Feeling Guilty
you know, just keep coming here for support. it works for a lot of us to be accountable. don't fret about what others think because you'll be the hot topic once the weight starts flying off. so get prepared for that part of it. my brother started jenny craig and does a walk at lunch time, briskly and he's lost so much weight jus****ching his diet and walking. like 25 pounds last month. that's like the surgery loss. he's incredible that way. so you're right. start with the good habits now and if you slip, so what, just start over tomorrow.
Any movement is good movement. Keep a journal..its fun to look back on.
I just opened mine back to the beginning (one year ago..) and noted that when I started, I could curl a whole 15lb DB :) (I now curl 60's) I also could do a killer 20 minutes at 120 strides on the eliptical. I now do 45 minutes @ 220.
One of the best motivators is looking back on how far you have come.
As for the food.. don't sweat it. Unless you eat non-stop all day long..you cannot eat enough at any sitting to gain weight. Just practice eating at your main mealtimes and get in all your water and protein... you will be fine.