mountain and consumes a mountain of food — that’s 4,500 to 5,000 calories a day during training — to fuel his 6ft 6in, 17st 12lb world champion frame.

On Saturday the IBF heavyweight king takes on Wladimir Klitschko, hoping to add the IBO and WBA belts to his collection.

Ahead of the Wembley showdown, Sportsmail’s Riath Al-Samarrai spoke to his nutritionist Mark Ellison to learn more.

Anthony Joshua consumes 4,500 to 5,000 calories a to fuel his day 6ft 6in, 17st 12lb frame

On Saturday the IBF heavyweight king meets 41-year-old Wladimir Klitschko at Wembley

Breakfast

Five eggs with a couple of avocados and a little bit of lime, seasoning, plenty of spinach and three pieces of toast. Blender full of fresh fruit with oats, yoghurt, milk and generous helping of honey.

Lunch

Big serving of pasta with vegetables, tomatoes and two full chicken breasts. Dessert is a large pot of yoghurt with fresh fruit, nuts, honey and granola. Big portions.

Dinner

Fish, sweet potato, quinoa, rice, fruit juice. Dinner tends to be protein based and includes dairy or nuts to fill him up before bed. He will also have a protein shake made from the protein casein which releases quite slowly throughout the night, aiding recovery.

Joshua works on the punch bag ahead of his big-fight showdown against Klitschko

The British heavyweight is aiming to become the heavyweight king at Wembley stadium

He will face Klitschko, who last fought in his defeat against Tyson Fury back in 2015

HERE’S HOW A CHAMP TRAINS

Speaking to Sky Sports, Anthony Joshua gave an insight into a typical exercise:

‘Get on the treadmill and put it up to 15 for three minutes and run as hard as you can. You do three minutes, then you have a minutes rest and hop back on.

Continuously do that maybe eight times and that will really get to the lungs and give you a good workout.’

Joshua typically goes through gruelling 98-day training camps ahead of heavyweight bouts

Next to a photo of him as a child, he joked that people often ask ‘how did you grow so strong’?

Cheat food

On rare occasions he will have an apple pie or apple crumble with custard. He also likes chocolate.

Fight day meal strategy

During camp the focus is on wholegrain carbs — brown rice, wholemeal pasta, wholemeal bread. On the day of the fight it switches to white rice, white pasta.

Will also switch to white meats, for ease of digestion. His prefight meal will be consumed three to four hours before entering the ring.

Secret weapon

Joshua typically takes in caffeine during training and enjoys coffee, but in fight week it gets cut right down. On fight night caffeine is re-introduced with the aim of giving him a jolt.

The IBF champion eats his final pre-fight meal three to four hours before entering the ring

Mark Ellison is the man tasked with making sure Joshua eats enough during his training camps

At Friday’s weigh-in, the 27-year-old tipped the scales at a career-heaviest 17st 12lbs 2oz

Nutritionist’s view

Ellison said: ‘I work closely with trainer Rob McCracken to figure out what the training methods are and what Joshua needs. He trains twice every day and those sessions could be a couple of hours. He’s a huge man who can take in 4-5,000 calories on busy days.

‘If you’ve got a little flyweight making weight, they might be on 1,000 calories a day, but I wouldn’t want someone going below 1,500. We are not strict — you try to create educated, independent athletes. Sometimes you create a monster. Joshua is very good — he is not fussy and sees it as fuel.

‘Most of the time he has his plan and he follows it. But he does crack me up when he says, ‘Is it really bad that I want to have a little bit of chocolate?’ Don’t worry about it, you’ve got to enjoy life. Mind you, he did wind me up the other day. He rang me and said, ‘I’ve just had six Easter eggs!’