GI Issues & Disordered Eating

Gastrointestinal (GI) symptoms are one of the most common side effects of an eating disorder or disordered eating. Many people can find these symptoms confusing or unsettling in their recovery, particularly because wellness culture often advocates for the avoidance of various foods to deal with these symptoms.

Contrary to popular belief, removing lots of foods and food groups from the diet can actually worsen gut symptoms. This is why it’s very important to see a health professional before removing foods. Popularly promoted intolerance tests including IgG tests are poorly backed by science and will likely show you a long list of foods you ate recently. If you are worried about an allergy or intolerance it is always best to work with your doctor and nutrition professional.

Many GI issues are caused (or exacerbated) by restrictive eating, malnutrition and under-use of the GI tract (digestive system). Some of the most common symptoms can include;

  • Bloating
  • Constipation
  • Diarrhoea
  • Flatulence (wind)
  • Abdominal (tummy) pain
  • Fullness after eating relatively small amounts (aka early satiety)
  • Dysphagia (difficulty swallowing)

The sponge metaphor
‘I like to think about a sponge that hasn’t been used in a while. It’s really hard and has dried out. It almost feels like a rock. When you have this hard dry sponge and you put water on it, at first the water just trickles off and doesn’t get absorbed. However, if you consistently and gently put water on the sponge, it starts to become soft, fills up and comes back to life.

At the beginning of recovery, digestion may feel horrible with some pain, bloating and discomfort. However, with the consistency of regular eating and other ways to support the digestive tract it can become soft and comfortable again.’

Marci Evans, RD


Why do eating disorders and disordered eating cause GI issues?
When the brain detects that the body is not receiving enough energy due to restrictive eating, it can’t tell the difference between a self-imposed diet, an eating disorder or famine – it responds to all as if the body is going through a period of starvation. As part of its survival mechanism to help protect the body, the brain will slow the metabolism (all the processes
within the body which require energy).


The brain will want to expend as little energy as possible, which includes energy spent on the smooth muscle of the digestive tract, leading to gastroparesis (delayed gastric emptying) and constipation (see more below) in some folks. Slowed metabolism also means that fewer enzymes and hormones are produced (including appetite and digestive hormones) which
slows digestion down further. In a “normal” digestive tract, the stomach naturally relaxes and expands in a process called accommodation which helps the stomach to take in enough energy and nutrients to meet our needs. In restrictive eating, this process can be compromised so the stomach can feel more sensitive and uncomfortable. It may also result in early satiety which may be an evolutionary mechanism to prevent us from feeling too hungry in periods of famine when no food was available.


Chronic restriction can lead to the muscles of the small and large intestines wasting away due to under-use which means that food takes longer to travel through the digestive tract. This slowing of the digestive process helps to maximise time for digestion and absorption as the body does not want to waste any precious nutrition. Unfortunately, it can lead to stomach
aches, bloating and wind. Normal digestion takes approximately 1.5 hours, however an undernourished body (which can happen at any weight and body size) can take up to 5 hours to digest a meal.


The nervous system may also play a role. Our enteric nervous system or “2nd brain” is actually located in the gut. When we are experiencing physical or psychological stress, our sympathetic nervous system or “fight or flight” is activated. In evolutionary times this threat may have been running away from a lion. As such we get blood flow diverted to our lungs, heart and extremities. Think increase in breathing and heart rate to literally help you run away. At the same time, blood may be diverted away from the digestive tract and reproductive system. Experiencing an eating disorder comes with many physical and
psychological stressors on the body. If we are feeling very anxious about a particular meal for example, we may trigger this “fight or flight” response. As blood flow is moving away from the gut, this may also result in some untoward digestive symptoms.


Purging behaviours such as vomiting and misusing laxatives can also have an impact on digestion. Frequent vomiting can interfere with normal digestion and the rhythm of the GI tract. Whilst misusing laxatives can cause loss of intestinal muscle tone, bloating, gas, pain, appearance of mucus and blood in stools (poo), and, in severe cases, incontinence of faeces and paralysis of the bowel. Most of these symptoms and side effects are reversible after stopping laxatives, which is why it’s important to stop using them and try not to self-medicate using them as this tends to maintain the symptoms associated with misuse of laxatives. (You might be using laxatives for a medical reason as directed by your doctor. In these cases, it’s important to chat with your doctor and any other relevant health care professionals if you have any worries or concerns).

Below, I’ve summarised a couple of the most common gastrointestinal issues that can occur with an eating disorder/disordered eating or are working through recovery.

Gastroparesis
Gastroparesis refers to the delayed emptying of gastric (stomach) contents into the small intestine. Symptoms tend to include post-meal fullness, early satiety (feeling full after eating a relatively small amount of food), nausea (with or without vomiting) and mild upper abdominal pain. Symptoms might also tend to worsen as the day progresses.

Typically when you eat a meal the stomach expands to act as a reservoir and starts digesting the food using wave-like motions (a process called peristalsis) to move food around and eventually into the small intestine. When the body is under-nourished, it doesn’t want to use any extra energy on movement of any muscle, including the smooth muscle of the digestive system, meaning that the process of peristalsis and gastric emptying slows down. It’s important to note that gastroparesis can occur in the context of significant weight loss at any body size (BMI does not need to be ‘underweight’ for this to occur).

Constipation
Constipation includes straining to open one’s bowels, having lumpy or hard stools (poo), feeling like you haven’t fully emptied your bowels (also known as incomplete evacuation), sensation of stool obstruction (also called impaction), needing to assist removal of stool with a finger, or having fewer than 3 bowel movements/week.

When the brain detects starvation or restricted food intake, it doesn’t want to waste any energy in moving any part of the digestive system (similar to the case of gastroparesis), meaning that the large intestine (colon) also slows down.

Inadequate & irregular food intake also directly affects bowel function as the bowel requires an adequate amount of waste in it in order to empty. This means that we need enough going in at one end for anything to come out at the other end! Again, constipation seems to occur with food restriction and weight loss, regardless of body size.

Treating/improving GI problems
These GI symptoms tend to improve when food intake is normalised – i.e. eating regularly, and including all foods groups (particularly grains and potato foods). It can take some time for the GI system to recover to normal functioning.

If you’re working towards increasing frequency, quantity and/or variety of food, it’s normal to get some GI discomfort in the short term. You haven’t eaten “too much” or the “wrong” thing. The following tips might be helpful in managing some GI discomfort as part of ED recovery/ nutritional rehabilitation:
● Try sitting comfortably with a hot water bottle or wheat bag on your tummy
● Use your compassion statements/ recovery-focused mantras to remind yourself to talk to yourself with compassion and kindness
● Try using distraction techniques such as doing a jigsaw puzzle, phoning or texting a pal, watching a favourite film etc.
● Try gently rubbing your tummy in a clockwise motion for 10-20 mins to help soothe some of the discomfort and aid digestion.
● Being cautious with use of diet fizzy drinks, chewing gum and artificial sweeteners which can exacerbate untowards gut symptoms.
● Trying mindfulness practices like meditation or deep breathing which can help calm the nervous system and help blood flow to the digestive tract.

To help with constipation, aiming to maintain an adequate fluid intake each day can be helpful – for most people this is around 1.5 – 2 litres. (Note: It’s important not to drink vast amounts of fluid as over-hydration can cause dangerous shifts in electrolytes, as well as being an ED behaviour for some folks).
In those without an eating disorder or restrictive eating, increasing the intake of fibre is usually recommended for constipation. BUT when constipation is a result of slowed metabolism, high fibre diets don’t tend to improve things – in fact they can cause further bloating and discomfort. Things tend to improve with a lower fibre diet and nutritional rehabilitation (regular eating and eating enough). As metabolism speeds up and constipation becomes less of an issue, more fibre can be reintroduced slowly, if necessary or desired. It might be helpful to check in with your dietitian or nutritionist about this.

Further Reading & Sources

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