That's a considerable amount of weight to lose in 7 weeks. Unless you're completely out of shape now and you're starting from scratch, it's not very likely that you'll lose that much weight and still be able to perform near your best. When losing weight and gaining fitness, you've got to compromise one to help the other. You have to choose what your goal is.
It sounds like your focus is on losing weight, which is fine. Two pounds a week means a 1000 calorie deficit per day. You will be really tired, cranky, and you'll have trouble focusing on anything else. You can get through workouts, but you'll need a lot of sleep to do it. I kept it up for months at a time, and I would regularly pass out on the couch as soon as I got home from every workout. If you time your nutrition really well you might be able to have enough energy to last until nighttime.
Another problem is losing that quickly makes it easier to bounce back right after. You lose all this weight, then when you finish your race everything stops, and you rebound right back to where you start. Been there, done that.
That said, the most effective trimming down that I've done has been done this year. I cut out alcohol for one month, and made a conscious effort to eat better. Not perfect. Not cutting out any foods. I was eating a wide variety of foods in reasonable proportions. It's harder than it sounds, but I figured out a good trick to stick with it. I'd ask myself before eating "do I need this?" Simple question.
If you're honest with yourself it makes it much easier. In that month I dropped five pounds, and kept it off for the two months since then. I'm going to do that again next month, then maybe once more before the holiday season. Then that's it. 15 pounds over six months, in a sustainable way. Also I'm in better shape and faster than I've ever been thanks to this. The first time I've had a long training block without trying to lose too much weight at the same time.
Your mileage may vary, but I would highly recommend scaling your weight loss goals back a bit, and instead concentrate on how you feel and improving overall.
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George Dedopoulos | @geodee | geodee.com | Team Atomica | Toronto Triathlon Club