I've found some for those age 12-19, and then 20 and up, but nothing specifically for the 20's. Obviously it seems obesity and overweightness are going up as age increases, so I was kind of interested for the rate of obesity/overweightness in those in their 20's... does anyone know where I can find such a thing?

I have no idea, have you goggled?

Yeah, I didn't find anything, but that doesn't mean it's not there... I'm not the best of googler's.

I went to Statistics Canada (obviously the numbers are for Canadians)

16.0 Total, 12 years and over
12.8 20 to 34 years
16.8 35 to 44 years
19.0 45 to 64 years
15.7 65 years and over

(sorry, it's not going to line up properly)

The catch is that they are self-reported, so the numbers may be low.

The above was for obese, the following are for overweight:

32.4 Total, 12 years and over
14.4 12 to 19 years
26.4 20 to 34 years
32.7 35 to 44 years
36.9 45 to 64 years
35.3 65 years and over

ETA: Source spreadsheets.... http://www.statcan.gc.ca/cgi-bin/cchs07-en.xls

This is US - but the age bracket is 20-39. This is per the CDC site on obesity - date 11/2007.

Among women, 41 percent of those aged 40-59 were obese compared with 30.5 percent of women aged 20-39. Women aged 65 and older had obesity prevalence rates comparable with women in the 20 to 39 age group.