The Flash star confirmed that he’s proud of himself for the work he has put in mentally and physically, and even previewed that Flash viewers are going to notice a difference in Barry Allen, presumably once The Flash finishes telling the stories that were planned to end Season 6 and gets going into Season 7 in earnest.
The pandemic gave him the motivation to start making changes to “be more present” and happy with who he is.
According to Grant Gustin, eating better and working out were part of his decision to break a cycle of not taking care of himself and deal with his anxiety.