What is Refeeding Syndrome?

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Please note that this blog post is intended to provide you with education and information only. Please consult with your health care provider if you have any questions or concerns regarding refeeding syndrome.

First of all…..What is refeeding syndrome (RFS)?

Refeeding syndrome (RFS) is a medical condition that happens after a period of starvation. When you increase your nutrition quickly after starvation, your body can experience an imbalance in electrolytes, which can lead to harmful side effects.  Anyone who has been malnourished is at risk of RFS, and it is not limited to someone with an eating disorder, however, it is often seen with folx suffering from anorexia.

There are particular groups of people who are at risk of refeeding syndrome, including (Flesher, 2006):

  • Patients with protein-energy malnutrition
  • Anorexia Nervosa
  • Prolonged Fasting
  • No nutritional intake for 7+ days
  • Significant weight loss
  • Alcohol Abuse

When your body is adequately nourished, there is a constant flow of glucose (a carbohydrate) moving into your cells and replenishing itself into your bloodstream to keep the environment at a comfortable level. This state of comfort where your body functions adequately is called homeostasis (aka balance).

After your body has gone through a period of malnourishment (meaning, it has not been getting the energy or the nutrients it needs to survive and function properly), it can go into a period of shock if you try to re-nourish it too quickly. Your body literally says “woah, hold on, what are all of these nutrients!? I haven’t seen these in so long!”.

The human body LOVES glucose as it is its primary source of fuel. When your body is starving, it lacks the ideal fuel it needs (aka. Carbohydrates) to function, so it turns to fat and protein to provide it with energy. This may be fine for a little while, but the body is way more efficient when it has carbohydrates for energy, so with time…. this plan will backfire.

When you start to nourish your body again with a variety of nutrients, the carbohydrates will create a spike in a hormone called insulin. Insulin helps the carbohydrates to enter your cells and turn it into energy (Mahan, 2017).

Because your body hasn’t seen this super-duper awesome source of energy in a while, it gets so excited that it just soaks it aaaaalllll up. You know when you have a really dry sponge and then you run it underwater, how quickly it absorbs the water and becomes all flexible and functional again? It’s kind of like that.

Sooo why should I be concerned? Isn’t it a good thing that I am giving my body the nutrients it needs to survive?

Yes!!! Nourishing your body is ALWAYS great. And, we want to be mindful of how your body will respond because there are many complications that are secondary to refeeding syndrome.

During the period of refeeding syndrome, your cells will absorb all of the glucose it’s been missing as well as overconsume certain minerals, such as phosphorus, potassium, and magnesium. Since your cells are taking all of these nutrients in, there is not enough left to circulate in your bloodstream, which can result in low electrolytes in your blood. Your electrolytes play a role in carrying electric charges to maintain bodily processes, such as your heart or your lungs (Mahan, 2017).

So, having low electrolytes in your bloodstream can result in some of the following complications (Runde, J. & Sentongo, T., 2019):

  • Electrolyte depletion
  • Fluid overload (water retention)
  • Arrhythmia (abnormal heart rate)
  • Seizure
  • Encephalopathy (brain damage)

As you can imagine, this response can be very dangerous and life-threatening, so it is best not to wait until you are showing symptoms before correcting refeeding syndrome.

What to expect when treating refeeding syndrome?

Your doctor and dietitian will work closely with you to gradually increase your food intake and monitor your body’s response to malnutrition. The treatment of refeeding syndrome may look different if you are in an inpatient or outpatient setting, however, your medical team will be able to support you and ensure that the re-nourishment process is done safely.

Generally, refeeding occurs within 5 days after the re-nourishment process has started, or in severely undernourished people (Mouillot, T. et al., 2021). Your treatment team will let you know if you are at high risk and they will monitor you closely for a minimum of 7 days.


Although refeeding syndrome may appear to be frightening, it should never stop anyone from increasing their nutrition or beginning the process of recovery. Refeeding syndrome is quite rare and only happens in a small percentage of patients, HOWEVER, the risk of continuing to starve your body is greater. A gradual reintroduction to nourishment is appropriate to maintain your health long-term and support your recovery.

Eating Disorder Recovery Program

Recovering from an eating disorder is not easy, however it IS possible. With the high demand for eating disorder services, and limited access to acute care, we have developed a virtual, outpatient eating disorder program to increase accessibility to recovery from the comfort of your own home.

This program includes:

  • Individualized session with a dietitian or psychotherapist (weekly)
  • Group sessions (weekly)
  • Meal support (weekly)
  • Parent, Caregiver, Partner support group (weekly)
  • Care coordination

Want to learn more about? Find more information on our website: https://www.thebalancedpractice.com/edprogram

Need support?👇

The Balanced Practice is a team of health care providers specialized in eating disorder outpatient treatment, disordered eating and intuitive eating. Our mission is to help folx heal their relationship with food and their bodies so they can live happily outside of diet culture!

We strive to provide evidence-based counselling to support you, or your loved one, in achieving full recovery. Schedule a connection call now.Written By Joelle Ciccarelli, RD

Revised by Marie-Pier Pitre-D’Iorio, RD, B.Sc.Psychology
Founder of  The Balanced Practice


Flesher, M. (2006). Refeeding Syndrome. Bad Gut Society. https://badgut.org/information-centre/a-z-digestive-topics/refeeding-syndrome/

Mahan, K., & Raymond, J. (2017). Krause’s Food and the Nutrition Care Process (14th edition). Elsevier.

Mouillot, T., Brindisi, M.C., Chambrier, C., Audia, S. & Brondel, L. (2021). Syndrome de renutrition inappropriée. Revue de la médecine interne, 42, 346-354. Doi : https://doi.org/10.1016/j.revmed.2020.12.012

Runde, J., & Sentongo, T. (2019). Refeeding Syndrome. Pediatric Annals, 48(11), 448-454. http://dx.doi.org.proxy.bib.uottawa.ca/10.3928/19382359-20191017-02

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