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When Does Weight Loss Become a Concern?

Weight loss can become concerning when it isn't healthy. We talk about what this might look like and when you should be concerned about that.
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Weight loss is something that many people pursue, but it’s also something that can happen as a result of physical or mental illness.

Not all weight loss is bad, but not all of it is good, either.

Weight loss becomes concerning when it stops being healthy, for example, rapid weight loss can be concerning.

Unexplained weight loss is especially concerning due to the fact it isn’t deliberate. 

However, some cases of deliberate weight loss can also be concerning if they start to affect your mental health or the rest of your body.  

In this article, we talk about some of the concerns when it comes to weight loss and guidelines for healthy, sustainable weight loss so that you can make informed choices. 

When Should You Worry About Weight Loss? 

A majority of people that are trying to lose weight don’t experience any problems.

However, there are certain situations where weight loss can be concerning.

One example is if you’re losing weight without trying or changing anything about your lifestyle.

Another example of concerning weight loss would be when you lose more than the recommended amount, or if you’re underweight.  

Person stepping on scales

Weight loss can also affect your mental health and eating habits.

Because of this, it’s important to be aware of different types of eating disorders and their symptoms. 

There are sometimes stereotypes that are attached to various eating disorders. 

However, you don’t have to look a certain way or have a certain body type to develop any kind of eating disorder.

You should speak to your GP if you think that you might be developing an unhealthy relationship with food.  

You should worry about your weight loss if you find that you’re obsessing over food, restricting your calorie intake more than you should, or that your mental health is affected by weight loss. 

Eating disorders can severely affect your mental health and long-term relationship with food.

Luckily, help is available from BEAT.  

Most cases of weight loss are unproblematic and are often intentional and safe.

However, you should start to worry about weight loss if: 

  • It isn’t intentional 
  • You’re underweight or at risk of becoming it 
  • It begins to affect your mental health 
  • You also experience other symptoms that may be unexplained 

If your weight loss is unexplained, you should also look out for symptoms such as:  

  • Fatigue 
  • Change in toilet habits 
  • Change in appetite (not caused by medication) 
  • Increased illnesses 
  • Increased infections 

The NHS have more information and advice about unexplained or unintentional weight loss here

What is the reason for sudden weight loss?  

There could be many reasons behind sudden weight loss. 

Many people find that their weight loss can be quite sudden at first.

This is fairly common for a couple of weeks when you first start trying to lose weight. 

Unfortunately, sudden weight loss is also a non-specific symptom of several health conditions.

This means that you might have to go for tests if you’ve suddenly started losing weight without trying to. 

weight loss check

Sometimes, sudden weight loss might indicate an underlying health condition.

This is especially true if you haven’t changed anything about your lifestyle but have still noticed a reduction in weight.

This could indicate an underlying health problem.

Conditions that could cause weight loss include:  

  • Hyperthyroidism 
  • Addison’s disease 
  • Celiac disease 
  • Dental issues that may affect chewing and swallowing 
  • Some sort of infection 
  • Gastrointestinal issues 
  • Cancer 

It’s also important to remember that weight loss can be a side effect of some medications such as Semaglutide (Ozempic), some diabetes treatments, and other medicines.

It’s always worth checking the patient information leaflet for the medicines that you’re taking to see if weight loss is listed as a side effect. 

Some weight-loss medications may also increase the amount of weight that you lose. 

Sudden weight loss can also happen after a stressful life event.

Stress can change our behaviours and eating habits, because of this, it’s fairly common for weight to change after a stressful or traumatic event. 

If you’ve recently gone through a hard time and found yourself stressed, it could possibly explain any weight loss you’ve been experiencing.  

concerned about weight loss

In a vast majority of cases, sudden weight loss isn’t caused by cancer or anything untreatable.

However, if you’re concerned that you’re losing too much weight too quickly you should still make an appointment to see your doctor.

They may want to send you for tests to make sure that your body is functioning as it should be. 

How much is safe weight loss?  

“Safe” or healthy weight loss is generally around 1 to 2lbs a week.

This is the guideline that’s recommended by the NHS.

However, if you lose more than 1-2lbs a week at first, don’t panic!

Weight loss is often more rapid in the first few weeks.

This is because your body is using its glycogen stores for energy.

As glycogen is partly made of water, all of the weight from the fluid is released.

This is a fairly common process with weight loss, and your weight should stabilise after a few weeks once your body starts to burn fat.  

Those with a larger BMI will generally lose weight at a faster rate as well.

That’s partly due to the fact that you burn more calories if you’re carrying excess weight.

This is thanks to your body’s BMR or basal metabolic rate.

Your BMR is how many calories your body needs to function whilst at rest. In other words, it’s the number of calories that your body burns when you’re completely resting. 

Those that are heavier often have a higher BMR, meaning that they burn more calories than someone of a “normal” BMI. 

As their weight reduces, so does their BMR and rate of weight loss. 

If you want to find your own BMR, there are various calculators such as this one where you can input your age, gender, height and weight for a personalised result. 

how much is safe weight loss

If you do occasionally lose more than 2lbs a week, it’s nothing to worry about. Weight does naturally fluctuate.

Our routines also change from time to time which can also affect weight loss.

However, if you find that you’re consistently losing more than 2lbs a week, you may need to slow down.  

Diet culture has unfortunately made us think that a fairly substantial weight loss in a short amount of time is to be expected. 

This certainly isn’t the case for most people. 

There’s no healthy fast-track to weight loss. Aiming to lose 1-2lbs a week is the healthiest and most sustainable option. 

Most people are able to achieve this by reducing their calorie intake and increasing their activity levels.

However, some people may need medical treatment to help them to lose a healthy amount of weight.  

Rapid weight loss is only generally recommended in cases where a patient is in need of urgent surgery but would be at risk of complications due to their BMI.

In these cases, patients are often placed on a short-term restrictive diet in order to lose a larger amount of weight in a short time for medical purposes.

If rapid weight loss hasn’t been recommended to you, you should assume that it’s safest to aim for a maximum weight loss of 2lbs a week. 

How much weight loss is concerning in a month? 

Losing much more than 10lbs a month after your first few weeks is concerning.

As we’ve already mentioned, you’re likely to lose some water weight during the first few weeks of weight loss.

However, if you’re losing much more than 10lbs a month after this, you may need to slow down.  

Aiming to lose more than 10lbs a month could mean that you end up severely restricting your food intake.

This can be incredibly harmful to your body and even hinder any weight loss you’re hoping for.  

measure weight loss

You should only aim to lose more than 10lbs a month if your own GP recommends it for medical reasons.

It can be easy to get carried away with weight loss. Especially if you have a lot of weight to lose.

However, myBMI know that the most successful way of losing weight for good is to take it slow and steady.

This way, you’ll be more likely to sustain weight loss years into the future.  

If you’re losing 10lbs or more per month, you should try completing a food diary to see how many calories you consume in an average day.

You should also calculate your basal metabolic rate (BMR) by using the calculator we linked to earlier.

If you’re not getting enough nutrients, you could experience muscle wastage.  

What is considered rapid weight loss? 

Consistently losing more than 2lbs a week is considered rapid weight loss.

Rapid weight loss is rarely recommended unless your weight is causing health problems or preventing you from accessing care.

Rapid weight loss isn’t concerning in these cases as it’s guided by medical professionals and only done for a short amount of time.

However, if you find that you’re regularly losing more than 2lbs a week, you should think about slowing down your rapid weight loss. 

If you’re losing 2lbs or more a week and aren’t trying to, you should make an appointment with your GP.  

Although many people want to lose large amounts of weight in a short time, it really isn’t recommended.

Rapid weight loss can lead to a host of problems and complications such as:  

  • Gallstones 
  • Menstrual irregularities 
  • Loss of muscle 
  • Malnutrition 
  • Vitamin deficiencies 
  • Hair loss 
  • Fatigue 

Rapid weight loss can also cause other health issues that aren’t listed above.  

You may have noticed muscle loss amongst the list of alarming issues that fast weight loss can cause.

This is because you don’t just lose fat when you lose weight, you also lose some of your muscle.

This can then go on to cause weakness and pain when you may not have experienced it before.

This is just one of the many reasons that rapid weight loss isn’t advised no matter what your starting weight is.  

Rapid weight loss is often caused by severely restricting calorie intake, some liquid diets aim to do this deliberately.

These kinds of diets aren’t sustainable in the long term.

Ultimately, when the liquid diet is stopped and calorie intake increases, weight regain will happen.

This is why it’s recommended to only decrease your calorie intake by 500kcal less than what your body burns.  

What’s considered as rapid weight loss might seem average or even slow to some people.

However, the guidelines are in place to ensure a healthy and sustainable weight loss with minimal risk of problems.

Making sure that you stick to a guide of 1-2lbs per week ensures that you should still get enough nutrients.

This means that you’re less likely to experience illness, insomnia, and even mood swings.

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Laura Henderson

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