Cristiano Ronaldo may have celebrated his 37th birthday last week, but there's no denying that the Manchester United superstar remains in unbelievable shape.

Still competing at the highest level at an age where many of his peers are comfortably settled in retirement, Ronaldo is truly one of a kind.

Maintaining such peak physical condition well into your fourth decade, though, is no easy task and the Portugal captain has been famed for paying strict attention to his diet throughout his career.

With no less than five Ballon d'Or trophies to his name, the approach has certainly paid dividends. How, though, would an average person fare if they were to follow Ronaldo's regime for a week?

Goal set that challenge to staff member Asad Raza recently - and the seven day period looked pretty gruelling for the 22-year-old.

At the start of his video diary for the week, Asad jokingly admits to "getting out of breath running up the stairs". Not the best starting point when attempting to mirror the lifestyle of one of the world's most famous athletes, to say the least.

LISBON, PORTUGAL - MAY 24: Cristiano Ronaldo of Real Madrid celebrates scoring their fourth goal from the penalty spot during the UEFA Champions League Final between Real Madrid and Atletico de Madrid at Estadio da Luz on May 24, 2014 in Lisbon, Portugal. (Photo by Lars Baron/Getty Images)

Asad's task for the week was split into two elements. Firstly, to follow Ronaldo's typical daily diet and secondly to mirror his workout regime.

Of course, he wasn't going to rock up at Carrington and start training alongside Ralf Rangnick's side, but he matched Ronaldo's exercise schedule as closely as possible.

Cristiano Ronaldo's daily diet

Back in January, The Sun published a summary of Ronaldo's reported daily diet. Using this as his guide, Asad took on the following menu each day for an entire week.

Breakfast

Cheese and ham, with low-fat yoghurt

Lunch (Number one)

Chicken and Salad

Lunch (Number two)

Tuna, olives, egg and tomato

Dinner (Number one)

Fresh swordfish and salad

Dinner (Number two)

Steak and calamari

It should also be noted that Ronaldo usually snacks on fresh fruit and avocado toast during the day, although this wasn't included in the challenge. The player's occasional 'cheat meals' were also ignored.

Initially, Asad was excited at the prospect of getting to chow down on steak every day. However, this enthusiasm quickly disappeared as the challenge progressed.

The problem with Ronaldo's diet, Asad discovered, was the lack of variety, together with a noticeable lack of carbohydrates.

The high protein diet clearly works for the superstar, who has a personal chef to prepare each of his meals.

MADRID, SPAIN - JULY 16: Cristiano Ronaldo of Real Madrid warms up while head coach Carlo Ancelotti looks on during a training session at the Valdebebas training ground on July 16, 2013 in Madrid, Spain. (Photo by Gonzalo Arroyo Moreno/Getty Images)

Asad, however, didn't have that luxury. In between meals, he also had to contend with a variety of workouts. From strength and conditioning work, to straight weightlifting and track spirits, Ronaldo packs a lot of activity into a standard week.

Despite obviously wanting to throw in the towel on a number of occasions, Asad made it through to the end of the challenge.

You can check out how he got on below.

Watch: Fan tackles Cristiano Ronaldo's daily diet and workout regime

By the end of the week, Asad looks like he never wants to eat another steak again. That said, he does report strength gains from the intense training schedule he's kept to during the challenge. He even reveals a desire to continue exercising, although likely not at Ronaldo-type levels.

Ronaldo's diet may not be particularly appealing, but after playing for nearly two decades at the peak of European football, its effectiveness cannot be denied.

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