They're regarded by many gym goers and health gurus as a super-food.

Yet ask a doctor about eggs, and they might tell you they raise your cholesterol levels and cause heart problems.

Eggs have been demonized for decades because their yolks are high in cholesterol, the fatty substance that builds up and damages blood vessels supplying the heart. 

But research in recent years has shown this has little direct direct impact on the amount of the substance that accumulates.

So to get to the bottom of whether eggs are bad or not, one man ate 720 of them in a month to see to see what happens to cholesterol levels.

Nick Norwitz, a doctorate student at Harvard University, found that contrary to the beliefs of many experts, his cholesterol levels actually dropped. 

After the month-long experiment that saw him eat the equivalent of 24 eggs per day his low-density lipoprotein (LDL) levels, or 'bad' cholesterol, fell by 18 percent.

LDL is considered to be 'bad cholesterol' because it can build up as plaque in arteries, increasing the risk of heart disease and stroke.

The other type of cholesterol, called high-density lipoprotein (HDL) or 'good' cholesterol, has the reverse effect however by helping to remove excess cholesterol from the bloodstream and transporting it to the liver.

Experts warn that having too much LDL could raise the risk of heart disease and other conditions. 

Dr Norwitz has a PhD in human brain metabolism from the University of Oxford and is completing his medical doctorate at Harvard University.

During the experiment, which has been viewed more than 160,000 times on YouTube, Dr Norwitz said he ate the eggs alongside his normal ketogenic diet of meat, fish, olive oil, nuts, dark chocolate, cheese and yogurt.

A ketogenic diet is a low-carbohydrate, high-fat diet that aims to shift the body from a state of using sugar as its primary energy source to fat.

He consumed the eggs scrambled, fried, deviled, hard boiled and as omelettes.

And despite the number he ate, Dr Norwitz says he is still not sick of them — and went to eat another 12 after speaking to DailyMail.com.

He ate the diet alongside his fitness routine, of about one hour of calisthenics every week. Calisthenics is a form of exercise that uses resistance training to build strength, and includes doing push-ups, pull-ups, squats, lunges and planks.

Dr Norwitz said: 'I hypothesized that eating 720 eggs in one month, which alone amounts to 133,200mg of cholesterol, would not increase my cholesterol. Specifically, it would not increase my LDL cholesterol.

'And, indeed, it didn't, not a smidge.'

He added: 'Even though my dietary intake of cholesterol more than quintupled, my LDL cholesterol actually dropped.'

He had to eat 24 eggs a day during the experiment, the equivalent of about one every hour if he didn't leave any time to sleep.

Revealing the diet plan online, he also showed an image of the more than 40 cardboard egg boxes he had collected during the experiment.

Eggs contain about 186 milligrams (mg) of cholesterol each. Other foods high in cholesterol include red meat and shellfish.

Hypothesizing why eggs won't raise cholesterol, some scientists explain: In the gut, cholesterol binds to receptors on gut cells which prompts the release of a hormone called cholesin.

This travels through the blood to the liver where it binds to a receptor called GPR146, which signals to the liver to produce less LDL, helping to maintain levels in the body.

After the first two weeks of his experiment, Dr Norwitz also decided to start eating 60 grams of carbohydrates per day.

For this, he focused on fruits like bananas, blueberries and frozen cherries, which he ate by dipping them in macadamia butter.

To hit the 60 grams target, he would need to eat the equivalent of two bananas a day, or 21 ounces of blueberries. 

He explained how eating more carbohydrates can help to reduce cholesterol levels further in the body.

In people on a low carbohydrate diet, levels of LDL tend to surge in their bodies because their system starts to burn fat for energy instead of carbohydrates.

But when someone eats more carbohydrates, the reverse happens — with LDL levels falling in the body because the person is getting more energy from carbs.

Commenting on the video, one viewer said: 'I clicked because I knew that your LDL would not increase and I want share this video with some of family that freaks out that I am eating all these eggs and meat!'

A second added: 'I’ve eaten eggs almost every day of my 67 years, through all the good/bad, never gave them up. And I’m in very good health, no doctors, no meds.'