5 possible reasons for your unexplained weight loss

Experiencing weight loss without trying to drop weight, especially if you’ve been a relatively stable weight throughout your life, can be a worry.

Regardless of what your weight was before, dropping pounds for no apparent reason should be looked into. Luckily, causes of weight loss are usually relatively straightforward.

What causes weight loss?

Losing weight is almost always a case of calories in versus calories out.

If you start taking in fewer calories, you’ll create a calorie deficit in your body. Then, your body will burn into stored energy and you’ll lose weight as a result. You can do this by eating fewer calories than you burn – or expending more energy than you eat.

But a calorie deficit isn’t the full explanation for unexplained weight loss. What if you’re still eating the same way as ever – and your activity levels haven’t changed much either?

Stress

Whereas a little stress can be a good thing – it motivates us and energises us to face responsibilities and tasks – too much stress can have a serious negative effect on your wellbeing. Weight loss can be a common side effect of stress.

The so-called ‘stress hormones’, cortisol and adrenaline, are produced in excess when we’re chronically stressed. Too much of these hormones can bring on a range of physical symptoms such as headaches, muscle tension, chest pain and a rapid heartbeat.¹

Reduction in appetite and trouble digesting food are also common in stressed people, along with increased fidgeting and movement.² Altogether, this leads to weight loss.

A major life change…

Major life changes such as a relationship breakdown, bereavement, divorce or redundancy can cause temporary physical symptoms, and can be a cause of weight loss.³

These changes could even be positive ones, such as a new job, new partner, house move or planning a wedding.

These things can call cause anxiety, which can lead to poor sleep, reduced appetite and digestive issues – all risk factors for unwanted weight loss.

…or minor ones

It’s likely that if you’re losing weight gradually, you’re eating less and moving more without realising it. Small changes can add up to a calorie deficit.

Let’s say you’re embarking on a DIY project which sees you painting several rooms at home. The project will take up every weekend for a month. Painting the walls (and moving furniture out of the way) might burn up to 3000 calories per weekend,⁴ which would see you dropping a few pounds over that month without changing anything else.

Some people have reported weight loss after getting a dog (think of all those walks!)

Have you switched your coffee order? Even something as simple as opting for an Americano over a frappe with cream could change your calorie intake enough to cause weight loss over a few weeks.

Going vegan

Going vegan can be a wonderful way to overhaul your health. However, if you don’t do your research properly beforehand, you can find yourself lacking in energy and losing unwanted weight after making the switch.

Most vegan foods are naturally low in fat. Health-conscious vegans might avoid fats altogether in favour of fruit and vegetables only, but this is a mistake. Vegans l need nourishing foods including plenty of healthy fats, to give you energy and help promote healthy skin. Nuts, tahini, avocados, olive oil, granola and flax seeds are all great for healthy weight gain.

Certain medical conditions

There are some health issues which are known to be causes of weight loss. If you think it could be something serious, go to your doctor to get a specialist opinion. Here are some common illnesses which have weight loss as a major side effect.

Overactive thyroid – also known as hyperthyroidism. This is when the thyroid gland produces too many hormones. With an overactive thyroid, your metabolism ramps up and you burn more calories while at rest, leading to weight loss.⁵
Inflammatory bowel disease (IBD) – including Crohn’s disease and ulcerative colitis have weight loss as a side effect. This could be down to a number of factors – poor appetite, aversion to foods, poor absorption of nutrients from food and nutrients lost through diarrhoea or intestinal bleeding.⁶

Speak to your GP if you think you might be experiencing a form of IBD as it is a potentially serious condition which needs professional diagnosis.

What can I do about unexplained weight loss?

Reflect – you know yourself best. However, even you can miss things. Track your food and drink for a few days (some weekdays and at least one weekend day). Make a note of all your activity, not just formal exercise. Think about how well you are sleeping. Have your stress levels changed? Is anything in your everyday routine different?
Eat more – perhaps the most common reasons for weight loss is a calorie imbalance. You could be eating less than your body needs without realising it. If you have a small appetite or if your daily routine is making it tricky to eat enough, that could be the culprit. Keep a food diary for a few days to see if you’re under eating.
Digestive help – if your digestive system isn’t working properly, you won’t get all the nutrition from the food you eat. If you suspect this is the case, try a probiotic, prebiotic, or digestive enzyme to help your system cope.
Check your meds – certain medications can upset your stomach, causing diarrhoea or indigestion and might be a cause of weight loss. These include non-steroidal anti-inflammatory drugs (NSAIDS), some tranquilisers, iron pills, cough medicines, antibiotics or blood pressure medication. Always check with your GP if prescribed medication is giving you side-effects.⁷

If you think you’ve identified the reason you’re dropping pounds, and don’t want to lose weight, you should supplement your usual calories with some energy-dense, healthy snacks such as hummus and pita or nuts and dried fruit.

If you can’t pinpoint your sudden weight loss to any dietary or lifestyle changes, there could be an underlying medical issue. Chat to your doctor to put your mind at rest.

Last updated: 9 July 2020

Sources
1 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4263906/
2 https://www.nhs.uk/conditions/stress-anxiety-depression/understanding-stress/
3 https://www.nhs.uk/conditions/unintentional-weight-loss/
4 https://www.housebeautiful.com/uk/lifestyle/g162/home-improvements-diy-calories-burnt/
5 https://www.nhs.uk/conditions/overactive-thyroid-hyperthyroidism/
6 https://www.crohnscolitisfoundation.org/diet-and-nutrition/malnutrition-and-ibd
7 https://www.nhs.uk/live-well/eat-well/common-digestive-problems-and-how-to-treat-them/