So much attention is focused on weight gain and obesity as a driver of ill health. But unexplained weight loss – or an inability to get up to a healthy weight – can also be a symptom of various conditions.
Common causes include gastric problems, such as ulcers or Crohn’s disease. Cancer Research UK also says losing weight can be a general symptom of cancer, most commonly in lung cancer or those related to the digestive system.
‘As doctors, we know that if someone is losing weight without trying to, or for no obvious reason, then it is a red flag,’ says Dr Rachel Ainley, a GP and head of research at Crohn’s and Colitis UK. But the challenge then is to work out why – unexplained weight loss can have many causes.’
This can cause confusionwith diagnosis, especially with gastric conditions.
‘One of the biggest issues when it comes to getting a diagnosis for these conditions is that so many have similar symptoms,’ says Dr Ainley (the charity has recently joined forces with other health organisations to create an information website to help patients, whatsupwithmygut.org.uk).
We spoke to five people about their weight loss and the very different health problems that caused it, while experts explain what to look for…
‘Stress’ of moving. It was a thyroid problem
Eleanor London’s weight loss was put down to stress before blood tests revealed that she had hyperthyroidism
Eleanor London, 70, a retired NHS manager and mother of two, lives in the Vale of Glamorgan with husband John, 74, also retired. She says:
I’ve always gone to the gym and kept healthy – I weighed 9st 11lb for years (I’m 5ft 4in) – but in summer 2018 I stepped on the scales and I was 9st 5lb.
I hadn’t been dieting, so I put it down to the stress of us moving house and carrying heavy boxes around. Around that time I also noticed I’d tire easily and my heart rate was faster than usual, but told myself it was just the heat and ignored it.
I weighed myself again a few days later and I was 9st 1lb – I’d lost 10lb in a couple of weeks without trying. When I fell below 9st shortly after, I really started to worry.
My GP sent me for blood tests –and the next day she called me to say I had hyperthyroidism, an overactive thyroid.
It meant I produced more thyroid hormone than normal and this in turn increased my metabolism and caused the sudden weight loss.
I was referred to an endocrinologist but in the meantime my GP prescribed carbimazole, which cuts the amount of thyroid hormones you produce, as well as beta blockers for my heart – I was told a racing heart is a classic symptom of an overactive thyroid. Within months I had more energy and started gaining weight.
I saw an endocrinologist after two months – tests showed my hyperthyroidism was caused by Graves’ disease, where your immune system attacks the thyroid gland, pushing it into overdrive.
My symptoms are now under control, but I’ll take the medication for life. It makes me a bit fatigued, so I have to pace myself, but I still exercise regularly.
I now weigh 10st 7lb – the heaviest I have ever been since pregnancy 30 years ago! But I am glad – I’d rather put weight on than be losing it the way I was.
Expert comment: ‘We need thyroid hormones to regulate our metabolism – but too much results in this speeding up,’ says Kristien Boelaert, a professor of endocrinology at the University of Birmingham.
‘Many patients report significant weight loss despite an increased appetite – and the condition can also cause a faster (sometimes irregular) heart rate, shaking of the hands, tiredness and diarrhoea, as it hastens transit time. Graves’ disease is the most common underlying cause of an overactive thyroid.
‘It affects up to 3 per cent of women, and can often be missed or confused for other conditions such as menopause.’
Blamed Covid. It was… type 1 diabetes
Dicky Broadhurst felt run down after Christmas and was later diagnosed with type 1 diabetes
Dicky Broadhurst, 42, runs the Present King gift-finding business and lives in Milford-on-Sea, Hampshire, with his wife and two children, aged four and five. He says:
As Christmas 2021 approached both my wife and I caught Covid and were so ill we spent most of the time tag-teaming between childcare and sleeping.
I was usually 13st – I’m 5ft 9in – but a few days after the illness I weighed myself and I was 12st.
The first thing I did was pat myself on the back: like most people I thought losing weight was a positive thing.
I was still very run down afterwards so the doctor gave me a blood test. I had to wait until after Christmas for the results – we went away for New Year’s and I weighed myself again when we got home: down to 11st 6lb – I’d lost a stone and a half in days despite eating and drinking more. I was also incredibly thirsty, especially for sugary drinks.
The GP told me the blood test results showed I had type 1 diabetes, a condition I thought only children got.
He explained my glucose levels were off the charts, which is why I was so thirsty and it had caused the weight loss.
I started on insulin within hours. I can now function close to how I did before. My weight is normal and I am feeling well.
Expert comment: Dr David Cavan, a consultant endocrinologist at University Hospitals Dorset, says: ‘Insulin drives glucose [from the food we eat] into the cells, where it’s stored as energy. But in type 1 diabetes, the body is not able to produce insulin.
‘It starts burning fat and muscle for energy – so patients lose weight – and tries to get rid of glucose via urine, so you need the bathroom more, leading to dehydration and further weight loss.
Type 1 diabetes is caused by an autoimmune reaction that destroys the insulin-producing cells in the pancreas – it’s generally seen in children and young adults, but it can occur at any age. ‘We observed an increase in type 1 diabetes diagnoses during the pandemic.
‘It’s not unusual that type 1 diabetes is diagnosed following a viral infection, possibly as a result of a “faulty” immune response to the infection.’
Friends noticed it first. It was cancer
Mez Solanki’s weight loss, spotted by a friend, was a sign of non-Hodgkin lymphoma
Mez Solanki, 45, a cyber security expert, lives in Milton Keynes, Buckinghamshire, with wife Jigisha, 40, a service delivery manager, and their children, aged four and one. He says:
In summer 2021, I went to a wedding and saw lots of old friends. Several commented on how much weight I’d lost, which was odd as I hadn’t been trying.
One friend took me aside and said very seriously: ‘You should see a doctor. You shouldn’t be losing weight without trying.’
When I got home I hopped on the scales. I usually weigh 11st 8lb (I’m 5ft 8in), but sure enough, I’d lost around a stone and a quarter (8kg) in six months.
Over the next few days I started to wonder whether it was linked to other symptoms I’d started to have recently: I was waking up drenched in sweat and felt regularly fatigued.
Then I got abdominal pains, so I contacted the GP – but multiple blood tests and a colonoscopy came back clear.
Meanwhile, I was still losing weight and becoming increasingly unwell. I couldn’t stand up for more than three seconds without feeling exhausted.
I used my private health insurance to see a specialist, who ran more blood tests as well as scans – then a biopsy of a growth spotted in my lower back. This confirmed I had non-Hodgkin lymphoma, a blood cancer.
It was stage 4, very advanced, and was the reason behind my weight loss and other symptoms. I had six months of chemotherapy, but thankfully I am still in remission.
I still have after-effects of chemo such as poor immunity, but otherwise I’ve regained some weight (I’m now 12-and a-half-stone), am able to stand again and life is good.
Expert comment: ‘Non-Hodgkin lymphoma tumours burn a lot of calories, but at the same time may suppress a person’s appetite – inevitably this leads to weight loss as people just can’t get enough calories in,’ explains Dr Rob Lown, a consultant haematologist at University Hospital Southampton.
Dr Rachel Orritt, health information manager at Cancer Research UK, adds: ‘If you’re losing weight without trying to, or you’ve noticed anything else that’s not normal for you, talk to your doctor.
‘Weight loss can be caused by lots of other conditions, too, but if it is cancer, getting a diagnosis means treatment can start, which can make all the difference.’
Busy family life… it was anxiety
Christine was prescribed antidepressants and therapy following her weight loss with anxiety
Christine Elliot, 61, is a carer and mother of five. She lives in Lincolnshire with her husband. She says:
I spent most of my life thin and unwell and often wondered what the cause was. It turned out it was my anxiety.
As a child I suffered a lot from anxiety, and no matter what I ate, I was slim, running on nervous energy. When I met my husband and felt settled for the first time, I slowly gained weight and the anxiety abated. But when my daughters were very young, I went back to college and I began to lose weight, despite eating the same amount. At my lowest I dropped from nearly 9st to 6st 7lb; I am 5ft 3in.
My family often mentioned how thin I was, but I put it down to running around after young children.
I was often ill and seemed to catch everything going, but never saw the GP. However, I finally did ask him whether my anxiety could be the problem: he referred me to a counsellor who officially diagnosed me, and explained that anxiety could cause weight loss.
I was prescribed antidepressants, I tried talking therapy as well as a mix of exercise and mindfulness to see me through the anxious attacks. Gradually the weight came back without making any changes in my diet – now, after many years of being too thin, I’m a healthy 9st 2lb.
Expert comment: Dr Elena Touroni, a consultant psychologist and co-founder of The Chelsea Psychology Clinic in London, says: ‘Anxiety and stress trigger the release of hormones such as cortisol and adrenaline, which can suppress appetite, speed up metabolism, and cause digestive issues such as nausea or an upset stomach, all of which can lead to unintentional weight loss. Additionally, people experiencing anxiety may develop nervous habits such as fidgeting or pacing. Therapy, lifestyle changes, and sometimes medication can help.’
