If you have a particular weight goal that you want to reach, this diet could be the one for you if done correctly.
Heavyweight champion since 2015, Tyson Fury has been out of the ring for over two years now and his weight rocketed up to a massive 27 stone.
He too has a weight goal that he wants to achieve and it's all in the hope of an April showdown with Anthony Joshua which would definitely see two greats of the sport go head-to-head.
He has hit the gym hard and has already lost four stone since he decided it was time to go back to the every day grind.
His nutritionist, Greg Marriott told Sky Sports About the boxer's diet regime.
"He has lost nearly four stone. But it's not just about the weight, you have to be mentally right as well. A happy fighter is a dangerous fighter.
"It's about weight management at the moment. He's not training hard while he's heavy because he's prone to injury, so he's doing low intensity stuff and managing his diet. He's breaking into training easily.
"It's not about whatever weight he's at. It's about how he feels. Like Billy Joe Saunders, they had never [cut weight] properly before - killing yourself in the gym after a protein shake is not the right thing to do."
"Tyson is on a ketogenic diet. People say that's a fad diet, but Tyson is doing low intensity training at the moment. A ketogenic diet consists of high fats, minimal carbohydrates and some protein.
"He's on 3,500 [calories] per day. For example, if you have 1,000 calories but you expend 1,000 calories in the gym, you're on nil. When you try to cut weight [without enough calories] then you hit the wall, and you fatigue. This is where lots of fighters come unstuck. Tyson needs to be on 3,500 calories a day but, when he's expending 2,000 calories in the gym, he will need to be on 5,500 calories a day. You can then start cutting weight - this is the healthy way to do it.
Of course, unless your a sporting athlete like Tyson Fury, you won't be using or taking in as many calories as the boxer but if you want to kick start your January fitness regime, this diet could prove to be very useful.