One of the best ways to “trick” your body into ramping up metabolism is via a very high carb (4-500+ grams) and very low fat (50ish grams) cheat day. The science behind it is that your body’s excess energy signal, a hormone called leptin, drops as you diet and body fat is eliminated. To spike it back up, the best thing to eat is a ton of carbs. Some people even do two day carbs ups. But you limit your fat intake b/c you’ll be over maintenance calories and don’t want to turn those carbs into fat.
If you really want to bump things up, you can try to deplete all of your muscle and liver glycogen by doing long sets of isolation exercises (basically 5 sets of 20+ reps at a weight that you’re close to failure on the last rep) and do two exercises per body part. This is typically called a depletion workout and primes your muscles to accept all of the carbs/glycogen you’re going to give them. I followed this protocol for a while, doing a standard ketogenic diet during the week and then a weekly or biweekly carb up.
Also, during a carb up, if you want to keep the scale from moving way up, limit your liquid intake, or you’ll have several pounds gained from water retention.
Nice!
Sounds like a rapid fat loss diet or PSMF (protein spring modified fast).