What is enough?  Who decides?  Is it really you, or the voice of your
Mom, your Aunt, a teacher from school?  I grew up watching TV where
time was divided by the 1/2 hour or 1 hour program.  School also was
taught with time for each of the many subjects and my attention would
sit still only for that one hour training or less.  I learned that that
was enough.  I learned too what I could get away with and still get an
A.  What was enough for each teacher.  I learned about portions and
foods from my Mom who instilled a very strong ideal of what was
enough.  Who is right?  None of those people or trainings really. 

Enough is personal and I think depends on your personal desires and
goals.  You can train yourself to be satiated with less food just as
easily as more but it depends on ones willingness and idea of what they
would like.  If you are determined to feel left out and not enough then
there might be no satisfying you and you will make up ideas to support
your beliefs.  I've heard people say they lost weight on some regime
but only got to eat about one meals worth of food spread out over the
entire day.  For someone else who doesn't need to lose weight that same
amount of food might seem more than enough. 

So what are you willing to do?  Are you willing to enjoy more whole
foods?  Are you willing to cut down on amounts of food by a little to
get used to eating a little less?  These would be practices to start
implementing if you really would like to be smaller.  It's just as easy
to keep commitments to yourself as it is to break them.  Keeping them,
will boost your self esteem and give you the momentum to keep on
keeping them and challenge yourself further. 

Just like finding your capable of more in the gym, the pool, with your
guitar or even your time, you can find what is enough for you and what
you want to play with in your life.  I encourage you to keep playing,
make it fun and if you need it, get some coaching along the way.