I lost 70 pounds in 10 months by cutting my fat intake to less than 10 grams a day and drinking at least a gallon of water per day. Went from 40 inch waist to 33 in less than a year.
Mrs. ShibbOleth is now up to about a size 6, from what I can tell. I tried to buy her a silk dress last year around Christmas, but it was a 2 or 4, and she couldn’t fit into it so I had to return it. It seems from what people are saying here that it may be a mistake for a man to attempt to buy clothing for a woman. I just looked at the dresses and took a guess. Suppose it’s better that I didn’t guess too big. I am a bit larger than that myself, it would be interesting to try and compute men’s sizes into women’s sizes.
Um, GreatKingRat, doesn’t less than 10 grams of fat seem a little low to you? That doesn’t sound like the healthiest (or easiest to keep up) diet in the world.
I can SO identify with the OP. Since this Spring, I’ve put on about 20 pounds (due to college, me being lazy, sedentary job, etc.) Everyone says it isn’t too noticeable but I think they’re being nice. I sure as heck notice it. But I agree with all the situations that have been given. Start a diet that you can definitely keep up–that’s what I’m doing. Make it a lifestyle change. Don’t do anything that you won’t be able to continue doing after you’ve lost the weight (I liked the “get a dog” idea, btw.) Good luck, Oreo! Let us know how it goes. 
Ain’t nothin’ wrong with 14!!
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Clothing sizes have absolutely no correlation to weight, either.
I wear a Levi’s 550 jeans in either a snug size 12 or a baggy size 14. Don’t think that a 13 will fit, it won’t, for the reasons bluethree gave above. I have a sister that wears the same size(s) as I do, and we’re within 1/4 inch of each other in height.
My weight hovers anywhere from 195 to 205 lbs.
My sister hangs around in the 165 to 170 lb. range.
Right after my sister had her last baby her weight was up around 190 lbs. and the smallest jeans size she could fit into was an 18.
I weigh roughly 30 lbs. more than my sister, and we wear the same size in the same style in the same brand of jeans.
I just tell everyone that it’s all muscle.
I firmly believe that the number you see on the scale is meaningless.
The clothing maker chooses an “ideal size” for their line (usually a 6 or an 8), and designs their clothing around that size. They then add or subtract 1/2 inch to an 1 1/2 inches to the chest, waist, and hip circumferences to get the sizes up or sizes down from the original size. (BTW, sizes go up by 2, so one size up from a 6 is an 8. Odd sizes are “juniors” sizes, evens are “misses”.)((also, length doesn’t really come into it at all - so even if something should fit it may be entirely wrong due to how short or tall the woman is))
For most brands, you can get a hold of a chart that will tell you what each size means to them (and how they map small, medium, large, etc. onto their clothing sizes). And if you look at a bunch, you can see that they vary from brand to brand (and over time within the brand). So the same person may fit into a size 8 in one brand and a size 14 in another.
However, if you know that Mrs. ShibbOleth looks great in a certain dress that fits her perfectly, you can check that dress’s maker and size and shop for another dress by the same person in the same size and it will most likely fit her.