THIS HARVARD DOCTOR BELIEVES WE’VE BEEN GETTING CHOLESTEROL ALL WRONG
“Stick to the end of this video and you’ll have enough knowledge to give your cardiologist a heart attack,” Dr Nick Norwitz tells his one million social media followers. Into the hotly debated arena of cholesterol, statins and how to prevent cardiovascular disease leaps this 30-year-old YouTuber, a Bostonian who once put away 720 eggs in a month, ate 1,000 sardines in 30 days, and has a marathon personal best of two hours 45 minutes.
Norwitz calls himself a “metabolism influencer”, but he’s no Instagram quack, having a PhD in physiology, anatomy and genetics from Merton College, Oxford and medical degree from Harvard. He inherited his interest in medical matters from his parents, both doctors, but with an urgent, personal twist: Norwitz was diagnosed with ulcerative colitis at the age of 21 and, later, seriously high cholesterol. He was to find the answers to his health issues in a ketogenic diet, more on which below.
Interestingly, Norwitz – who on May 9 will be appearing as a speaker at the Smart Ageing Summit, led by the Oxford Longevity Project – believes our views on cholesterol are outdated. “These opinions are supported by the persistence of cardiovascular disease as a leading cause of mortality, despite the enormous financial and intellectual resources devoted to it,” he says, adding that many cardiologists have “become somewhat monomaniacally focused on the biomarkers LDL cholesterol and APoB (a protein found on LDL particles) as a causal driver of cardiovascular disease. This results in a kind of ‘missing the forest for the trees’ phenomenon.”
Norwitz joins a growing number of experts who feel the relationship between cholesterol and heart disease is not as straightforward as conventional medicine suggests, and that statins are overprescribed. “That’s not to say these blood markers play no role: they do,” he says. “Nor am I saying ‘don’t trust your doctor’, but I do believe these factors are overemphasised relative to other important factors.
“Clinical medicine tends to lag behind cutting-edge science by a decade or more,” says Norwitz. “We are now gaining a more refined understanding of how statins work in the body, including their interactions with specific pathways and channels.”
Why LDL cholesterol isn’t always bad
Norwitz calls the denigration of LDL cholesterol a “twisted narrative. Research increasingly shows that the causes and consequences of high cholesterol vary enormously across individuals,” he says. “Firstly, high LDL isn’t always ‘bad’. What we really need to be concerned about is plaque, which leads to the narrowing of arteries and increases risk of cardiovascular disease. There are people who develop plaques on their arteries with low LDL, and some with high LDL – some in excess of 18 mmol/L [millimoles per litre] for more than a decade – who have no plaques at all.” He says this should make us ask questions, at the very least.
Norwitz has lived with what is usually considered to be dangerously high total cholesterol (above 18 mmol/L) for seven years, but a recent analysis has shown he has absolutely no plaque (calcified or soft) in his arteries.
He contends that there is enormous variability as to why people have elevated cholesterol. “Is it driven by a genetic mutation? Does it arise in the context of metabolic dysfunction and obesity? Or is it something else entirely?” he asks. “The problem is that it’s very hard to have a conversation in the nutrition space – scientists can be very tribal. People weaponise data to support a preconceived narrative. Ultimately, we are just trying to provide clarity.”
Norwitz points to a meta-analysis of randomised controlled trials published in the 2024 American Journal of Nutrition which shows that it is often the leanest, healthiest individuals who experience the largest increases in LDL on low-carb diets. Conversely, those with obesity and metabolic dysfunction tend to see decreases in LDL cholesterol when they cut carbs, even when increasing their fat intake. “That runs counter to conventional wisdom and it raises two critical questions: why is this happening, and what does it mean?
“These insights will eventually help us move toward more precise, individualised therapies with better benefit-risk profiles,” he says. “But it will take time for clinical practice to catch up.”
Are statins overprescribed?
And what of statins, drugs habitually prescribed to lower cholesterol? According to the National Institute for Health and Care Excellence’s website, an estimated seven to eight million adults in the UK take the drugs to reduce their risk of heart attacks and strokes, with usage almost tripling over the past decade.
Norwitz believes some of these prescriptions are made without sufficient thought. “I’m not saying nobody should have them, but I’m not saying everybody should,” he says. “Statins are a tool, like any other in medicine they have their place. But statins should be used with precision and it’s naive to assume we understand the full scope and long-term net impact of these drugs – especially in individuals who are otherwise healthy.”
“Otherwise healthy” is an important caveat. Norwitz accepts that statins can be life-saving for those who have experienced a serious cardiac event, for example. “But when you look more closely at the data, a pattern emerges,” he says. “Individuals who are metabolically healthier – those with lower triglycerides, higher HDL (“good cholesterol”), lower blood pressure and fewer features of metabolic syndrome – tend to derive minimal, if any, cardiovascular benefit from statins. Yet, they remain exposed to the same potential harms, which include the increased risk of diabetes and insulin resistance, and muscle mass loss.”
He cites research suggesting that statins can lead to reductions in GLP-1 levels – working the opposite way to drugs such as Wegovy and Ozempic, increasing appetite and leading to weight gain. “But we are just starting to understand this,” he says. “I would argue drugs should not be presumed innocent until proven guilty.”
Norwitz has personal experience with statins. At the age of 23, a routine blood test showed that his cholesterol had dangerously spiked – and he did not have familial hypercholesterolaemia (the genetic form of the disease). “I tried two different statins which caused muscle pain, elevated a muscle-damage marker and impaired my exercise in a blinded trial,” he says. “My arteries are perfectly clean: why should I subject myself to both the known and lesser-understood side-effects of statins?” He came off the drugs, and decided to address his health concerns with a low-carbohydrate, high-fat diet.
The role of insulin resistance
Norwitz has joined the growing number of experts who believe that a high-carb Western diet leads to insulin resistance, a condition which, in turn, raises the risk of cardiovascular disease. This, he feels, is where the longevity spotlight should shine.
“Insulin resistance is the metabolic fingerprint that our body is in metabolic disarray,” he explains. “This leads to altered signalling in and between organs such as your heart, brain and liver, and markers of metabolic syndrome, like low HDL cholesterol and high triglycerides. Type 2 diabetes is the ultimate evolution of insulin resistance, but you can certainly have insulin resistance without diabetes.
“Research, such as the Women’s Health Study published in JAMA Cardiology 2021, shows that insulin resistance is associated with a risk of cardiovascular disease that’s greater than that of high LDL cholesterol,” says Norwitz, who believes insulin resistance should be treated by diet, rather than drugs: particularly by cutting out refined carbs, sugar and ultra-processed foods, and eating more high-fat foods.
“The literature overwhelmingly shows cardiovascular risk factors improve on a well-formulated low-carb diet for those who are overweight, obese, or who have insulin resistance or metabolic dysfunction.”
How the keto diet can help heart health
The keto diet is “named for the metabolic state of ketosis where the body burns fat for energy, some of which is made into ketone bodies that fuel the brain,” explains Norwitz, who began following it after a personal health emergency. In the third year of his undergraduate studies, he developed ulcerative colitis, characterised by violent episodes of bloody diarrhoea, sometimes more than a dozen times per day. “This meant I had to give up many sports and social activities,” he says. “I developed severe exam anxiety – I was afraid a flare would strike and leave me rushing for the bathroom. As you can imagine, it also killed my social life.”
At one point, Norwitz weighed just 7st 2lb. “I tried lots of different diets, including plant-based, but it was the ketogenic diet that completely resolved my symptoms. It was life changing.”
Today, his diet breaks down like this: 79 per cent fat, 18 per cent protein, and just three per cent carbohydrate. “My net carb intake is below 20g a day,” he says. “This could translate as one small apple, a half a cup of cooked pasta, or one slice of white bread.” Instead, he eats foods that are high in protein and fats: pasture-raised eggs, tinned sardines, poultry, pork, organ meats – all entertainingly detailed on social media. He loves cheese: Manchego, feta, Roquefort.
At pains to point out that the keto diet isn’t just macho men mainlining lumps of red meat, Norwitz says, “You can eat fish and leafy greens – avocados, olive oil and nuts can be ketogenic.”
What about the warnings that the keto diet can increase cholesterol? “For the average person, eating saturated fat can increase cholesterol,” he says. “But whole-fat dairy, unprocessed meat and dark chocolate are saturated fatty acid-rich foods with a complex matrix that are not associated with increased risk of cardiovascular disease.
“The chain of logic – ‘this contains saturated fat, thus increases cholesterol, thus increases cardiovascular risk’ – is like saying that eating blueberries causes fatty liver because blueberries contain fructose.”
Ultimately, Norwitz hopes that readers will experiment, and not feel they are at “the end of the rope with conventional medicine. The objective is not to point fingers at your medical heroes. Be at the helm of your own health ship.”
Nick Norwitz will be speaking at the Smart Ageing Summit at Rhodes House, University of Oxford, on Saturday, May 9. Event info can be found at oxfordlongevityproject.org
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