older people, people with swallowing problems, depression, eating disorders or alcohol dependence, and people with limited access to food. It is often under-recognised, so screening is valuable. Refeeding syndrome is less common but can be life-threatening in those at risk.
Why does it happen?
Malnutrition develops when intake is too low (poor appetite, nausea, pain on eating, swallowing difficulty, depression, limited food), when absorption is poor (for example in coeliac disease, Crohn disease, pancreatic insufficiency or after bowel surgery), when losses are high (vomiting, diarrhoea, fistulas), or when the body needs more than usual (infection, cancer, burns, chronic inflammation). Refeeding syndrome happens after prolonged low intake: when feeding restarts, insulin rises and pulls phosphate, potassium and magnesium into cells, so their blood levels drop. Risk is higher with very low body weight, recent rapid weight loss, little or no food for many days, alcohol dependence, and long-term illness.
Symptoms
- Unintentional weight loss, clothes becoming loose
- Tiredness, weakness and poor concentration
- Loss of muscle, a hollow face, thin arms and legs
- Feeling cold, dry skin, hair loss, slow wound healing
- Frequent infections
- Low mood, irritability or poor appetite
- Swelling of the ankles or feet (fluid) in more severe cases
Red flags — seek urgent medical care
Palpitations, chest pain, fainting or an irregular heartbeat, especially after starting to eat again after a long period of poor intake
Possible refeeding syndrome or a dangerous mineral imbalance. Go to the emergency room now.
Muscle weakness, numbness, cramps, seizures, confusion or difficulty breathing
Severe low phosphate, potassium or magnesium, or other serious illness. Call emergency services.
Rapid weight loss with persistent vomiting, or being unable to keep any fluids down
Risk of dehydration and electrolyte problems. Seek urgent medical care the same day.
A child or baby who is not feeding, is unusually sleepy or limp, or has stopped growing or losing weight quickly
A child needing urgent care must be seen immediately; go to the nearest emergency department.
Unexplained weight loss of more than a few kilograms over weeks to months, with blood in stool, persistent pain or difficulty swallowing
May reflect a serious underlying illness. Arrange urgent medical review.
How is it diagnosed?
Doctors and dietitians use simple screening questions about recent weight loss and appetite, measure weight, height and body mass index, and look for loss of muscle and fat. Blood tests can show anaemia, low vitamins and minerals, and poor kidney or liver function; blood protein levels alone are not a reliable measure of nutrition. If you are at risk of refeeding syndrome, phosphate, potassium, magnesium and blood sugar are checked before and during feeding. Further tests look for the cause of the poor intake or absorption, such as coeliac blood tests, stool tests, scans or endoscopy.
What the latest science says
Current practice recommends screening everyone in healthcare settings for malnutrition risk, identifying people at risk of refeeding syndrome before feeding starts, and beginning nutrition support at a low level and increasing it gradually, with vitamin B1 (thiamine) and mineral replacement and close monitoring. Early nutrition support is encouraged because delaying it can worsen outcomes.
Outlook — what to expect
Most people improve with the right nutrition support and treatment of the underlying cause, although recovery of weight and strength can take weeks to months. Refeeding syndrome is largely preventable when it is recognised and feeding is restarted slowly under supervision. Untreated malnutrition can lead to complications, so seek help early.
Treatment
Habits & Lifestyle
If you are only mildly underweight and well, small steps can help. If you have eaten very little for many days, do not restart a full diet on your own; see a doctor first.
- Eat little and often: aim for three meals and two or three snacks a day rather than waiting for hunger.
- Weigh yourself weekly at the same time and keep a record to show your doctor.
- Gentle activity, such as walking and light strength exercises, helps to rebuild muscle once your team agrees.
- Do not use fad diets, long fasting or unprescribed supplements to gain or lose weight.
- Tell your doctor about low mood, difficulties with swallowing, dental problems or money worries that limit your eating.
Diet
The aim is to increase energy and protein in manageable amounts. A dietitian can create a plan that suits your condition, taste and culture.
- Add energy to normal foods: olive oil, butter or ghee, full-fat milk or yoghurt, nuts, nut butters, tahini, dates, and eggs.
- Include a protein source at every meal, such as fish, chicken, meat, eggs, legumes, dairy.
- Prescribed oral nutritional supplement drinks can be used between meals when advised.
- If you have a condition such as coeliac disease or lactose intolerance, adjust the foods you choose; do not simply remove food groups on your own.
- After a long period of little food, your team may start nutrition at a low level and increase it over several days; follow their plan exactly.
Medications
Medicines are used to treat the cause, replace missing nutrients and prevent refeeding problems. Your doctor decides what you need; do not start supplements in high amounts on your own.
- Vitamin B1 (thiamine) is usually given before and during refeeding in people at risk.
- Phosphate, potassium and magnesium are replaced by tablets or drips guided by blood tests.
- Multivitamins, iron, vitamin D, vitamin B12 or other supplements are given when tests show a deficiency.
- Medicines for nausea, pain or diarrhoea, or to treat the underlying disease, may help you eat better.
Procedures & Surgery
When eating by mouth is not enough or not possible, nutrition can be given in other ways under medical supervision.
- A thin feeding tube through the nose into the stomach or bowel (nasogastric tube) can provide liquid feeds in the short term.
- For longer feeding support, a tube placed into the stomach through the skin (gastrostomy) may be arranged.
- If the gut cannot be used, nutrition can be given into a vein (parenteral nutrition) in hospital or sometimes at home with specialist support.
- Procedures such as endoscopy may be used to find and treat the cause, for example a narrowing.
Living with the condition
- Regular follow-up with a dietitian and doctor helps to catch problems early.
- Ask family and friends to support meal planning and shopping.
- Bring a record of your weight and what you eat for a few days to your appointments.
In the Saudi context
During Ramadan or other periods of fasting, people who are malnourished, pregnant, elderly, or who have a digestive or liver illness should speak to their doctor before fasting, as it may not be safe. Traditional foods such as dates, labneh, nuts, tahini, eggs and olive oil can be used to add energy and protein.
Questions to ask your doctor
Save this list or print it before your appointment — doctors appreciate prepared patients.
- How much weight should I regain, and how quickly?
- Am I at risk of refeeding syndrome, and do I need to be monitored?
- Which vitamin and mineral levels should be checked?
- Do I need supplement drinks or tube feeding?
- What is causing my poor intake or absorption, and how will it be treated?
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Status: Approved for publication by SGA; individual clinician review is ongoing · Published 24/04/2026
For general education only; it does not replace your doctor’s advice. Individual clinician review of this guide is ongoing. SGA clinician? Review this guide