Bryan Kohberger Sports Much Plumper Look in Throwback Photos

Bryan Kohberger looked like he swallowed one too many burgers when he was younger ... because he was a lot beefier back then compared with his much slimmer frame now.

Check out photos that recently surfaced on Reddit ... they show the convicted mass killer as a pudgy adolescent ... and he's even smiling in one pic, something we have almost never seen from Kohberger during his 3-year murder case.

Unclear exactly when these pics were snapped, but he could’ve passed for your average Joe -- like we said, he's cheesin' hard with a big toothy grin for the camera.

Clearly, Kohberger wanted a thinner version of his killer self, 'cause over 6 years ago Bryan ditched his old diet and went full vegan ... a drastic overhaul that probably accounts for his gaunt look he's best known for today.

Ironically, after embracing the vegan diet which preaches compassion, Bryan went on to commit the merciless slaughter ... butchering 4 University of Idaho students in their off-campus home in November 2022.

He ultimately pled guilty to the four murders, striking a deal that spared him the death penalty, but locked him up for life without the chance of parole.