Short answer
Stop Mental Diet when when the chosen thought is already handled flexibly or monitoring becomes intrusive. The exercise is noticing recurring interpretations and replacing exaggerated ones with more accurate, workable language; once that job is complete, continuing should have to provide new information rather than merely more repetition.
Define enough before you begin
When you can notice the target thought and answer it with a proportionate alternative, stop monitoring and return to the task. This gives the session a practical endpoint. You do not need to wait for perfect certainty, a dramatic mood change or an external result before you are allowed to finish.
A method-specific stop signal
The clearest warning sign is policing every negative thought and turning the method into emotional censorship. If you notice that pattern, shorten the session or stop it entirely. A boundary is not failure; it is what keeps a voluntary method from turning into reassurance or avoidance.
Use Mental Diet Tracker to write the endpoint before you begin. Record what “finished” means for this session, then mark it complete when that point arrives. This is more reliable than negotiating with yourself while emotionally invested in continuing.
When continuing costs more than it adds
After stopping, look for whether self-talk becomes more precise and less behaviourally limiting. That feedback comes from behaviour and the situation itself. Another round of the method may be less informative than waiting, practising, asking a question, getting feedback or simply seeing what happens next.
Before continuing Mental Diet, ask what another session could teach you that the current one has not. Once when the chosen thought is already handled flexibly or monitoring becomes intrusive, the next useful information is more likely to come from behaviour, feedback or waiting. If the only reason to continue is discomfort about ending, treat that as a cue to finish rather than as evidence that more practice is required.
What should replace another round
You can return if the goal, obstacle or context genuinely changes. A later use should have a different purpose, not merely repeat the same exercise because stopping felt uncomfortable. Put a review date in Mental Diet Tracker if that helps you leave the method alone in the meantime.
Stopping does not erase what you already wrote, rehearsed or noticed. It also does not cancel an outcome. Mental Diet can affect attention or preparation, but it does not control chance, institutions, health outcomes or another person’s decisions.
Three different reasons to finish a session
There are at least three valid endpoints for Mental Diet. First, a task endpoint: when the chosen thought is already handled flexibly or monitoring becomes intrusive. Second, a quality endpoint: the exercise is repeating itself rather than producing clearer thinking. Third, a cost endpoint: time, sleep, comfort or concentration is starting to suffer. You do not need all three signals; any one can be enough to stop.
When you can notice the target thought and answer it with a proportionate alternative, stop monitoring and return to the task. Treat that as the hand-off point. Once the method has produced something you can test, more internal work is usually less informative than the test itself.
What continuing can cost
The main risk with Mental Diet is policing every negative thought and turning the method into emotional censorship. Continuing past the useful point can make the method occupy more attention than the goal deserves. It can also blur the difference between preparation and reassurance, because the session continues not to learn something new but to reduce discomfort about stopping.
If policing every negative thought and turning the method into emotional censorship starts to appear, give Mental Diet a real break instead of replacing it with mental rehearsal of the same routine. Use Mental Diet Tracker to note the pause, then leave the exercise alone until the context changes or a planned review date arrives. The break is part of the boundary, not lost practice.
Record why you stopped
In Mental Diet Tracker, add one short line: “Stopped because…” This creates a useful record for later review. If you return, you can see whether the original reason changed. A return based on new evidence is different from reopening the exercise because the old uncertainty resurfaced.
A thought does not need endless correction
Once you have a proportionate alternative to the target thought, return to the activity. If the old thought appears again, noticing it is enough; you do not need another full Mental Diet session every time.
Bottom line
Stop Mental Diet when when the chosen thought is already handled flexibly or monitoring becomes intrusive. Use the method to produce clarity or preparation, then let behaviour, feedback and ordinary life take over.