I am on a low-carb ketogenic diet that cuts out anything with sugar and high carbs. I personally don’t have ADHD (my boyfriend has) I have anxiety and depression and irritability and this diet has stopped me feeling irritable. I have to make sweet things instead with erythritol and stevia sweeteners that are expensive but worth keeping my mood calmer. (my reference is from Dr Eric Berg). He recommends Nutritional Yeast flakes (B vits) for people with ADHD and Vit D but he has endless youtube videos you can watch if interested.