How I lost 50 pounds this year

I lost 50 pounds this year (40 in the last 20 weeks). Here is what worked for me.

What worked for me

I'm not a doctor, this is just what worked for me. Please check with a doctor before starting any new diet or fitness plan.

Think in terms of the next week. I had a lot of weight to lose, and it was daunting. When I started to realize that losing just 10 pounds would be good, I got over the hump.
Don't get frustrated with plateaus. Weight loss comes in bunches. I would lose five pounds in a week and then nothing for the next two or three. Your body needs to get used to the new amount of food it's getting. Keep it up.
Exercise! I lost 20 pounds before exercising, but starting a regular exercise program kept up the momentum. I got a few sessions with a trainer, and I recommend doing that if you can. If not, concentrate on aerobic exercise at least three times a week. I am starting to do HIIT (High intensity interval training) -- see below for links.
Learn about portion size. I ate too much at meals (in addition to snacking) -- it's easy to overeat (even relatively healthy food), so measure and weigh everything until you get the hang of it.
Look for healthy options when you go out, and take some of your meal home with you.
Find a buddy to lose weight with. I had a friend to share recipes and tips, go out to dinner with, and generally talk about how it was going. Join Weight Watchers if you don't have anyone to lose weight with.
Cheat! I save up calories to have a great dessert every once in a while (or a nice dinner) -- I went on vacation for two weeks during the 20 week period and was happy that I came back the same weight, because I ate my way through Canada (but exercised every day too).

Weight loss sites I used

Weight Watchers: They concentrate on building sustainable eating habits. Not a fad diet. I didn't go to any meetings but spoke with friends that went for tips.
John Stone Fitness: This site was just for inspiration -- John took a picture of himself every day to track his progress while dieting and exercising. There is a picture practically every day for almost three years (and counting). His results are astounding. He also kept a food and exercise journal.
Free fitness journal: I kept track of everything I ate and all of the exercise I did. I highly recommend that you do the same -- here is a site and software to help, but you could just use Excel or paper.
Advice on Plateaus: Great tips on getting through plateaus. When I learned to accept these and be patient, I was able to change my lifestyle for weight loss.
USDA Nutritional Information: This site has a huge database of nutritional information.
MyPyramid: The USDA again with diet monitoring software. Also, lots of information on helping your child lose weight.
The Top 10 Tips on What Works and Why at The Diet Channel: Weight loss tips from The Diet Channel. They recommend watching portion size which is a major part of what Weight Watchers teaches you.
HIIT and Other Interval Training Methods: I've just started doing HIIT. It's something that you need to build up to, but so far I like the results.
HIIT from Muscle Media: Another HIIT article. Please work up to it -- don't just jump in unless you are in great shape.
Forget the Fat-Burn Zone: More info on HIIT (not for beginners)
Great tasting, low fat & low point recipes!: Low calorie recipes with weightwatchers points calculated for you.
MarathonGuide.com - Heart Monitor Training: I'm thinking of getting a heart-rate monitor as my training progresses. This is the best guide I found for using one.
The Hacker's Diet: A super-technical guide to losing weight. If you're an engineer like me, you might like it. Either way, read the Signal vs. Noise chapter to see the proper way to track your weight so that daily variance doesn't drive you nuts. It's easier to do that it looks (check out the pencil and paper tools to see the easy way to do it).
Heart Monitor Guide- Find The Best Heart Monitor For You: Comprehensive information about how to purchase a heart rate monitor
Hunger Management: 19 ways to fight food cravings and win the war on flab
Beginner's Training Guide for 10k: I am running in a 10k this March. Here is what I am using to train.