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What is Refeeding Syndrome?

Written by Talia Cecchele

Highly Specialist Eating Disorder Dietitian and Founder of TCN

what is refeeding syndrome

You may be familiar with the term refeeding syndrome if you or someone you know has been in recovery from an eating disorder or been admitted to a hospital and assessed for malnutrition. Assessing refeeding syndrome risk is part of dietetic training, and I guess some would say it is the "bread and butter" of many clinical dietitians work.

Refeeding syndrome can develop when people start the nutritional rehabilitation phase of recovery from an eating disorder, so it is important to be aware of what it is and how to reduce the risk of it developing.

What is Refeeding Syndrome?

Refeeding Syndrome is a rare, but potentially serious complication that can occur if a person introduces large amounts of food or drink back into their diet quickly after a period of starvation or inadequate dietary intake. It is defined by a severe shift in fluid and electrolytes, commonly potassium, phosphate and magnesium.

How Does Refeeding Syndrome Develop?

When the human body is in a starved state or is receiving inadequate nutrition over a prolonged period (as short as 5 days), it switches from using carbohydrates as a preferred energy source, to utilising more energy from fat stores and breaking down muscle. The body can also become depleted in nutrients and electrolytes such as sodium, magnesium, potassium and phosphate. These are key electrolytes which support the regulation of fluids in the body and in muscle contraction.

These electrolytes are used by the body to metabolise food (produce energy from the food we eat) so when large amounts of food are reintroduced after a period of starvation, especially carbohydrates, the body uses these electrolytes for breaking down food, leaving less for other body functions. The drop in the much needed electrolytes in our blood can trigger severe shifts in fluid and electrolyte balances, meaning that important functions such as muscle contraction are compromised. Although serious cases are rare because we now know how to safely manage refeeding syndrome risk, complications can lead to seizures or cardiac arrest which can be life threatening.

What Are The Signs and Symptoms of Refeeding Syndrome?

It is important to be aware of any red flags of refeeding syndrome as there is some overlap with general feelings of being unwell or side effects of living in a malnourished body. Common signs and symptoms to look out for are:

  • A drop in electrolyte levels in blood tests (your GP or doctor in hospital will keep an eye on this)

  • Delirium (sudden confusion or drowsiness)

  • Chest pain or an irregular heart beat

  • Fluid retention (oedema) in a person's legs, face or abdomen

  • Seizures

  • Muscle weakness, muscle twitching of tremors

  • Gastrointestinal changes such as vomiting or diarrhoea

  • Feeling faint

  • Difficulty breathing

Am I at Risk of Developing Refeeding Syndrome?

The National Institute for Health and Care Excellence [1] has developed criteria for determining risk of developing refeeding syndrome. Risk is categorised as at risk, high risk or severe risk as follows:

At Risk

  • little or no nutritional intake for 5 days

High Risk

Meets criteria for 1 or more of the following:

  • BMI <16

  • Unintentional weight loss of greater than 15% body weight within the last 3-6 months

  • Little or no nutritional intake for 10 days

  • Low levels of potassium, phosphate or magnesium before feeding

Meets criteria for 2 or more of the following:

  • BMI <18.5

  • Unintentional weight loss of greater than 10% body weight within the last 3-6 months

  • Little or no nutritional intake for 5 days

  • A history of alcohol or drug abuse including insulin, chemotherapy, antacids or diuretics

Severe Risk

  • BMI <14

  • Little of no nutritional intake for >15 days

It is very important to highlight that you can develop refeeding syndrome at any weight or body shape, not just in people living in a low weight body. In fact, most of our and our dietetic colleagues experience of seeing refeeding syndrome develop has been in people who have presented in larger bodies and lost significant amounts of weight, and their risk of developing refeeding syndrome has sadly been overlooked. Once again highlighting the truth about BMI and eating disorders.

How is Refeeding Syndrome Risk Managed?

From a Nutrition Perspective

A registered dietitian will be able to support and guide you through the initial stages of nutritional rehabilitation to manage risk of developing refeeding syndrome. The key consideration is to gradually increase nutritional intake again to avoid severe shifts in electrolytes and to regularly monitor your electrolyte levels (through blood tests) so that these can be replaced through mineral supplementation if depleted.

Signs of refeeding syndrome can appear up to two weeks after nutritional rehabilitation begins, so it is important to monitor bloodwork and not to rush nutrition intake for the first two weeks.

A registered dietitian will devise a "refeeding meal plan" which will outline the graded steps to returning back to a normal diet. They will calculate the starting point, using clinical guidelines such as those outlines in MEED [2], to determine how much energy your body requires to safely work through the period of risk. Some factors which a dietitian will consider when creating their recommendations are:

  • spreading out meals and snacks, to avoid a large intake of carbohydrates

  • including lots of phosphate rich foods (mainly dairy)

  • limiting high carbohydrate fluids (juice, soft drink, cordial) and high sugar foods (lollies, chocolate, ultra processed foods)

  • limiting fluid intake to a normal level, usually calculated based on body weight and hydration status which is monitored through blood tests

If you are worried that you meet the criteria for developing refeeding syndrome and are in recovery from an eating disorder, it is very important that you speak to your GP and a dietitian to create an appropriate meal plan and arrange blood tests to have electrolyte levels checked.

As much as it is important not to delay starting eating and drinking, as continuing not to eat or drink can further increase risk of developing refeeding syndrome and worsening malnutrition, it is important not to eat more normally again without having an assessment from an appropriately qualified health professional. If you are experiencing any symptoms of refeeding syndrome, we recommend that you present to your nearest emergency department.

From a Medical Perspective

Medical management of refeeding syndrome risk is equally important as following a refeeding meal plan (if not more important) as monitoring blood work for changes to electrolyte levels is one of the key steps to reducing refeeding syndrome complications. It might be that your GP advises blood tests anywhere from daily to 1-2 times a week for the first 2-3 weeks to monitor electrolytes, in addition to checking your heart rate and blood pressure.

If a person is assessed to be at high risk or severe risk of developing refeeding syndrome, a short inpatient admission might be recommended as blood work and potential complications can be closely monitored.

In addition to monitoring, your GP and/or dietitian will likely recommend to take nutrition supplements if you are at a high-severe risk of developing refeeding syndrome. These supplements have strong evidence behind them to reduce the risk of refeeding syndrome complications. As per NICE [1] guidelines, it is recommended to start the following nutrition supplements before any changes to diet are made:

  • Thiamine 200-300mg daily

  • Vitamin B Co Strong 1-2 tablets, 3 times a day

  • A balanced multivitamin such as Forceval

Depending on blood work, your Doctor might also prescribe supplements of potassium, phosphate or magnesium if these electrolytes are low before starting on a refeeding meal plan, or if the levels of these electrolytes drop while nutritional intake is being restored.

For most people, after 1-3 weeks of regular and adequate food and fluid intake, the risk of refeeding syndrome developing will have passed and you can continue to work on building your relationship with food, returning to a healthy weight (if applicable) and your recovery.

To learn more about the nutritional rehabilitation process, eating disorder recovery and its complications, read our articles on going "all in", hypermetabolism, digestive issues and starvation syndrome.

If you need support in your eating disorder or disordered eating recovery, we offer 1:1 support at the TCN clinic to help you overcome food rules and find food freedom. You can find out about more about how we can support you here.

P.s. you can find parts of this article translated into German, in this blog post written by Romy Horbe, CCI trained recovery coach based in Germany!

Talia Cecchele

Specialist Registered Dietitian


[1] National Institute for Health and Care Excellence (NICE), 2006. Clinical guideline [CG32] Nutrition Support for adults: oral nutrition support, enteral tube feeding and parenteral nutrition. Available at: Nutrition Support for Adults ( [Accessed 28 April 2023].

[2] Medical Emergencies in Eating Disorders (MEED), 2022. Guidance on recognition and management [CR233]. Available at: Royal College of Psychiatrists ( [Accessed 28 April 2023].


Talia Cecchele Nutrition is a team of registered dietitians that specialise in eating disorder recovery, disordered eating, digestive issues and sports nutrition. We aim to bring balance back to nutrition, help you to break free from food rules and find food freedom. We offer virtual consultations and group programs so whether you are based in London, the United Kingdom or around the world we would love to support you. To enquire about a private consultation please fill out a contact form.



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