My wife sometimes tells me I have issues with my routines. It's true I don't like variance when it comes to routines, but there are good reasons behind "healthy" routines.
We know that you have a limited supply of will power. Say no to the cookie now, it's most likely leaked out a little of your will power for later. Hopefully, the later isn't as important.
We also know that decisions sack our energy. The more decisions we make the more mental fatigue we accumulate. This leads to either very ill advised decisions, or the opposite, we do nothing. Both of these choices can lead to not so desired results.
It doesn't even half to be important decisions. In fact, it's the small decisions that start to sap our energy, not the big ones. So how do we combat this?
Work through the stuff that really isn't that important and create an automatic pilot for your day.
Figure out what you eat for breakfast. Have the same thing on Monday, every Monday. This goes for the rest of the week as well. This goes for lunch and dinner. Create yourself a menu. One of the reasons I think Intermittent Fasting has become huge, besides it works, it creates a decision free morning. You don't eat. Talk about freeing up some mental energy.
I wear gray shorts and polo to work every day. I never think about what I'm wearing. The beauty of the uniform.
I lift weight every Monday and Thursday evening. I very rarely miss them except for family obligations. Just part of the week.
I get coffee at my favorite coffee shops on my lunch breaks Tues/Thurs. Again, I not only enjoy this, but I no longer think whats happening for lunch today.
I have a few other things I put into automatic pilot as well, but you get the picture. What is interesting, I often get creative thoughts or come to important decisions while I'm doing the aforementioned things. The freed up mental energy can go to more important stuff.
So if you find yourself feeling just plain old mentally tired, set up some routines.
Make them healthy (donuts for breakfast...em no)
Make theme easy. Creating a fresh 12 ingredient omelet for breakfast, while healthy, sounds like so much work to me, I would never keep it in my routine.
Make them for Everything that doesn't change. We all eat, sleep, bathroom, exercise, grocery shop, ect.
Be Awesome. Use your extra mental energy to do the stuff well and better, that can't be in a routine.