A new study conducted by researchers at King’s College London has revealed that adults in the United Kingdom consume a median of only eight different plant-based foods per day, with some individuals eating as few as two. This figure includes not just fruits and vegetables but also herbs, spices, legumes, and oils derived from plants. While this number may seem modest, the researchers argue that increasing the variety—not merely the quantity—of plant-based foods in one’s diet could have significant implications for improving cardiometabolic health across the population.
The study, published in Clinical Nutrition, is the first of its kind in the UK to analyse the types and variety of plant foods consumed and how this diversity correlates with markers of cardiometabolic health, which include cholesterol levels, blood sugar control, and overall nutrient intake. Drawing on data from the UK National Diet and Nutrition Survey for 2016–2017, the researchers assessed the dietary habits of over 670 adults, the vast majority of whom followed omnivorous diets. Participants were grouped according to the daily diversity of plant-based foods they consumed, ranging from an average of 5.5 foods in the low-diversity group to 11 in the high-diversity category.
The findings suggest a strong relationship between dietary diversity and positive health indicators. For instance, individuals with more varied plant consumption exhibited higher levels of HDL cholesterol, the so-called “good” cholesterol known to reduce the risk of heart disease. Additionally, a higher variety of plant foods was associated with lower concentrations of HbA1c, a marker of long-term blood sugar regulation and an important indicator in the prevention and management of type 2 diabetes. These associations held even when adjusting for other factors such as age, body weight, and overall caloric intake.
Beyond biological markers, the study also found lifestyle differences among the groups. Those in the high-diversity group tended to lead healthier lives overall. Only 6% of these participants were smokers, compared with 30% in the low-diversity group. They also had more favourable blood lipid profiles. They were more likely to meet dietary fibre recommendations, although interestingly, they also consumed more total sugar, primarily from fruits and fruit juices. Despite concerns about sugar intake, the researchers noted that the fibre and antioxidants found in fruits might mitigate some of the adverse effects of natural sugars on blood glucose and metabolic health.
According to Dr Eirini Dimidi, Senior Lecturer in Nutritional Sciences at King’s College London and the study’s lead author, the results highlight a gap in current public health messaging. “UK dietary guidelines tend to emphasise the quantity of fruit and vegetables, such as the well-known ‘5-a-day’ message. Our research shows that the variety of plant-based foods consumed may be just as crucial as the quantity for achieving better health outcomes,” she said. Dr Dimidi added that even among the most diverse eaters in the study, key nutrient shortfalls remained, particularly in fibre and several micronutrients essential for immune function and maintaining healthy bones and tissues.
An analysis of food categories revealed that vegetables were the most significant contributors to plant diversity, accounting for just over 21% of the total. This was followed closely by plant-based fats and oils (18.8%) and fruit (17%). Foods with high nutritional value, such as nuts, seeds, and legumes, however, made a surprisingly minimal contribution to overall dietary variety. This highlights a missed opportunity, as these foods are rich in protein, healthy fats, and essential micronutrients that support a range of bodily functions.
In light of these findings, the researchers advocate for a broader and more inclusive understanding of plant-based eating. Dr Dimidi encourages people to incorporate lesser-used ingredients into everyday meals to enhance dietary diversity. Suggestions include adding a spoonful of mixed seeds or crushed nuts to morning porridge, experimenting with different herbs and spices to flavour meals, and varying the types of vegetables used in daily cooking. She points to seasonal produce like courgettes, broad beans, and broccoli in the summer months as easy and nutritious additions. Overall, the study suggests that promoting not only the consumption of plant foods but also their diversity could be a robust public health strategy to improve the nation’s diet quality and reduce the burden of cardiometabolic diseases.
More information: Eirini Dimidi et al, Characterising the diversity of plant-based food and beverage consumption in adults, and exploring associations with cardiometabolic health outcomes: A cross-sectional study, Clinical Nutrition. DOI: 10.1016/j.clnu.2025.07.011
Journal information: Clinical Nutrition Provided by King’s College London
