The share of ultra-processed foods determines the overall nutritional quality of diet in British vegetarians.

The aim of this study was to describe the dietary intake of British vegetarians according to the Nova classification and to evaluate the association between the consumption of ultra-processed foods and the nutritional quality of the diet. We used data from the UK national survey (2008/2019). Food collected through a 4-d record were classified according to the Nova system. In all tertiles of the energy contribution of ultra-processed foods, differences in the average nutrient intake, as well as in the prevalence of inadequate intake, were analysed, considering the values recommended by international authorities. Ultra-processed foods had the highest dietary contribution (56·3 % of energy intake), followed by fresh or minimally processed foods (29·2 %), processed foods (9·4 %) and culinary ingredients (5 %). A positive linear trend was found between the contribution tertiles of ultra-processed foods and the content of free sugars ( β 0·25, P < 0·001), while an inverse relationship was observed for dietary fibre ( β -0·26, P = 0·002), potassium ( β -0·38, P < 0·001), Mg ( β -0·31, P < 0·001), Cu ( β -0·22, P < 0·003), vitamin A ( β -0·37, P < 0·001) and vitamin C ( β -0·22, P < 0·001). As the contribution of ultra-processed foods to total energy intake increased (from the first to the last tertile of consumption), the prevalence of inadequate intake of free sugars increased (from 32·9 % to 60·7 %, respectively), as well as the prevalence of inadequate fibre intake (from 26·1 % to 47·5 %). The influence of ultra-processed foods on the vegetarian diet in the UK is of considerable magnitude, and the consumption of this food was associated with poorer diet quality.