The Nutrition Gap Report: Are UK dieters getting the nutritional support they need?
PortionIQ was created with a mission to help people make more informed choices about their nutrition and weight management. Through our range of products designed to support people using GLP-1 medications and anyone managing their weight, we help people better understand their nutritional needs and make informed choices throughout their journey.
For anyone who is looking to manage or lose weight, getting the right nutrition remains an important part of the journey. Eating less can make it more challenging to get enough of the nutrients the body needs, while people may also face different nutritional challenges depending on how they are approaching weight loss.
And, with an estimated 1.6 million adults having used GLP-1 medications between early 2024 and early 2025, with those numbers set to potentially rise over the coming years thanks to the introduction of GLP-1 pills, weight loss continues to be a big topic of debate. However, what is often missing from the discussion is the nutritional education and support gap that many dieters experience regardless of their weight loss route.
To explore this further, we surveyed 1,000 UK adults currently dieting to lose weight, split evenly between those taking GLP-1 medications and those who are using other weight loss methods. We looked at their motivations for losing weight, where they seek nutritional advice, how confident they feel in their nutritional knowledge and the challenges they face throughout their weight loss journey.
Key takeaways
Do GLP-1 users think they need more nutritional support?
In our survey, 92% of GLP-1 users agreed that people managing their weight should receive more nutritional education and support during their weight loss journey. 
This highlights a potential gap between the focus on weight loss itself and the wider nutritional needs of people taking GLP-1 medications.
For many people, weight loss is not solely about improving their health. Our research found that 45% of GLP-1 users are losing weight for appearance and confidence, while 19% said overall health improvement was their reason.
Meanwhile, just 9% said they were taking the medication because it had been recommended by a medical professional.
Where are GLP-1 users getting their nutritional advice?
When it comes to nutritional support and guidance, people have a wide range of sources to turn to.
For GLP-1 users, GPs remain an important source of guidance, with 46% saying they turn to them for nutritional advice, even though 90% of UK patients are now accessing GLP-1s for weight loss privately or off-label. According to our survey, just 9% of GLP-1 users were on them due to being recommended by a healthcare professional.
However, online sources are also playing a significant role. Across all respondents, including those managing their weight both with and without GLP-1 medications, 25% said they had received nutritional information from online articles, while 21% had turned to social media and 10% to influencers and content creators.
This figure was lower among respondents aged 55 and over, with 18% turning to online articles for nutritional information, 5% using social media and just 1% relying on influencers and content creators.
While some influencers and content creators could be regulated diet or healthcare professionals, many industry bodies including the BMJ have raised concerns that biased or misleading medical advice shared by social media influencers and content creators could cause harm to the public.
According to our study, male GLP-1 users are more likely to turn to influencers and content creators for advice (16%) compared to female GLP-1 users (9%). Male GLP-1 users were also more likely to turn to the NHS (52%) than female GLP-1 users (37%).
Male GLP-1 users also were more likely to be on the medication following a healthcare professional’s recommendation, with 13% of male GLP-1 user respondents stating this as their main reason for taking them, compared to just 4% of female respondents.
How confident are dieters about their nutrition?
Despite the clear appetite for greater nutritional education, most GLP-1 users say they feel confident about their nutritional knowledge, however there were some differences based on age.
Overall, 90% of GLP-1 users said they were confident in their knowledge of why essential nutrients are needed in the body and the potential effects of not getting enough.
However, across all respondents, including both dieters using GLP-1s and those using other weight loss methods, nearly 20% of those aged 55 and over were not confident in their knowledge of essential nutrients, compared with just 11% of those aged 18-24.
How has widespread GLP-1 use affected nutritional confidence?
Our research shows that confidence in nutritional knowledge also varies depending on how long someone has been taking GLP-1 medication.
The NHS began rolling out tirzepatide (Mounjaro), a dual GIP/GLP-1 receptor agonist, for the management of weight in June 2025, with up to 220,000 people in England expected to receive the medication through the NHS over its first three years of availability.
The rapid adoption of these medications, whether accessed through healthcare professionals or elsewhere, may have shaped people’s understanding of how to manage their health while taking them.
Among those who had been taking GLP-1 medication for two years or more, 29% were not confident in their knowledge of essential nutrients, compared with 12% of those who had been taking it for less than one month.
A similar pattern emerged when respondents were asked whether they felt confident that they were getting enough nutrients, and whether they could spot the signs of a vitamin deficiency.
Overall, 81% of GLP-1 users said they were confident they were getting enough nutrients, but this fell to 57% among those who had been taking GLP-1 medication for two years or more.
By comparison, 81% of those who had been taking it for less than one month said they were confident they were getting enough nutrients.
This suggests that while confidence may be relatively high among newer GLP-1 users, there is a clear knowledge gap among longer-term users who started the medication before widespread adoption.
It also raises questions about the nutritional support available to people who started GLP-1 treatment before these medications became more widely established, when reliable guidance was less readily available.
What nutritional challenges are GLP-1 users experiencing?
Although a majority of survey respondents feel confident about knowing their nutritional needs while dieting, many people reported experiencing one or more unwanted reaction that could be associated with not getting enough essential vitamins and nutrients.
These included eating much smaller portions, reduced appetite, fatigue or low energy, skipping meals, headaches, constipation, dehydration, nausea, diarrhoea, difficulty eating enough protein, muscle cramps and hair thinning.
Beyond eating smaller portions (45%) and experiencing a reduced appetite (44%), fatigue or low energy was the most commonly reported unwanted reaction among GLP-1 users, affecting 29%.
Other commonly reported unwanted reactions included:
-
Skipping meals (28%)
-
Headaches (24%)
-
Constipation (22%)
-
Nausea (21%)
-
Dehydration (17%)
-
Diarrhoea (16%)
-
Muscle cramps (14%)
-
Hair thinning (9%)
By comparison, just 11% of dieters using other weight loss methods reported experiencing constipation, while only 5% reported nausea.
Only 8% of GLP-1 users said they had not experienced any of the unwanted reactions listed in our survey. This compares with 28% of people who were dieting using methods other than GLP-1 medications.
Protein is particularly important during weight loss, with some expert guidance recommending at least 1.2g of protein per kilogram of body weight per day for people using GLP-1 medications.
Meeting this target was a challenge for GLP-1 users, with 14% saying they found it difficult to get enough protein. This compared with 9% of those who are using other weight loss methods.
Younger people are confident, but still facing nutritional challenges
Our research also revealed an interesting gap among younger respondents.
Among those aged 18 to 24, including both GLP-1 users and those losing weight through other methods, 84% said they were confident they were consuming enough essential nutrients, making them the most confident age group.
However, this age group was also the most likely to say they found it difficult to get enough protein (16%). They were also most likely to report muscle cramps (16%), hair thinning (21%), and headaches (26%).
Headaches remained relatively common among older age groups too, affecting 26% of those aged 25 to 34 and 26% of those aged 35 to 44. This fell to 18% among those aged 45 to 54 and 10% among those aged 55 and over.
The findings suggest that confidence in nutritional knowledge does not necessarily mean people are free from unwanted reactions associated with managing their nutrition while dieting.
The nutrition gap
Our survey points towards a potential nutrition gap among people using GLP-1 medications.
People overwhelmingly believe they should receive more nutritional education and support (92%), yet they are accessing guidance from a wide range of sources, including online resources such as social media and content creators.
At the same time, many GLP-1 users report physical symptoms and challenges around their diet, including difficulty getting enough protein.
Confidence also appears to decline among those who have been taking GLP-1 medication for longer, despite newer users reporting relatively high levels of confidence.
Together, these findings suggest that nutritional support needs to be considered as an ongoing part of weight management, rather than simply something people seek when they first begin their journey.
What does good nutritional support look like?
Mark Gilbert (BASc, RNutr, CISSN), our nutritionist at PortionIQ, said:
“GLP-1 medications can play an important role in supporting weight management, but whether someone is taking a GLP-1 or dieting without one, good nutrition remains an important part of the journey. For those taking GLP-1s, a reduced appetite can make it more challenging to get all the nutrients the body needs from smaller portions of food.
“Our research shows that people across both groups recognise the importance of nutritional support, while the challenges and sources of advice they rely on can vary. Making sure everyone managing their weight has access to clear, reliable nutritional information can help them feel more confident about what they are eating and make informed choices throughout their journey.”
According to the latest National Diet and Nutrition Survey, just 4% of UK adults meet the recommended daily fibre intake, while only 17% meet the ‘Five A Day’ recommendation. This suggests that understanding and maintaining a balanced diet can be challenging regardless of how someone is approaching weight loss.
If you’re taking a GLP-1 medication or dieting without one, there are several key nutritional considerations to keep in mind when managing your weight.
1. Make protein a priority
Protein is an essential nutrient that plays an important role in maintaining and repairing the body. With 14% of GLP-1 users in our survey saying they find it difficult to get enough protein, including a source of protein as part of meals and snacks can help people make the most of smaller portions.
2. Focus on nutrient-dense foods
When appetite is reduced, choosing foods that provide a good range of essential nutrients can help make each meal count. A balanced diet should include a variety of fruit and vegetables, wholegrains, protein sources and healthy fats to provide the vitamins, minerals, and fibre that the body needs.
3. Don't forget about hydration
Staying hydrated is an important part of good nutrition and overall wellbeing. Alongside fluids, electrolytes such as sodium, potassium and magnesium help maintain fluid balance and normal muscle and nerve function. Drinking regularly throughout the day can help support hydration, particularly when appetite and eating habits change.
4. Choose trusted sources of advice
Our research found that 46% of GLP-1 users turn to GPs for nutritional advice, while 27% use online articles. With nutritional advice readily available online, it is important to consider the reliability of the information you are following and seek guidance from qualified healthcare or nutrition professionals where appropriate.
Methodology
The research was conducted by Censuswide among a sample of 1,000 UK people who are on a diet in order to lose weight, split evenly between those taking GLP-1 medications and those who are losing weight using other methods. The data was collected between 14 and 19 August 2026.
Censuswide is a member of the Market Research Society (MRS) and the British Polling Council (BPC), and a signatory of the Global Data Quality Pledge. It adheres to the MRS Code of Conduct and ESOMAR principles.