Dr. David Unwin has been a general practitioner in a working-class town north of Liverpool since 1986. When he started, the practice had no cases of type 2 diabetes in anyone under 55. Today, he routinely sees patients in their twenties with the disease. The condition used to be called maturity-onset diabetes; the name had to be changed because it no longer described who was getting it.
Unwin, named one of the United Kingdom’s ten most influential GPs in 2018, calls what he is watching “a pandemic of poor metabolic health.” He has spent the last decade keeping one of the most carefully tracked real-world datasets on dietary intervention in primary care. What it shows is that most of the metabolic disease moving through the developed world is reversible — if caught early enough.
The Liver That Should Have Been Pink
Roughly one in three adults in the developed world now has fatty liver disease. The condition is silent. A healthy liver is the colour of fresh meat; a fatty liver is yellow and enlarged. Most people walking around with one have no idea.
The mechanism, once laid out, is straightforward. Carbohydrate of any kind — sugar, but also bread, rice, pasta, potatoes, cereal — is digested into glucose. The pancreas releases insulin to clear it into cells for energy. When the supply consistently exceeds what the body needs, insulin diverts the excess into storage as fat. Some lands on the waistline. A great deal is stored, less visibly, in the liver. Unwin describes this as having happened to him: a heavy biscuit habit, a growing waist he assumed was middle-aged spread, and a liver filling with fat that he did not know about.
Fatty liver itself interferes with insulin’s ability to do its job. The result is insulin resistance: the pancreas has to produce more of the hormone to achieve the same effect. For a while, the system compensates. Blood sugar reads normal. Nothing on a standard health check looks alarming. Professor Roy Taylor at Newcastle University has called this stage the long silent scream from the liver — and you can have it for about ten years before anything announces itself. What eventually announces itself is the pancreas giving up. By the time type 2 diabetes is diagnosed, the underlying disease has been in motion for the better part of a decade.
Five Litres of Blood, One Sugar Cube
The most striking image Unwin uses is a question. The average adult has about five litres of blood. How much sugar should be in it at any given time? Most people guess a cup. The answer is roughly one sugar cube — about four grams of glucose dissolved across five litres of fluid. That is the entire normal supply, regulated to that level minutely. A ripe banana delivers several times that amount in a few minutes. For someone with healthy insulin function, the surplus is cleared. For someone with insulin resistance, the result is a spike, a crash, and hunger an hour later. Repeat across cereal, muffin, sandwich, snack, and pasta, and the cumulative effect is the metabolic profile that fills Unwin’s clinic.
The trick that has done more than anything else to make this visible to patients was developed for ten-minute GP appointments. The scientific measure of how a food affects blood sugar is glycaemic load, expressed in grams of glucose, which nobody understands. So Unwin recalculated it in teaspoons of sugar — four grams each. A bowl of plain cornflakes, no added sugar, no milk: eight teaspoons. A medium baked potato: nine. A 150-gram serving of boiled white rice: ten. The chocolate bar most people would assume was the worst on the table: seven and a half. The infographic is not copyrighted, has been translated into thirty-five languages, and is freely distributed by the Public Health Collaboration, the British charity Unwin co-founded a decade ago.
Starch Is Glucose Holding Hands
The conceptual move most people have not made is the one between sugar and starch. I know not to have sugary things — I’ve given up sugar in my tea — and I don’t understand why my blood sugar is so high is, Unwin says, the single most common thing his patients say. Starchy carbohydrates are, in his phrasing, “glucose molecules holding hands.” Digestion breaks the bond; what reaches the bloodstream is glucose. Every four grams of digestible carbohydrate is broadly one teaspoon of sugar by the time it gets there. Once that arithmetic is internalised, the reasons people get caught out — the slice of brown bread that delivers three teaspoons of sugar, the bottle of barbecue sauce with thirty, the glass of fresh orange juice that hits the bloodstream as fast as a soft drink — stop being mysterious.
What the Data Actually Says
Since 2013 Unwin has been recording baseline and follow-up metrics on every patient willing to try lower-carbohydrate dietary changes. The numbers, since replicated by clinicians in Australia, New Zealand, and North America, are what make the rest of the story actionable. Of patients with prediabetes who go low-carb, ninety-three per cent return to a fully normal blood sugar, and the result holds on follow-up over years. Type 2 diabetes itself, once formally diagnosed, is harder to reverse but far from intractable: Unwin has now taken one hundred and fifty-seven patients into drug-free remission. He counts them by number.
UK government data indicates that every year of poorly controlled type 2 diabetes costs roughly one hundred days of life expectancy. The leading cause of death is no longer cardiovascular: eight cancers are now strongly associated with the disease, and cancer is a rising cause of mortality among diabetics. Unwin also cites figures suggesting every UK taxpayer pays an additional seven thousand pounds a year in tax to fund the downstream consequences of ultra-processed food consumption — two-thirds of which is not drugs, but lost tax revenue from people too ill to work.
The Piece of String
The tools required to know where you stand are nearly free. A piece of string the length of your height, cut in half, should comfortably go around the widest part of your waist. If it does not, the fat is in the wrong place — abdominal fat is the metabolically dangerous kind — and the conversation about insulin resistance has already begun whether you have heard about it yet or not. A continuous glucose monitor, which costs in the order of thirty to fifty dollars, will tell you within an hour what any specific food does to your blood sugar. Once you have seen the spike on your phone, Unwin notes, you cannot unsee it.
The intervention is not exotic. Build the meal around protein. Add green vegetables made palatable with whole fats. Treat anything from a packet with suspicion. What is striking is how decisively the long-term clinical data favours this approach, and how unfashionable it remains. The advisory tradition that built the modern food pyramid was the one Unwin himself believed and prescribed for the first twenty-five years of his career. He is also a person with type 2 diabetes. The path he describes is the one he had to walk himself — with results he has tracked, published, and put in the public domain for anyone willing to look.
The long silent scream from the liver does not have to end where the textbook says it does. But somebody has to hear it first.
Based on a conversation between Dr. David Unwin and Steven Bartlett on The Diary of a CEO. Dr. Unwin’s teaspoon-of-sugar infographics and the Public Health Collaboration’s educational materials are freely available in 35 languages.
Published for educational purposes by CI Mavericks. This article does not constitute medical advice. Please consult a qualified healthcare professional regarding your individual health needs.