MottiF makes some great points.
You are living for you not someone else.
Parents will always stick their nose in anything you do until you are out on your own so if you live under their roof its their rules for now but that doesn't mean what you eat when you are not at home.

John the OP is 18 and has no experience in the matter and maybe confused as to exactly what he wants. Maybe lighten up a little and help the kid to understand what he really wants or doesn't want.
He was asking questions and thats always where learning starts.

Why are the opinions of others so important to you is my question for you.
I was really skinny and hated being that way that was my reason.
I was tired of felling bad all the time was another reason.
Its not like you are going to get obese in a matter of months its going to take years to get there.
You are 18 now and in 3 to 4 years a lot of your current friends will be gone doing their thing and you will have a whole new set of friends so they will only know you as chubby

If you are worried about what others will say it sounds like you have a fantasy about gaining.
If wanting to be fat were a reality you would find a way to do it no matter what or what others thought.
Recognizing reality and fantasy are two different things is a start.
I started gaining to get back at a an abusive husband.
one time and the second time I wanted so bad to get fat that I did it and what others thought didn't matter.
Sure friends said things about my weight and my Mother still complains I am too fat.

Harry-Misty:
You can do smth like fbb3 on YT)))[/quote]

Yeah same here on the wait what thing.
I wish people would just take the time to actually type the words out. Some of us don't read in abbreviation. LOL

All fantastic responses and I hope they can help you navigate thru all that you are dealing with at the moment.
On the girlfriend situation I will say girls are very controlling of their boyfriends they will try to "groom" you to be the person they want you to be which is potential husband material.
Girls will test you everyday to see how much you can take emotionally.
I say this because like many girls I did those things.I ended up learning that was the wrong way to keep a guy.
Just remember if she is the same age as you she is just starting out too and learning as she goes just like you she is just as confused as you are she just will never show or admit it. Ask me again how I know it? LOL.
Again like others have said give yourself some space add some "you time" where you can be yourself and indulge in tour kink privately.
If your GF or family don't give you space tell them
you need some space and take it anyway.
They don't need to know what you do with your space and you don't need to tell them.
Try to not mention your kink to them because we know its out of the normal to them and they will never totally get it so don't force it on them.
The less you talk about it they less they will associate it with you.
Still indulge on your own time to keep your fantasies and kinks alive and enjoyable.

I hope I didn't come off as being critical and bashing you I was being honest because I have been there.
Lots of people now are too sensitive and take things so personally that if you say anything they don't like they get all defensive even if what they are reading is the truth and what they need to hear.
At 17 I thought I knew it all so I left home to play music. I got a rude wake up call and found out I knew nothing about being an adult or being on my own.
When I reached 21 I was a totally different person. In what I thought my outlook on life everything was almost 180 degrees different of how I used to be.
The main thing is be flexible and don't get stressed out. If people don't agree with you don't worry about it its no big deal they have a right to disagree because its a free country.
You believe what you want so they can believe what they too.

Why is it young people have such a hard time dealing with things?
Am I just insensitive or am I wrong?
The people around you aren't into it so not much you can do about that.
You will be out on your own soon hopefully so what your family thinks really doesn't matter
Girlfriends come and go so you may end up with one that has no problem with your fetish.
Don't get all stressed out over it in 5 years you will be a lot different a person because you will have matured a little and gotten to the point you don't care what they think.

You are very welcome glad I could help out.

Normal don't worry about it.
I had months where I ate like a mad woman and stayed the same weight.
I think it is your body trying to adjust itself to the constant barrage of calories.
I just kept eating large portions and eventually my weight started to pick up.
Those are called plateaus and it will pass.