What's the link between diabetes and eating disorders?

Lockdown has increased pressure on people affected by, or recovering from, disordered eating. In June, leading UK charity Beat reported a 73% increase in calls.

Research shows that people with type 1 or 2 diabetes are more likely to experience these conditions. A review of over 300 patients found that 6.5-9% of patients with type 2 diabetes had an eating disorder (ED). In the general population, it's estimated that ED affects up to 6.4% of adults. According to the review, binge eating disorder was the most prevalent. 

Eating disorders are far more common in people with type 1 diabetes than in people without diabetes. One review estimated that EDs were seen more than twice as frequently amongst girls and women with type 1.

Lockdown adds stress too, highlights Dan Howarth, head of care at the charity Diabetes UK.

"It's a worrying time for many of us, particularly those with diabetes who are more likely to become seriously ill if they develop COVID-19," he says. "During lockdown, people with diabetes may also have concerns about leaving the house for appointments, or have difficulty accessing appointments remotely."

Why diabetes matters

Sadie*, 50, was diagnosed with type 1 diabetes four years ago. She had had bulimia and recovered, but experienced a relapse after getting her diagnosis.

Before getting diagnosed, Sadie had been working hard to lose weight through a combination of healthy eating and exercise. One of the reasons she started to exercise was to prevent type 2 diabetes.

At first, she was proud to see results. But she noticed that the weight was coming off very quickly, and she was getting a very dry mouth and feeling tired all the time. As she became more ill, she also noticed the return of the types of thoughts that she recognised from the eating disorder.

Sadie got a type 1 diabetes diagnosis from her GP and was rushed to hospital. After she was discharged, she tried to cope with the eating disorder on her own for a week or two. It became clear then that she was facing a relapse. A month after her diagnosis she managed to call the diabetes team to explain how the diagnosis had affected her mental health. She was then offered more support, including counselling.

The stigma around eating disorders made it feel difficult to ask for help, she explains. "It felt embarrassing. You don't read about people in their 40s with eating disorders."

Looking back now, she wishes that it had been easier to tell people what was happening. She advises those going through a similar experience to try to tell someone.

Cause and effect

While diabetes and disordered eating aren't linked, each condition increases a person's risk of the other.

In very general terms, diabetes puts people at risk of poor mental health because of the stress it can cause. People with one of the main types of diabetes, type 1 or 2, usually find that diabetes changes their relationship with food. For example, people with diabetes might feel hungry after eating. Most can no longer eat 'intuitively' or eat in the same way as non-diabetic friends and family. Having a difficult relationship with food affects our enjoyment of it and the way we spend time with family or friends.

For some people with diabetes, diagnosis or disordered eating reminds them of a stressful period in life. The daily management of type 1 or 2 diabetes risks creating a cycle of 're-traumatisation' that deepens the link between the illness and memories of that period. The stress of living with diabetes is now recognised by clinicians as 'diabetes distress'.

A particular ED risk for people with diabetes requiring insulin treatment is diabulimia. People with diabulimia reduce their insulin use to control their weight. Although it is not as common as other eating disorders, it is much more dangerous.

Eating disorders can also increase a person's risk of developing type 2 diabetes. Binge eating disorder has been shown to increase insulin resistance and weight gain, both of which are risk factors for type 2.

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Better treatments

Sadie remembers the things that helped her cope after her diagnosis: being paired with an empathetic counsellor, who had a relative with diabetes; her consultant's constructive and non-judgemental approach; and using light exercise, such as going for a run or to the gym, to relax. She is now learning to manage her diabetes and eating disorder, and speaks about her experience to support others and raise awareness.

Dr Marietta Stadler and Amy Harrison are both working on an intervention, STEADY, to prevent ED in type 1 patients. As part of their research they interviewed people like Sadie who can explain what it's like to have type 1 and ED, and what helps them cope.

Harrison, who's a clinical psychologist in London, says: "People talked about type 1 being a kind of relentless 24/7 job. It sensitises the person to cues about eating and weight and shape. Often their weight will fluctuate. They might lose a lot when they're first diagnosed and when they start insulin, it impacts on their weight. This was particularly important for people with a history of disordered eating, depression or anxiety.

"People might get stuck in a vicious cycle where they omit insulin, or overcorrect because they're terrified of their blood sugar going 'out of range'. This cycle is maintained by beliefs that they must look a certain way, or by other people's comments on what they should or shouldn't be eating."

She adds that patients also said how important it became for them to stop judging themselves according to how well (or badly) they managed their weight.

In December 2020, doctors warned that more children, in particular, were being brought for treatment.

But Dr Stadler, an NIHR scientist, is optimistic about the long-term outlook - for example, how new blood sugar 'traces' visualised by continuous glucose monitoring (CGSM) tech will help doctors and patients have better conversations about type 1.

"As a diabetes clinician, I'll find it easier to identify somebody struggling with insulin omission, binge eating attacks, overcorrection of high blood sugar levels and hypos because we'll see them in the 'trace'," she says. "Now in the consultation we can say, 'Shall we look at the trace together?'"

What's next?

Last month two new initiatives launched that promise to improve support for patients with diabetes and disordered eating. Firstly, an intervention called 'FREED' promises young people in England aged up to 25 rapid access via self-referral to specialist NHS treatment for ED. The service has been shown to reduce waiting times and improve outcomes, promising 48-hour responses for first contact. In 2019 a new study recommended screening and early intervention for teenagers with type 1 to prevent disordered eating, and FREED may be able to enact this recommendation.

In the same month, Diabetes UK launched a new training module for healthcare workers about the link between diabetes and mental health. It specifically covers diabetes distress, burnout and disordered eating.

The link between diabetes and chronic mental health problems has been well established. For example, we know that people with diabetes are twice as likely to develop depression than people who don't have it. Soon, researchers will have new ways to break its link to eating disorders.

*name changed.