Something you need to be aware of and informed about when you are diving into the process of overcoming a restrictive eating disorder (or even toe-dipping) is refeeding syndrome and the risks that it can pose. This post is not to scare anyone or to speak to any eating disorders out there who use it to convince you, "See, eating more is too risky—stick to your safe foods and amounts!". That is not the idea of this post. You already know that I advocate abstinence from all restrictive eating and behaviours to overcome a restrictive eating disorder. However, during the first week or two of eating more, there are risks when it comes to going from zero to hero with your intake that you need to consider. And throughout the process, as your body learns to process and cope with more food and is rebuilding and restoring after years of being semi-starved, you will experience other physical effects. I will cover a few of these in this post as well.
For some people, there is a risk of refeeding syndrome in the first few days or couple of weeks of eating more. Although not very common, when it does occur, refeeding syndrome can be dangerous and, in some cases, can result in death. But, as I said, this post is not to frighten you—it is to inform you so you can safely start to eat to all your hunger.
In most cases, refeeding syndrome starts in the first four to seven days when a person who has been malnourished begins to eat more.
There is no clear definition for refeeding syndrome but it’s understood to be a combination of hormonal and metabolic changes that happen in people who are nutritionally debilitated and deemed to be 'fed too fast' (but we will get into this argument later!). Water and electrolyte imbalances can occur, particularly noticed as significant drops in certain electrolytes, of which a reduction in blood phosphate is the most widely recognised diagnostic marker, but drops in potassium, sodium, magnesium, calcium and thiamine can also occur. There are also shifts in blood glucose levels.
What Causes Refeeding Syndrome?
When your body is malnourished and in energy deficit, your insulin levels drop and your glucagon levels rise. Your body then adapts to this using alternate energy sources for essential functions. So, in an energy-balanced body, it will use glucose as the primary energy source but when in energy deficit, it will switch to using fatty acids and amino acids for energy instead which it gets by breaking down fat and muscle tissues.
If your body has been in an energy-deprived state and is then given a large amount of food, your insulin levels will increase which will cause a quick shift of potassium, magnesium and phosphates into the cells. But because your body doesn't have sufficient supplies of these, it can't cope with this sudden shift and the circulating blood is left with very low levels. It is these electrolyte deficiencies that then result in the complications that can occur in refeeding syndrome. You might also experience a rise in blood glucose and a drop in thiamine (vitamin B1).
What Are the Signs & Symptoms of Refeeding Syndrome?
A range of symptoms can occur as a result of refeeding syndrome. Many people will get symptoms that result from mild refeeding syndrome and blood electrolyte changes that their body copes with. As I said above though, in rare cases, refeeding syndrome can be more serious.
Signs and symptoms of refeeding syndrome to be aware of are:
abnormal heart rhythms
oedema (water retention)
nausea and vomiting
a drop in blood pressure or heart rate
muscle spasms or cramps
shortness of breath
balance or coordination difficulties
a rise in blood sugars
Of course, some of these, such as low heart rate, low blood pressure, being light-headed or balance difficulties can also be symptoms of semi-starvation and energy deficit. So, in the first days or week of eating more, notice any changes in your symptoms and if you have concerns, speak to a health professional.
Who is Most at Risk of Refeeding Syndrome?
Refeeding syndrome can occur in anyone who has been malnourished and then starts to refeed. But some factors that would put someone at a higher level of risk are:
Recent weight loss of more than 10% body weight
Severely restricted food intake in the past 7-14 days
A person with signs of starvation syndrome, commonly seen in people with restrictive eating disorders (please see my book Addicted to Energy Deficit for more on this)
Frequent self-induced vomiting
Chronic alcohol use
Chronic overuse of laxatives or diuretics
And please note that not only people underweight by BMI chart are at risk. People with a BMI in the overweight or obese categories can also develop refeeding syndrome and are at risk of the same consequences.
Anyone who has a very low daily intake, has sustained significant weight loss in the past six months, purges through vomiting regularly or abuses laxatives or diuretics should be more cautious in the first week or two of increasing their intake. Refeeding syndrome is less likely in someone whose weight has been stable in recent months (even if at a point significantly below their set point) and in people who still eat regularly, even though that intake is restrictive.
I'd advise anyone overcoming a restrictive eating disorder to request blood test monitoring in the first weeks or even month or two where they can, but this is not just recommended but critical if you consider yourself to fall into a moderate or high-risk category of developing refeeding syndrome. Monitoring should involve regular blood tests to check phosphate, potassium, magnesium and kidney function in the first few weeks of increasing energy intake. Heart tracings are also advisable.
How to Prevent Refeeding Syndrome?
Firstly, be aware of the risks and how high a risk you would perceive yourself to be. If you are uncertain, speak to a health professional with experience in this area (but be aware that many general practitioners won't be overly familiar with refeeding risks as it isn't common).
Some people are prescribed supplements of multivitamins or thiamine to help reduce the risks of refeeding syndrome. The jury is still out in the research about how beneficial this is. It's not always possible to prevent refeeding syndrome from occurring, but recognising the signs and symptoms early and being monitored (as advised above) will help to ensure that if it happens, it’s treated in time.
Low & Slow with Refeeding?
Traditionally, the advice has been to 'start low and go slow' when reintroducing nutrition to someone at risk of refeeding syndrome, but some experts now doubt this approach. Using a slow approach to refeeding someone after a period of malnutrition actually carries a risk of underfeeding syndrome, where the individual loses weight because refeeding is too cautious, resulting in further complications from malnutrition. Research now demonstrates that more rapid refeeding can be safe, assuming phosphate levels are monitored. It's advised though that your diet in the first week should ideally include less refined sugars (although these are great for the process beyond this!) and adequate levels of proteins and fats.
Please don't use the risk of refeeding syndrome as a reason not to increase your intake or to continue to restrict longer than necessary. IF you are at risk of refeeding syndrome, the risks generally pass after 1-2 weeks of initially eating more so this is a short-term risk and then not an excuse to not abstain from all your restrictive eating beyond any potential risk period!
Oedema & Weight Gain
For most people, the complications of refeeding will be mentally and physically uncomfortable but won't put them at medical risk. One common complication to cause mental and physical discomfort is oedema (or fluid retention).
The oedema that can set in when you abstain from restriction can reinforce the anxiety-based thoughts that eating just a fraction more makes you gain weight overnight. Fluid retention results from changes in your blood sodium levels and glycogen stores because of eating more, as well as rehydration of your tissues because many who are malnourished are also dehydrated. This gain in what is commonly referred to as water weight can cause a bigger jump in the numbers on your scales, seemingly overnight, when you do start to eat more. If you experience this and you are weighing yourself or being weighed, remember that this rise is due to fluid shifts and not true weight change. The swelling and bloating—commonly seen in the ankles, around the eyes and face and the midsection (although other body areas can also be affected)—will gradually improve, but this can take several weeks. Just keep eating and trust your body to do what it needs to do to heal and restore.
Another post is coming soon about more digestive side effects that you can experience. But just to say now that abdominal discomfort and 'tummy' troubles are common when you start to eat more.
When your body has been energy deprived, it puts a low priority on maintaining the intestinal system as it preserves energy supplies to keep more vital organs functioning. Therefore, your stomach and intestines need vital repairs before they can work optimally for you. But this is a chicken-and-egg situation—to get the energy into your body to do those repairs, there needs to be extra food intake into a stomach that can't yet digest at its best. Therefore, as you begin to eat more, your stomach will have slow emptying, which can lead to nausea, stomach cramps, bloating, wind and constipation, as well as feelings of physical fullness on what are still small amounts of food. You need to push past this and keep eating to give your body the energy it needs. At this stage, you are likely to experience a confusing mix of new hunger and excessive fullness. Plus, anxiety and stress related to the process of overcoming the eating disorder are potential appetite suppressants and can exacerbate abdominal symptoms such as nausea and cramps. Expect tummy discomfort and symptoms. Once again, trust that eating and abstaining from restriction will, in time, allow your body to repair and heal your digestive system so that tummy troubles have much less of an impact on your life.
**The information here is taken from my newly available book, 'Addicted to Energy Deficit - A Neuroscience Based Guide to Restrictive Eating Disorders' which you can buy now!**
If you like to listen, as well as (or instead of read!) then this blog post is the transcript of a podcast episode which you will find on my podcast series,
available on this website, all mainstream podcast platforms and on YouTube.