At the end of the day, the Brahmin needs to ask himself, "Have I evolved?"
This concept of evolution is at the very crux of Brahminism. Different types of evolution come into play as a work-in-progress Brahmin slowly moves towards a state of Brahminism.
At the base is physical evolution. Physical fitness is an absolute pre-requisite. This can be achieved by various practices like Yoga, breathing exercises, workouts and a balanced diet, (preferably sattwic). One doesn't need to force oneself to eat Sattwic food - if the potential of Brahminism is within, his Nature will dictate his food habits and make it Sattwic eventually.
At the next level is mental evolution - a movement from the gross to subtle. This entails progressively attaining higher of mental refinement. A deep appreciation for the finer things in life is what is seen at this level - appreciation of good music, good food, knowledge, arts, science - he will guzzle up all sources of Knowledge and still thirst for more. He will be passionate about knowledge and Truth but at the same time be compassionate about his fellow beings. Charity and giving would start becoming an important characteristic of this phase, as the Brahmin begins to understand, appreciate and realize Maya, Karma, bondage, Yajna, life, cosmos and the true cyclical nature of our universe (birth and death, creation and destruction, giving and taking, existence and non-existence).
The next level is spiritual evolution. With various yoga practices in full swing, with knowledge from books or from a Guru, with a keen metal setup, peak physical form, the spiritual call is bound to happen and when it happens it (the call) will be sudden. From then on, it will be a slow, gradual progression towards towards Truth.
A common mistake that many people make is the assumption that by not doing anything 'evil' they generate good Karma. But that is a mistaken notion. It is indeed true that by doing something 'evil' or something that is not a part of one's duty, one incurs bad karma. However, abstinence of 'evil' actions does not automatically imply the generation of good karma. Good needs to be done to accumulate good karma. Good might mean anything as long as it involves 'giving' something - like charity, helping the poor, taking care of stray animals and feeding them etc. Unless you give, you will not get.
So as we can see the transformation from a Work-In-Progress Brahmin to a True Brahmin is fraught with many difficulties and at all the three levels - physical, mental as well as spiritual. It is by no means an easy task and I would recommend that the Modern Age Brahmin have a checklist of To-dos for each of these levels, and ask himself regularly as to what he has achieved at the three levels.
Ultimately, Brahminism is a matter to be tackled between the person and his Self.