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April 13, 2017

Why am I losing weight? | Unexplained weight loss causes

344508682_e7c209bf6e_m.jpgThe topic of weight and weight loss is complicated and can cause a lot of debate amongst social groups. Some people want to lose weight, or need to lose weight for health reasons, whilst others struggle to put the pounds on or maintain their weight at a healthy level. Most of these attempts at controlling weight are deliberate and require a concerted effort in changing diet and lifestyle, but occasionally, changes in weight can happen with seemingly no change in energy intake or output. Significant unexplained weight loss can sometimes be a sign of an underlying illness which you may be completely unaware of, and as such should be monitored and explored should the weight loss continue.

Unintentional weight loss is a decrease in body weight that is not voluntary. Weight loss will occur with inadequate food intake, malabsorption, increased metabolism, or a combination of these factors. If you haven’t been trying to lose weight or exercising more than normal, but you have noticed a decrease in your weight, a trip to the doctor is advisable. You can check out your symptoms on the Isabel Symptom Checker to research possible causes so you can have a fruitful discussion with your healthcare professional.

How much weight loss is a concern?

Body weight can fluctuate according to the time of year or even the time of month for women, and sometimes your weight on the scales can vary as much as 2-3lbs throughout the day. This is mostly due to fluid retention and your body’s normal bodily functions, and a good way to cancel out these natural fluctuations is to get an average of your weight from each day that week.

Stress and changes in your life can sometimes affect your weight. Losing weight after a traumatic event such as a divorce or bereavement is completely understandable for example, as your body uses more energy to grieve and recover from the event or change. In these cases, once the physical or emotional health issues have been resolved, your appetite increases and/or your weight returns to its previous state.

It is considered that losing more than 5% of your normal body weight in a 6-12 month period is a cause for concern. For example, weighing 140lbs in May, and dropping to 133lbs by November, with no change in diet or lifestyle would suggest something is affecting your body, and you should arrange an appointment with your healthcare provider to try and find the cause.

Your doctor will take a full history and possibly carry out a physical examination with some lab tests, to try to work out the cause of your weight loss. They might also want to know if you’re suffering from any of the following which often accompany weight loss:

  • Unusual tiredness
  • An increase in illnesses and infections
  • Loss of appetite
  • A change in toilet habits.

Sometimes, if the basic evaluation is negative you may just need a special diet to prevent further weight loss or to regain lost pounds, and then you can monitor your weight closely to see if the weight loss continues or restarts after the diet.

What else could be causing my weight loss?

Weight loss is a very nonspecific and broad symptom and sometimes unexplained weight loss be indicative of a more serious underlying pathology. We’ve listed some of the more common causes of unintentional weight loss in this post, to start you off with your research.


While Depression can be triggered by an adverse event, it is not the same as the normal state of sadness you might feel following the bereavement or trauma mentioned above. Depression is an illness where sufferers feel persistently down for weeks or months. Other symptoms in addition to weight loss include:

  • irritability
  • lack of motivation
  • indecision
  • suicidal thoughts
  • constipation
  • lack of energ
  • loss of libido
  • insomnia
  • avoiding contact with friends
  • neglecting hobbies.

If your moods tie in with the above, and the symptoms have persisted for more than 2 weeks, it’s important to see your doctor. Many people feel embarrassed about seeking help but depression is becoming increasingly common, affecting 1 in 10 people.

Overactive Thyroid (Hyperthyroidism)

This is when your thyroid gland, found at the front of your neck, produces too much of the thyroid hormone. An overactive thyroid can cause a wide range of symptoms in addition to weight loss, including:

  • insomnia
  • mood swings
  • persistent tiredness
  • swelling in your neck
  • irritability.

The condition tends to affect women more than men, usually between 20-40 years of age. If left untreated, Hyperthyroidism can lead to further serious problems: a simple blood test can provide the answer to whether or not you need treatment.


In the majority of cancer cases, other symptoms will develop before you notice any weight loss, which is caused in part by the increased activity of cancer cells in the body which require nutrition. Signs and symptoms vary according to the type of cancer but the more common symptoms to look out for, in addition to weight loss include:

  • fatigue
  • unexplained muscle or joint pain
  • a lump under the skin
  • changes in bowel and bladder habits
  • skin changes including moles
  • hoarseness or a persistent cough
  • unexplained bleeding.

All of these symptoms are often caused by other non-cancerous illnesses but it’s important to visit your doctor as soon as you become concerned to get a proper diagnosis.


There are two main types of Diabetes: types 1 and 2. Type 2 is far more common and can take years before it is properly diagnosed, whereas Type 1 can develop very quickly over weeks or even days, and usually happens in childhood. Diabetes is a life-long condition which causes the sufferer’s blood sugar levels to become too high. In addition to weight loss, the other key symptoms to look out for are:

  • excessive thirst
  • passing large amounts of urine
  • tiredness
  • frequent episodes of thrush
  • slow healing wounds.

The weight loss is partly due to the sugar (glucose) that is passed out with the urine. The sooner Diabetes is diagnosed by a doctor the better as it will get progressively worse and harder to manage if left untreated.

Alcohol and Substance Abuse

Excessive alcohol and/or drug use often leads to weight loss, simply as a result of the sufferer not looking after themselves properly. Friends and family may notice the weight loss first without being aware there’s an underlying cause of addiction. Classic symptoms vary, depending on the substance, but can include, in addition to weight loss:

  • sickness due to withdrawal
  • trembling
  • overwhelming cravings
  • a general unwell look e.g. grey in colour or gaunt in the face
  • insomnia
  • neglect of other interests
  • spending more time on activities where alcohol or drugs are easily available.

If you are concerned about your drinking or drug habits, or that of someone you know, you should consult a doctor about the best ways of tackling addiction. About 1 in 3 sufferers can cure their addiction without professional help. Indeed, simply accepting you might have a problem and seeking help for it is, for many, the biggest step to cutting back. Others may prefer to seek advice from counsellors or their doctor to stop their addiction.

Diseases of the Gut

Given that abdominal pain, cramping and heartburn are common symptoms of gut diseases such as Inflammatory Bowel Disease, Stomach Ulcers and Coeliac Disease, it’s no surprise that weight loss is a frequent side effect as eating becomes harder and more painful. Other symptoms could include:

  • diarrhoea
  • bloating
  • indigestion
  • tiredness.

The extent of each symptom can vary enormously from patient to patient and condition, but medical help should definitely be sought to establish whether gut disease is the cause.

Nick Robinson and Lung Cancer

The illnesses mentioned above are just a handful of the many causes of unexplained weight loss, some more serious than others. Either way, it’s best to seek medical help and use the Isabel Symptom Checker to research possible diagnoses. The query below reveals the cause of the symptoms which affected the BBC News reporter, Nick Robinson who, having suffered from a persistent cough was referred to a specialist. It was only by chance that Robinson mentioned he’d bought himself a new suit, having unintentionally gone down a suit size.


Luckily for him, the consultant made the connection between his cough and weight loss and diagnosed lung cancer in time for successful treatment. In cases similar to that of Nick Robinson, it is important to think about the causes of unexplained weight loss before simply accepting, or even celebrating, the change. Use the Isabel Symptom Checker to input all your symptoms and research the results to discuss with your healthcare provider.



Image Attribution:
"measuring tape" (CC BY-NC-ND 2.0) by Madame Etepetete


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