The new boxes list each spongy yellow cake as having 135 calories and a weight of 38.5 grams. Right before it went out of business, the predecessor company said Twinkies were 150 calories per cake. Photos of past boxes online also show the weight to have been 42.5 grams per cake.
Hannah Arnold, a spokeswoman for Hostess, said in an email Monday that the size change was made in "mid-2012" by the predecessor company.
The shelf life of Twinkies is now 45 days, up from 26 days. Arnold said the longer shelf life was made by the predecessor company right before it went bankrupt.
The treats have been off shelves for almost eight months, since Hostess closed its plants and said it was going out of business in November following an acrimonious fight with its unionized workers. Hostess workers said the company failed to invest in updating its product. The company said it was weighed down by higher pension and medical costs than its competitors, whose employees weren't unionized.
Twinkies and other snack cakes were purchased by private equity firms Apollo Global Management and Metropoulos & Co.
The Associated Press contributed to this report.