Should You See Your GP Before Trying to Lose Weight?
Do you need to see your GP before trying to lose weight?
For most people, deciding to eat a little differently, cook more meals at home or start walking more doesn’t mean you need to book a doctor’s appointment first.
But there are situations where getting some professional advice before making significant changes to your diet or activity levels is a really sensible idea.
I think this is particularly important because weight-loss advice online tends to assume we’re all starting from exactly the same place.
We’re not.
Someone taking medication for diabetes may need completely different advice from someone without diabetes. Someone with kidney disease shouldn’t necessarily follow the high-protein diet their favourite influencer is promoting. And someone with a history of disordered eating may find calorie tracking considerably more harmful than helpful.
Your health matters more than following a particular diet perfectly.
So let’s look at when you can probably just get started, when it’s worth talking to your GP or another healthcare professional, and some of the health issues that can affect how you approach weight loss.
Does everyone need a health check before losing weight?
No. That’s not routinely necessary for everybody.
If you’re generally well and simply want to make sensible changes such as eating a more balanced diet, watching portion sizes and becoming more active, you don’t usually need a complete set of blood tests before you’re allowed to begin.
However, NHS guidance recommends speaking to a GP or healthcare professional before making lifestyle changes to lose weight if you have a medical condition, a special diet for health reasons, or an eating disorder or history of one.
There are also circumstances where your GP may be able to offer support you hadn’t realised was available. So rather than thinking everyone needs medical permission to lose weight, I’d think of it as:
Is there anything about my health, medication or relationship with food that means generic weight-loss advice might not be appropriate for me?
If the answer is yes, get individual advice.
What health conditions can affect weight loss?
Lots of health conditions can influence your weight, appetite, ability to exercise or the type of diet that’s appropriate for you.
The NHS notes that weight management can be more difficult for people with certain mental health conditions, disabilities and conditions including an underactive thyroid and Cushing’s syndrome. Some medications can also contribute to weight gain.
That doesn’t necessarily mean you can’t lose weight. It means the answer isn’t always as simple as somebody telling you to “eat less and move more”. Here are some circumstances worth considering.
Diabetes
If you have diabetes, I’d definitely involve your healthcare team before making dramatic dietary changes. Food intake, activity and weight loss can all affect blood glucose, and some diabetes medications can cause low blood sugar.
That becomes particularly important if you’re planning a significant reduction in calories or carbohydrates, fasting, or dramatically increasing your exercise. You may also have access to specialist support.
For example, the NHS offers specific weight-management support for some people living with obesity alongside diabetes or high blood pressure. The important thing isn’t that people with diabetes shouldn’t lose weight.
It’s that generic diet advice may not take your medication and blood-glucose management into account.
Thyroid problems
Thyroid conditions are probably one of the first things people think about when their weight isn’t behaving as expected. An underactive thyroid can contribute to weight gain and may make weight management more difficult.
However, I wouldn’t assume that difficulty losing weight automatically means you have a thyroid problem. If you’re experiencing symptoms that concern you, talk to your GP. They can decide whether investigations such as blood tests are appropriate. This is far better than spending money on one of the endless “hormone balancing” products being advertised online.
PCOS and other hormonal conditions
Hormonal conditions can affect weight and appetite too. PCOS, for example, is associated with insulin resistance in many people and can make weight management more challenging. Again, though, I’d avoid the internet rabbit hole where every difficulty losing weight is diagnosed as “hormonal imbalance”.
If you have symptoms that make you wonder whether something medical is going on, that’s a conversation for your GP. Getting the right diagnosis is considerably more useful than trying to fix an imaginary hormone problem with supplements.
Kidney disease
This is one where following random diet trends can be particularly unhelpful. People with chronic kidney disease may have specific dietary requirements depending on the severity of their condition and other factors. That can include individual advice around things such as protein, salt, potassium or phosphate.
So if you have kidney disease, don’t assume a very high-protein weight-loss diet is automatically suitable for you. Speak to your healthcare team or renal dietitian about what is appropriate for you.
Liver disease
Weight management can be relevant to liver health, particularly for people with metabolic dysfunction-associated steatotic liver disease (MASLD), previously commonly called non-alcoholic fatty liver disease or NAFLD.
But having liver disease is another reason I’d want individual advice rather than jumping onto an extreme diet. The goal isn’t to lose as much weight as physically possible in the shortest time. A sustainable approach that considers your overall health is much more useful.
Heart conditions and high blood pressure
If you have heart disease, significant high blood pressure or another cardiovascular condition, your doctor may have specific advice about exercise, diet or medication.
That doesn’t mean physical activity is automatically dangerous. Far from it. But there’s an enormous difference between becoming gradually more active and suddenly attempting a brutal high-intensity workout because someone on YouTube promised it burns 800 calories.
If you have a diagnosed heart condition or have been advised to limit certain activities, follow your healthcare team’s guidance.
Breathing problems and mobility difficulties
Conditions affecting your breathing, joints, mobility or physical ability don’t mean exercise isn’t for you. They may mean the exercise needs to fit you.
If walking for 30 minutes isn’t realistic, perhaps five minutes is.
If standing exercise is difficult, seated exercise might be appropriate.
If running hurts, there are countless other activities.
I think this is one of the biggest mistakes we make with exercise advice: treating the standard workout as compulsory and the adapted version as somehow inferior. It isn’t.
Exercise for overweight and obese beginners
Gentle exercise that really counts
Eating disorders or a difficult relationship with food
If you currently have an eating disorder or have had one previously, speak to an appropriate healthcare professional before starting a weight-loss programme. That’s specifically included in current NHS weight-loss advice.
And I would extend that caution to anyone who recognises worrying behaviours around food and weight in themselves. Calorie counting isn’t psychologically neutral for everyone. Neither is weighing yourself every day.
Nor is labelling food as “good” and “bad”, constantly checking your body or trying to eat as little as possible. I’ve learned from my own experiences that something can produce weight loss and still not necessarily be good for your relationship with food. If trying to lose weight starts making you obsessive, anxious or frightened of eating, that’s worth taking seriously.
The Day I Realised I Was Obsessed With the Scales
I Lost 10 Stone and Still Struggled With Food
Mental health and weight loss
Your mental health matters too.
Depression, anxiety and other mental health difficulties can affect appetite, motivation, sleep and activity. Some medications can also affect weight. The NHS includes some mental health conditions and medications among factors that can make maintaining a healthy weight more difficult.
But I’d be wary of turning weight loss into another stick to beat yourself with. There have been times in my life when getting through the day was more important than whether I’d eaten the nutritionally perfect dinner. Sometimes the most appropriate health goal isn’t losing weight as quickly as possible. It might be getting your mental health into a more stable place first.
What about sleep apnoea?
Sleep apnoea is associated with obesity, and weight loss can be part of its management for some people.
But if you suspect you have sleep apnoea – perhaps because of loud snoring, pauses in breathing during sleep or significant daytime sleepiness – don’t simply decide you’ll lose weight and see whether it disappears.
Speak to your GP.
Sleep apnoea can require treatment in its own right. Read about my experience with sleep apnoea if you want to know how I manage mine.
Do you need blood tests before losing weight?
Not automatically. Your GP might arrange blood tests if your symptoms, medical history or other factors suggest they’re appropriate. For example, investigations might sometimes look at blood glucose, thyroid function, cholesterol, liver function or other markers depending on the individual situation.
What if you can’t lose weight despite trying?
This is slightly different. If you’ve been making reasonable changes for some time and are struggling, it may be worth looking at what’s happening before assuming your body is somehow broken.
First, check the ordinary explanations.
Portion sizes can creep up. Drinks count. Weekends count. Our energy needs change as our weight changes. And sometimes we simply overestimate how active we are.
I’ve written a separate guide about why you might not be losing weight, which goes through those possibilities in much more detail.
But medical factors can sometimes play a role too. Current NHS guidance recognises health conditions, disabilities, medications, genetics, age and menopause/perimenopause among factors that can make weight management more difficult.
If you’re concerned, speak to your GP rather than diagnosing yourself.
What if you’re losing weight without trying?
This is completely different from struggling to lose weight.
Unintentional weight loss should always be checked.
The NHS advises seeing a GP if you continue losing weight without changing your diet or exercise. Unexplained weight loss can have many causes, ranging from stress and mental health problems to digestive, hormonal and other medical conditions.
So if the scales are dropping and you haven’t been trying to make that happen, don’t simply celebrate the unexpected weight loss. Get it checked.
Do you need to lose weight before your doctor will help you?
This is something I wanted to include because people living in larger bodies sometimes worry that every health problem will simply be blamed on their weight. Weight can absolutely affect health.
Living with obesity is associated with increased risks of conditions including type 2 diabetes, cardiovascular disease, high blood pressure, osteoarthritis and fatty liver disease. Even relatively modest weight loss can improve some health measures.
But that doesn’t mean every symptom is caused by your weight. You still deserve appropriate investigation and treatment for health concerns. If something feels wrong, don’t put off asking for help because you’ve convinced yourself you need to lose three stone before you’re allowed to see a doctor.
What about weight-loss injections?
They aren’t simply diets you start yourself. Eligibility, contraindications, side effects and monitoring matter, and they should be obtained through an appropriate regulated healthcare route.
The NHS currently lists semaglutide, tirzepatide and liraglutide among medicines that may be offered to eligible people alongside diet and lifestyle support.
GLP-1 and weight-loss medication guide
And if you’re using one, make sure the healthcare professional prescribing it knows about your medical conditions and other medications.
What about very low-calorie diets?
The NHS says very-low-calorie diets aren’t suitable or safe for everyone and are generally used with specialist support in particular circumstances.
That’s very different from deciding by yourself that eating 700 calories a day will get the weight off faster. Faster isn’t automatically better.
I’ve written separately about how much weight it’s healthy to lose each week, because this is something my own attitude towards weight loss has changed enormously on. Your existing article discusses the commonly recommended gradual rate of around 0.5–1kg (1–2lb) a week.
Your health should determine the plan – not the other way around
I think this is probably the biggest lesson I’d take from all of this. Don’t pick a weight-loss plan and then try to force your body, health conditions and life to fit around it.
Start with you.
- What medications do you take?
- Are there foods you need to eat or avoid for medical reasons?
- What movement can you comfortably do?
- How is your relationship with food?
- What has happened when you’ve tried losing weight previously?
- What can you realistically sustain?
The best approach isn’t necessarily the one that promises the biggest loss this month. It’s the one that helps you look after your health while making changes you can actually live with. And sometimes the first step isn’t downloading a calorie-counting app. Sometimes it’s having a conversation with your GP.
Sources and further reading
If you want to read more about this from medical professionals here are some NHS guides for you.
- NHS – Overweight and obesity in adults — health risks, treatment options, weight-management services and factors that can affect weight.
- NHS – Healthy eating when trying to lose weight — including when to speak to a healthcare professional before changing your lifestyle.
- NHS – Unintentional weight loss — when unexplained weight loss should be assessed.
- NHS – Support for weight-related health conditions — NHS and charity support for people living with weight-related health conditions.
Medical disclaimer
This article provides general information and isn’t a substitute for individual medical advice. Your health conditions, medications and nutritional requirements can affect which approaches to weight management are appropriate for you. Speak to your GP, pharmacist, dietitian or another appropriate healthcare professional if you’re unsure.
