Diets high in meat and cheese, which are acidogenic and low in fruits and vegetables, which are alkalising, increase the dietary acid load (DAL) of the diet. Diets with a high DAL have been associated with poor health outcomes and the development of heart disease and type 2 diabetes. Plant-based diets have been associated with a lower DAL, however very little research exists on this. Individuals following a vegan diet have been shown in previous studies to have a reduced DAL, however it is unclear whether this was due to a reduced calorie intake or because of the diet composition. This post-hoc study aimed to investigate this and determine whether eating a vegan diet for 4-weeks reduced DAL and how this compares to 4-weeks of a diet rich in meat. The results showed that after 3-weeks, the vegan diet significantly reduced the DAL compared to the meat-rich diet, which increased the DAL. Interestingly all the participants in this study were put on the same balanced diet for 7 days prior to commencing the trial, reducing the chance that results would be affected by a prior diet. It was concluded that a vegan diet as opposed to a meat-rich diet may be of benefit to health outcomes through lowering DAL. This study could be used by healthcare professionals to understand that a balanced vegan diet may be of benefit to those who have heart disease and/or type 2 diabetes. However as this trial did not measure indicators of type 2 diabetes or heart disease, these associations are speculative.