Stress can outweigh being healthy, if being healthy comes with too much stress.
Take it from someone who's white blood cell count was once so high that he was tested for bone-marrow disease, leukaemia, and more... which only resided once stress and pressure was removed mentally.
I learned the power of the mind over your body the hard way, which is why I have the privilege of helping you to avoid doing the same.
So let's make this a little more practical...
You have to weigh up the benefits of what you're doing with the stress that it causes you.
For example: If you are tracking your nutrition (something I'm not a fan of, which is why I do all the calculations for people on The Gut Reset) and you sit in a restaurant with your phone out trying to search and calculate what is contained in what you just ate...
That isn't healthy.
Unless you have a performance based goal that requires this kind of attention to detail, what would be healthier in this situation is using the knowledge that you've developed to make an informed decision, then following your intuition as you eat to ensure you're satisfied, then cracking on with your day.
Another great example is fasting; if you are planing to fast until 2 pm, but you spend from 10 am - 2 pm with your mind closer to the fridge than on what you have to do with your day (after some time adapting to the process of fasting, because that is certainly needed)...
That isn't healthy, no matter what the research says about fasting (trust me, I wrote a book about fasting with over 45 scientific journals referenced).
What would be healthier is finding a protocol that seamlessly slots into your life. Fasting has changed my life for the better, but only because I do it in a way that doesn't live rent free in the back of my mind.
Again, weigh up the benefits of what you're doing with the stress that it causes you.