Not as long as you drink a large diet coke to counter each big mac and fries. If you only drink one large diet coke it will only counter the one big mac and fry, so you’ll need a second one to counter the second big mac, so you may as well have a 2nd large fry too.
As a professional fat man, I can tell you right now 2 Big Macs with one large fry isn’t normally enough to break any kind of fast. You need to eat the two Big Macs, down a diet Coke, get a 20 piece McNugget, snort a bumb off each McNugget, dip in Hot Mustard (snort at your own risk), consume, wash it all down with another diet Coke, and then eat the large fry at your leisure to keep the high going, dipped in any remaining Hot Mustard.
Sadly, this was me this morning, minus the cocaine. I started my fast last night, exercised this morning, and started to stuff my face mindlessly afterwards. I restarted my fast because I didn’t know that diet coke and ice cream would have put me back into ketosis. /s
As always, it depends on the status of your metabolic pathways and if they are rate-limited at the time of ingestion— so… your glycolysis, glycogenesis, glyconeogenesis, lipogenesis, and fatty acid esterification, to name the major ones.
This tells you all you need to know.You are welcome.