Dr Nick Norwitz is a man who knows his eggs. Baked, fried, devilled or scrambled, the former Oxford academic now Harvard medical student has enjoyed them in all manner of ways recently. After all, when you set yourself a target to eat 720 eggs in a month – the equivalent of one egg an hour for 28 days – it`s important to find ways to achieve variety.
However, even more surprising than putting himself on this egg-freighted diet in the first place is the impact it’s had on the 28-year-old’s health.
After the month-long experiment, Nick’s levels of ‘bad’ low-density lipoprotein (LDL) cholesterol actually fell by 20 per cent, upending the popular view that too many eggs cause cholesterol to soar.
Talking exclusively to the Mail this week after completing the experiment – or should that be eggs-periment – Nick, who has a PhD in human brain metabolism from Oxford University and is now at Harvard University training to be a doctor, explained that he wanted to promote discussion and curiosity.
Dr Nick Norwitz, with boxes of eggs to keep him going during his month-long eggs-periment
He focused on eggs because of their association with cholesterol (‘and I like eggs’).
‘The logic is that if you have too much cholesterol in your blood it’s going to be from the food you eat – and eggs are high in cholesterol,’ he says.
What I was intending to do was amplify what is becoming increasingly common knowledge: that dietary cholesterol in the form of food such as eggs doesn’t necessarily increase your blood cholesterol, he adds.
The experiment was self-funded – as he points out ‘I can, in fact, afford to buy eggs’.
(US egg producer Vital Farms has since offered him a year of free eggs and he says: ‘I’m more than happy to accept. Medical school is expensive.’)
Ask most people and they’d probably say: ‘Eggs are bad for cholesterol’. But over the past several years this advice has been dramatically revised, even if the message is still to filter through.
In fact it’s now known that almost 80 per cent of the cholesterol in our body is made in the liver and recent studies suggest that eating eggs if you’re otherwise healthy won’t raise your cholesterol levels or increase your risk of heart disease.
For instance, earlier this year researchers from Duke Clinical Research Institute in Durham, North Carolina, found that people who ate 12 eggs per week had similar cholesterol levels after four months compared to those who ate fewer than two.
Cholesterol is a natural fatty substance produced by the liver and we need some in order to build cells. LDL is considered ‘bad’ because it can build up as plaque in arteries, increasing the risk of heart disease and stroke.
Dr Nick Norwitz says the point of eating 720 eggs in a month was to ‘promote curiosity’ about the issue
While our main source is the liver, cholesterol is also found in foods: one large egg has about 186mg, all in the yolk. So why does the cholesterol in eggs not cause problems?
The theory is that eating foods containing cholesterol triggers the release of the hormone cholesin, which travels to the liver where it binds to a receptor, signalling it to produce less LDL.
(This is different from foods rich in saturated fat, which stop the work of receptors that take the cholesterol out of the blood and into the liver, where it’s broken down.)
‘Eggs have had a bad rap,’ says Nick. ‘The logical fallacy is if you have cholesterol in your blood then it must be coming from things you eat – and because eggs have high cholesterol, you need to reduce your egg intake. But actually the body is very good at regulating things like cholesterol from food.’
Before his experiment earlier this year Nick – whose cholesterol levels were normal – hypothesised that consuming the 60 dozen eggs would not increase levels of bad cholesterol by the time the month was over. He hit on the number aware of the social media hook (an egg every hour of the day and night).
The National Institute for Health and Care Excellence (NICE) suggests that people who are at risk of developing coronary heart disease should limit their cholesterol to 300mg per day. Nick consumed about 4,750mg daily.
During the experiment he ate just two meals a day: between 10am and 11am, and then around 6pm.
Each meal consisted of 12 eggs. His culinary inventiveness included cooking with all kinds of fats such as macadamia nut butter, scrambling eggs with olive oil, capers and anchovies – with no planning ahead, but using whatever was in the fridge.
Alongside the eggs, he also ate protein such as meat and fish, but kept his diet low in carbohydrate.
‘The only rule was that for the first two weeks I was on a very low-carbohydrate diet of less than 20g a day – which amounts to no more than an apple,’ he says. ‘After two weeks I increased that to 60g a day – which is like two bananas.’
Nick explains that the theory behind this is that on a low-carbohydrate diet levels of LDL tend to surge because your body starts to burn fat for energy instead of carbohydrates. But when you add some carbohydrates, LDL levels fall faster because you’re getting more energy from carbs. This, he says, explains why his cholesterol fell by just 2 per cent in the first two weeks and then dropped a further 18 per cent after the second week.
Astonishingly, his routine and personal health appears to have been untroubled.
He says: ‘I slept a solid seven hours a night, ate 3,200 calories a day and didn’t gain or lose weight. I exercised, as I always have, for about one hour a day – usually resistance training. I am a high-energy person, if you like, and am pretty sporty. I’m also 5ft 8in with a slim build and my BMI [body mass index] never cracked 22.’ (That’s within the ‘healthy’ range).
And were there any side-effects, such as excess wind or constipation?
‘None whatsoever,’ he says, proudly. ’It seems my body adapted to eating lots of fat and protein. My girlfriend sleeps in the same bed as me and I would have been told about any gastric symptoms.’
But he is clear about not trying this at home – by his own admission, he’s always been someone who pushes boundaries. After breaking his leg at the age of 17 he insisted on still taking part in his hometown race, Boston Marathon, albeit on crutches (‘my mom wasn’t happy’).
And though he did the egg diet without any guidance, his previous experiments – which have been supervised – included eating 12 Oreos a day with a high-protein diet for 16 days to demonstrate the carbohydrates in biscuits could lower cholesterol better than taking statins. His LDL plummeted by over 70 per cent. (He stresses his role was not to encourage people to eat Oreos or stop taking statins, just to understand the impact.)
‘I also have a PhD in metabolism – I know about medicine and I know what to monitor,’ says Nick. ‘I’m not suggesting people do this or get between a patient and their physician (doctor).’
Indeed, as news of Nick’s egg study has spread, experts have weighed in with their concerns.
‘I think it is madness to do any of these crazy diets,’ says Dr Glyn Thomas, a consultant cardiologist at the Bristol Heart Institute.
‘The advice we give patients is there’s no such thing as healthy foods – only healthy diet. Being mindful of a healthy diet, exercising three times a week, giving up smoking and restricting alcohol is more meaningful than advice given ten years ago about avoiding eggs, dairy, cheese – animal fat traditionally seen as increasing cholesterol.’
And while Professor Sanjay Prasad, a consultant cardiologist at the Royal Brompton Hospital in London, says there isn’t a consensus about a daily egg limit, ‘in my view seven eggs a week is a sensible amount for a healthy person and four to five for someone with risk factors such as diabetes and heart disease’.
He adds: ‘When you eat food with cholesterol, that cholesterol can be deposited in blood vessels – high levels of which can lead to heart disease. The other thing is that chemicals in egg yolk can be metabolised to create a substance called Trimethylamine N-oxide which may sometimes cause inflammation of the heart vessels. That’s why I think no more than seven per week makes sense.’
Nick says the point of his experiment was to show people they didn’t have to shy away from eggs. ‘I wanted people to discuss the levers that can affect cholesterol in different individuals and promote curiosity,’ he says.
His egg-fest has not put him off eating eggs and he still has around six a day.
‘To me, choosing a breakfast meal based on eggs, which are filled with nutrients, is a better option than many standard carbohydrate foods that will spike insulin and promote fat growth,’ says Nick.
‘In my view eggs are good and if you are going to have them as a main protein source in a meal – four eggs in a meal such as breakfast is not a problem.’
And he says he still has the stomach for more such experiments – quite literally.
