After all their trash-talking over whether people should skip breakfast -- the doc thinks you should, Mark says chow down -- they finally met up at an F45 Training gym in L.A. for the showdown.

The gladiators decided on a race to 59 push-ups -- for Dr. Oz's age -- but Wahlberg made it an even 60 ... and won by a few seconds. Pretty close, but take a look -- seems like the buff movie star was toying with the doctor a bit. Looks like Mark edged him out in form too, but keep in mind he IS 11 years younger. If ya need a reminder, check out the abs!

Afterward, Dr. Oz was feeling pretty good about his performance, and even thinks he might have gotten the better of Mark. Debatable, but he also tells us Wahlberg is trying out intermittent fasting and has come to the #cancelbreakfast table.

So, long story short ... the fitness challenge itself went to Mark, but Oz may win in the long run if Mark changes his daily diet. One thing's clear -- both of these guys really care about staying fit and healthy ... after the challenge they ran through an F45 workout.