And just because the characters weren't making fat jokes doesn't mean there weren't plenty around. When the wedding party (pre wedding) goes out to eat together, Megan runs ahead of all of them to get into the restaurant. At the bridesmaids dress shopping she lifts the sitting couch and then flops over onto it, awkwardly and obviously in a sort of beached whale style.
Matt Lucas and sister Brynn played by Rebel Wilson are secondary characters so less seen, but when shown are portrayed as weird, bumbling, and unintelligent. The first time we meet Brynn she's gotten a free tattoo out of a van. When she shows Annie it's obviously infected and gross. Annie tells her to put a bag of frozen peas on it or something so Brynn goes to the freezer, gets a bag of peas, opens it, and pours them down her back. All I could do in the theater was facepalm.
I'd also like to point out the difference between the actual body type of Melissa McCarthy and the movie poster, in which Melissa has been visibly thinned in her waist, hips, face, and arms.