Refueling after a fast is extremely important. Some would say it’s even more important than the fast itself. In this article we discuss re-feeding syndrome and how to protect yourself from it.
This syndrome is a shift in fluids and electrolytes that occurs when reintroducing foods, fluids or artificial feedings (i.e. feeding tubes in hospitals). After a period of not eating, or under eating, the body goes through various hormonal and metabolic shifts. This means reintroducing food and fluids must be done carefully and strategically.
A few hallmark issues with re-feeding syndrome include: abnormal sodium and fluid balance, low phosphate, low potassium, low magnesium and low thiamine (a B vitamin) (1). Further symptoms are indicated in the chart below.
|Symptoms of Re-feeding Syndrome (4)|
|Cardiovascular||Arrhythmias, cardiomyopathy, low blood pressure, death||Low blood pressure, arrhythmias, heart attack, change in heart rate||Dysrhythmias|
|Neurological||Fatigue, weakness, confusion, loss of reflexes, loss of body movement, coma, cranial nerve palsies, diffuse sensory loss, Guillain-Barré-like syndrome, seizures||Fatigue, confusion or other mental status changes, decreased muscle strength, decreased reflexes, muscle spasms||Muscle cramps or twitching, weakness, loss of body movement, seizures, vertigo||Wernicke’s encephalopathy (vision changes, loss of body movement, confusion, hypothermia, coma) (1)|
|Respiratory||Respiratory failure||Slow breathing, respiratory distress, respiratory failure|
|Blood||Altered red blood cell function, anemia, haemorrhage, low platelets, white blood cell dysfunction||Anemia|
|Gastrointestinal||Constipation, paralysis of intestine muscles||Abdominal pain, diarrhea, constipation, loss of appetite|
How Does Re-feeding Syndrome Occur?
As mentioned above, this occurs with rapid food or fluid intake after hormonal and metabolic shifts from a period of fasting or under-nourishment. During fasting, the body begins to use fatty acids (ketones) for fuel. This results in an increase in blood levels of ketone bodies which the brain also uses as its main energy source. During the period of prolonged fasting, several minerals (inside the cell) become depleted. However, blood levels of these minerals may remain normal.
When foods or fluids are reintroduced, there is an increase in glucose and insulin. Increased insulin triggers the making (synthesis) of glycogen, fat and protein. These processes require minerals, the same minerals that, as discussed above, are depleted inside the cell during fasting.
Minerals such as phosphate, magnesium, and potassium are already depleted, but once glucose is introduced to the body, there is a high demand for them. Here’s a summary of what occurs during re-feeding:
- Glucose levels in the blood increase, which increases insulin
- Insulin triggers glycogen, fat and protein synthesis
- Phosphate and thiamine (a B vitamin) are used rapidly because they are essential for glucose metabolism
- Insulin stimulates the absorption of potassium and glucose into the cell
- Magnesium and phosphate are taken into the cell, followed by water
- All of the above mechanisms lead to a decrease in blood levels of phosphate, potassium and magnesium (which were already depleted)
The symptoms of re-feeding syndrome occur as a result of the rapid change and electrolyte deficiencies.
Who’s at Risk?
The following is a list of individuals who are at higher risk for experiencing re-feeding syndrome (1):
People who have
- Fasted longer than than 5 days
- Anorexia nervosa
- Inflammatory bowel disease or celiac disease (due to reduced nutrition absorption)
- Cancer or recent surgery (due to high metabolic demands)
- Chronically undernourished
- Uncontrolled diabetes (due to electrolyte depletion)
- Chronic use of antacids (due to magnesium and phosphate depletion)
- Chronic use of diuretics (due to electrolyte depletion)
- A BMI less than 18.5
- Unintentional weight loss (10-15%) in 3-6 months
- Low levels of potassium, phosphate or magnesium before re-feeding
If you suspect you could be at risk for re-feeding syndrome, please consult your doctor for proper monitoring. This is can be a fatal complication and is not something to experiment with alone.
If you are clear from the high risk factors, the two biggest factors for preventing re-feeding syndrome are:
- Adequate hydration with electrolytes
- Slow reintroduction of food
In the 131 Method, we state the importance of electrolytes numerous times. We include a special handout on this topic as well as an “Electrolyte Drink.” For some people, additional supplementation is necessary.
There are many lessons on proper food reintroduction as well! Be sure to take things nice and slow! Don’t reintroduce with a bunch of processed carbs. Not only is that a huge hit of glucose to your system, but it also lacks all of those important minerals in which you might be deficient.
This article is not meant to scare you away from fasting! It’s meant to educate you! We believe it’s important to know your risks, and re-feeding syndrome is one reason we don’t recommend jumping into a seven day fast without proper prep and education. As you’ve learned in the 131 Method, education and proper prep is essential for optimal wellness. We’re so proud of you for taking care of your body the safe way! Major bonus points to you.