In the classic movie Star Wars Episode IV: A New Hope (you know, the first one), Luke is getting schooled in the ways of The Force by Jedi master Yoda when Yoda tells him to use The Force to levitate his X-Wing fighter out of a swamp. Luke is skeptical, to say the least, and tells Yoda, "Alright, I'll give it a try." Yoda's response is a classic within a classic: "Try not. Do. Or do not. There is no try." (Luke gives it a shot but fails.)
For many years (it came out in 1977???), I thought this was giving people an easy cop-out: "I don't think I can do it, and there is no 'try,', so forget it." In psychology, this is known as "self-efficacy": your belief in your ability to do stuff and reach goals. From the Wikipedia link:
People generally avoid tasks where self-efficacy is low, but undertake tasks where self-efficacy is high. When self-efficacy is significantly beyond actual ability, it leads to an overestimation of the ability to complete tasks. On the other hand, when self-efficacy is significantly lower than actual ability, it discourages growth and skill development.
Only relatively recently did I reinterpret Yoda's counsel, at least relating to cumulative objectives like wanting to be stronger, faster (StrongFast!), leaner, healthier, etc. Even if we refine vague objectives to meaningful goals ("lose 3 inches off my waist in 6 weeks", "add 50 pounds to my deadlift in 12 months"), they're still cumulative. That is, we can't do one thing one time to achieve it. For these, "there is no try" is brilliant!
You don't get leaner by "trying" anything, you get it by "doing" things. You might eat to 80% full (Hara hachi bu) six days a week, or do HIIT (High Intensity Interval Training) three days a week, eat five servings of vegetables every day, etc. There are many things you can do to reach your goal, and that's the point: you have to do things.
This is the difference between outcome goals that focus on a result (like losing three inches off your waist) and performance or process goals that focus on doing things (like eating to 80% full). An outcome goal without any process goals is not likely to be reached.
If your goal is to lose three inches off your waist, what are you going to do to make it happen? If you're "trying" to eat one meal a day (a Very Low Calorie Diet using Intermittent Fasting), your self-efficacy is likely to be very low and, like Luke, you're probably doomed to fail.
Telling yourself to "suck it up" (or having a "coach" or "friend" tell you) isn't going to help in the long run (and possibly not even in the short run). You don't need more motivation; you need to do things you're reasonably confident you can complete (high self-efficacy).
This doesn't mean you won't need to make some effort to do things. You just need to be reasonably confident they are things you will be able to do for as long as you need to do them. You might need some help from a coach, friend, app, or whatever...that's fine. Having supportive accountability can give your self-efficacy a boost. ("I know I can do it because I'm not in this alone!")
Now, astute readers (that's you!) will notice that Yoda's words of wisdom were applied to a single task: lifting the X-Wing out of the swamp. So yeah, you can "try" to do one deadlift (or one set), or "try" to eat to 80% full at one meal. (Jack Nicholson tried.) Stupid Yoda.
This is one time where "I was taken out of context!" is a good thing. When it comes to reaching your goal, there is no try. You need to do (the right) things. And believe you can do them. After Luke failed in his "try," Yoda used The Force to levitate the X-Wing.
Luke: "I-I don't believe it."
Yoda: "That is why you fail."
Believe it.
"Try not. Do. Or do not. There is no try." Yeah. What he said.
Be seeing you.
-gary