Well we've all been there. I at my max was 195...I dropped 50 lbs in one year just by changing my eating and adding exercise. But then keeping it off was a challenge in college! I got back up to 160..then went to the academy for my work..dropped down agian to 145...and now here I am 2 1/2 years later up to 157
My best guess as to why it happened was lifestyle. Once I got out of the academy I was really active and kept running..until I had a hip injury. So I still went to the gym..got a boyfriend...cooked more, drank alcohol more..gained some.
Well single again for a few months..met the love of my life...gained a few more pounds going out to eat..cooking to impress..and still drinking far too many calories (don't worry I am not a lush, but those delish dark beers pack on a LOT of calories!)
So usually I work shift work..it changes evey 6 weeks..making it HARD to keep a normal schedule with fitness. My folks are in town and I haven't worked out since before they came a week and a half ago...my temp work detial has kept me on my butt ALL day since last May (going back to the field again this may..yet my duty belt is TIGHT!!

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So when it comes to changes into your lifestyle (work schedules, boyfriends, clubs) you have to find a new groove. It is so easy to get lazy. If I didn't watch what I am eating 80% of the time I would be screwed...but still slowly been packing on the lbs.
I am going to start P90x next week with my BF (so he says) and hopefully I can stay modivated since I don't have to drive 2 blocks to the gym haha! (yes I get THAT lazy).
I think designating a time, every day is important. I plan on doing it after work until my schedule changes again....I am way flabby and out of shape compared to 2 1/2 years ago..I could even do 2 pullups! NOT ANYMORE!
It is depressing...but ladies its easier to watch what you eat than modivate for exercise at times...do at least one to keep up with yourself. Don't give up and make goals here...we can all keep each other accountable!