Constipation in Individuals with Eating Disorders 

Gastrointestinal (GI) symptoms, including constipation, are a common symptom of disordered eating and common in people with eating disorders. Constipation can be defined as difficulty passing stools, infrequent bowel movements (less than three times per week for adults), and/or stools that are hard, dry, or lumpy (type 1 or 2 on the Bristol stool chart), often accompanied by a feeling of incomplete evacuation, straining, or rectal discomfort during bowel movements. It can also be accompanied by the presence of symptoms such as abdominal pain and discomfort, and bloating. 

Constipation can occur due to:  

• Food restriction leading to delayed gastric emptying and longer transit time of the entire GI system (Wiklund et al, 2021; Norris et al., 2016).  

• Electrolyte disturbances (especially hypokalemia) and dehydration, due to self-induced vomiting, laxative, or diuretic misuse (Hetterich et al., 2019; Zipfel et al., 2006).  

• Discontinuing the use of laxatives after prolonged use and the large intestine having become functionally dependent on them (Mehler, 2011).  

• An increased delivery and stool volume due to bingeing, leading to colon discomfort and constipation (Cremonini et al., 2009).  

• Use of eating disorder behaviours such as vomiting, laxative misuse, and excessive exercise causing an increase in abnormal intra-abdominal pressure and leading to structural damage of pelvic floor muscles (Santonicola et al, 2019; Silvernale et al, 2020).  

• Weakness of the smooth muscle of the bowel due to the effects of semi-starvation and malnutrition (Bern et al., 2016). 

• Decreased fibre intake, or conversely, inclusion of too much fibre (particularly insoluble fibre such as wholegrains, some fruit and vegetables, and nuts and seeds) (Chey, Eswaran & Muir, 2021). 

Treatment Plan  

Some tips on how to manage constipation through dietary changes as a first-line treatment include: 

• Encourage regular eating (Heathcote & Carey, 2025). 

• Include fats at meals as this stimulates the gastro-colic reflex (which increases the urge to pass stools) (Rao et al., 2000; Dorfman et al., 2022). 

• Encourage adequate hydration (Anti et al., 1998; Sadler et al., 2022; Australian Government Department of Health, 2019). 

• Consider adding kiwifruit or prunes as these foods have evidence to increase stool frequency, improve stool consistency, and decrease straining (Chey et al., 2021; Bayer et al., 2022; Dimidi, 2025). 

• Consider adding foods with soluble fibre e.g. oats, white grains (rice, pasta, couscous), starchy cooked vegetables (potato, sweet potato, pumpkin), legumes, fruit with no skin (apple, citrus, banana), instead of insoluble fibre e.g. wholegrains, fruit with skin on, leafy vegetables (broccoli, brussel sprouts, spinach), and nuts and seeds, as soluble fibre can soften stools, increase stool frequency. and are better tolerated generally (Chey, Eswaran & Muir, 2021) 

• Consider use of soluble and viscous fibre supplements, such as psyllium (Dimidi, 2025). 

• Consider using probiotic strains specifically for constipation (Agrawal et al., 2009; Guyonnet et al., 2007; Eskesen et al., 2015) that are found in some probiotic yoghurts e.g. Activia Probiotics, Vaalia Probiotic or Farmers Union Protein & Prebiotics. 

Some other tips to help manage constipation include:  

• Promote weight restoration as being a low weight affects the functioning of the gastrointestinal tract (Heathcote & Carey, 2025; Bluemel et al., 2017). 

• Develop a regular bathroom routine – make time 10-30min after the first meal when the gastro-colic reflex is most active (Malone, 2023), avoid straining and use diaphragmatic breathing, use a step or stool so that knees are elevated above hips while leaning forward to ensure the colon is in a position that allows for ease of evacuation and improves completeness of evacuation.  

• Support reduction / cessation of disordered eating behaviours (restricting, bingeing, vomiting, laxative abuse, excessive exercise) to restore healthy gut motility, enzyme production, and gut microbiota (Bluemel et al., 2017; Forney et al., 2016). 

• Stimulant laxatives e.g. Dulcolax, Senokot, Coloxyl with Senna, are not recommended, as not only can they also cause painful cramping, but long-term can cause dependency and damage to colonic nerve cells (Mehler et al., 2015). The preferred laxative, if required, are osmotic laxatives (Mehler & Krantz, 2003), which work by drawing water into the intestines to soften stools and increase stool volume making it easier to pass e.g. Osmolax, Movicol, or Lactulose  

• Pelvic floor physiotherapist can help identify and treat pelvic floor dysfunction (American Gastroenterological Association, 2023; LaCross et al., 2022) 

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