Analysis paralysis

Don’t over analyze things, just do it.

Don’t do lots of calorie counting or other diet plan calculations unless you like calculating. All you really need to know is less calories absorbed and more calories expended = Weight loss. Just do it in a healthy way to avoid health problems later on. So again just do it, and think happy thoughts while exercising, or don’t even care if you feel pain. Ignore that feeling.
Another way to just do things is to set up fool proof systems. Such as just not buying bad food at the store forces out the thought process of deciding on whether to eat the leftover cake in the fridge or the healthy food right beside it. It's always hard to fight human urges. See also: Automatic Success Theory
When it comes to life, lots of avenues to success are to just try, try again. Which means that you actually have to fail as a means of learning to succeed. Also called the school of hard knocks. You don’t become a professional athlete by thinking it through and then automatically being the best in the world. The real world is the best teacher, because when you test it, it gives you absolute proof of how the world around you really works. This can also be seen as using the scientific method, of theorizing and properly actually testing those theories.
You can never convince yourself of all of the positive or negative consequences or out comes to a Project because of the Butterfly effect and the comedic rule of “Murphy’s law”. The universe is infinitely complex and infinitely detailed with infinite outcomes. Or in other words infinite causes and effects.
So in the end the best advice is still, just do it. As long as you don’t do anything foolish, or you are incompetent to perform the task. So for that reason, always prepare yourself for anything you do by doing proper research and preparation, and in the end you can have confidence in your own knowledge and experience. And also always have confidence in your ability to think on your feet and solve new problems as they arise.