I'm very aware of body types and I want to ask you if you are aware of each?

Ectomorph
Mesomorph
Endomorph

An ecomorph typically has a fast metabolism very skinny.  They have a hard time gaining weight but have no problem losing weight.  

Mesomorph can either gain or lose weight easily

Endomorph gain weight easily but have a hard time losing it.  

i could go a lot more into each one but yes im aware of body types

There you go

If your grades are terrible, why don't you better them?

In a way, yes indeed. Genetical effects aside, I believe that obesity is often very close to drug addiction / has a very similar psychological basis, and just like drug addiction often indicates personal problems.

Just like taking drugs, eating is a very easy and reliable way to "feel good", if only for a very short time. It's something like the lowest source of joy, and especially people who currently have very few other sources of joy in their lives will be tempted to eat more than they need.

How did these "tricks" work out? I was in a very similar situation with my girlfriend once, and tried to motivate her to with similar tricks. In my case, they didn't work out at all - quite the contrary, she started eating even more. Which I believe was because no matter what I said and how nice it sounded, what I really meant was "I really wish you were thinner", and the more I started talking about the topic, the more she took it as me criticizing her, which made her feel even worse, and ultimatively caused her to eat even more. It's was a vicious circle.

So I believe your strategy is dangerous: You might win and your tactics will indeed give her the huge motivation push that these people need. But you could just as well fail, in which case you might make the situation even worse, both for you and your girlfriend.

If you want your girlfriend thinner, my advice would be not to directly fight her obesity. Because her obesity is probably just the visible effect of a personal problem(s) lying below; if you "solve" the problem(s) below, the problem(s) above will sooner or later disappear by itself.

Because they have a free will and choose to remain fat, of course.

I tend to put on pounds quick while unemployed (drinking/being lazy/over eating) and then drop it while employed. I probably should find a better job than manufacturing in USA that doesn't lay people off so much. A few years ago I put on 60-70 lbs in 6 months while unemployed and dropped 70 lbs after 10 months of being employed. This most recent time I put on about 40-50 lbs while being unemployed for 5 months and now have dropped 10-15 lbs since starting work in late Dec.

Well it's all about the power of will, i myself am really tall and in good shape i exercise every day and i actually have to gain some weight lol! but i have one bad habbit smoking :(

I'm 5'11 and 125 pounds at age 23. craaaazy skiny. I can imagine there are some fat people have the same issue I run into...

I eat 3000 calories a day, way more than I need to eat - I work consistently...but I can not gain weight! I should probably get my thyroid checked out or something. I'm an Ectomorph, I have and extremely hard time gaining weight.

If im standing right, you can see my heart beating through my chest. I hate it and am crazy self conscious about it. I bet some big people run into the same issue, but the on the opposite end of the spectrum.

im 6`0 285lbs lmao!!!

Im a fat athletic person, tbh i haven't been workin out our anything in a year and a half soi gained 50lbs! lol