Given the growing popularity of plant-based diets, this study investigated the dietary habits and self-reported health outcomes of health-conscious adults consuming plant-based diets. A cross-sectional online survey (n = 315) was distributed to members of Plant-Based Health Professionals UK, a community interest company. Dietary intake was assessed through a food frequency questionnaire. Data were summarised descriptively. Dietary habits among respondents following a whole food plant-based (WFPB) and vegan diet were compared using hypothesis tests. Respondents reported following a WFPB (61%), vegan (28%) and semi plant-based (11%) diet. Median time on current dietary pattern was 5 years. Daily or more frequent consumption was reported for the following foods: fruits 77%, berries 51%, green vegetables 48%, cruciferous vegetables 45%, other vegetables 64%, beans/legumes 41%, whole grains 62%, nuts and all seeds 63%. Consumption of ultra-processed foods and plant-based meat alternatives was low. About 93% of those on a WFPB or vegan diet supplemented with vitamin B12 and 61% with vitamin D. The median body mass index was 22.4 kg/m2. Fifty per cent of participants reported weight loss after adopting a plant-based diet, with a median loss of 6.4 kg. Thirty-five per cent reported reversing or improving an underlying health condition, and 15% were able to stop or reduce prescribed medication use as a result of dietary changes. This study suggests that a well-planned plant-based diet is achievable and sustainable in a community setting and can be associated with health benefits. How to best encourage such sustainable diets among the broad population requires further research.