We blamed the plate, and the chair got away

  Early action on diabetes means checking two things: your blood sugar, and your certainty.

COMMENT | JONATHAN LATIM | On Sundays across Uganda, lunch arrives the way it always has: Matooke with binyebwa, posho with beans, karo with eshabwe, and layata with boo. It is the food of home, the food many of our parents and grandparents grew up on.

In July last year, a front-page headline linked the rise in diabetes to Matooke and kalo. Within a day, the Uganda Diabetes Association pushed back. The study behind the story, it said, had not shown that our staples cause diabetes. Most of them, including Matooke, sweet potatoes, yams, and cassava when it is not ground into flour, are low or moderate on the glycaemic scale. The real risks, it argued, are highly processed foods and foods high on that scale: sodas, chips, sugar, white rice, even posho. That is the same posho that shares so many plates with beans.

Many of us picked a side. Others shrugged: ‘It is not the food, they said, it is how much we eat and how little we move. Every position had one thing in common. It rested more on conviction than on measurement.

Here is roughly what has been measured. Researchers at St Francis Hospital Nsambya gave twelve adults, six without diabetes and six with type 2 diabetes, three common breakfasts (katogo made with Matooke, bushera, and tea with bread) and took their blood over the two hours after each. The katogo gave the highest blood sugar response. The researchers chose traditional portions they considered equally filling, not equal in carbohydrate. So the katogo carried about 125 grams of carbohydrate, nearly three times the tea and bread and more than four times the bushera. And their katogo was green bananas boiled with tomato, onion and a little butter, not Sunday matooke steamed in leaves.

Three breakfasts of evidence. More than a year of opinions.

Same plate, different body

If our staples are guilty, how did our parents and grandparents eat them so often? If they are innocent, why might the same plate land differently today?

Part of the answer may lie not on the plate but in the body eating it. Earlier generations spent much of the day outdoors and on their feet: digging, fetching water, walking to the market and back. Many Ugandans still do. But in our towns, many of us now drive, take a taxi or a boda boda, and spend much of the day indoors, in a chair. Working muscles pull sugar out of the blood, so a body that moves all day handles a heavy meal differently from one that sits. The plate looks much the same. The life around it does not.

Uganda’s national health surveys have been watching the chair. In towns, about a third of adults said in both 2014 and 2023 that they sat for more than four hours a day. In the countryside, the share climbed from about a quarter to about three in ten, even though nearly all adults say they still get the recommended amount of weekly physical activity. The countryside is also where raised blood sugar rose most clearly. The chair is not only an office problem. The surveys do not show that sitting caused the rise in blood sugar; they show why the chair belongs in the question. Yet the chair barely featured in last year’s argument.

Many of us were also raised on a rule: after eating, sit down and let the food settle. We were told it was so we would not be sick from running about on a full stomach. Most of us carried the rule into adulthood without asking what it costs. In a trial in New Zealand, adults with type 2 diabetes who walked for ten minutes after each main meal had lower blood sugar after eating than when told to walk the same total time at any hour of the day. The biggest difference came after the evening meal. For adults with type 2 diabetes, at least, the old rule may carry a measurable cost. Whether it holds for everyone else is one of the questions Uganda still needs to answer.

That idea, that the body matters too, should unsettle both camps. If it holds, no staple is simply guilty or simply innocent. A food does not have one fixed effect. It depends on how much is served, how it is cooked, what it is eaten with, and how the person eating it lives.

How it is cooked matters more than most of us assume. Uganda’s own carbohydrate-counting guide, drawing on international tables, notes that Matooke, potatoes and yams cooked in their peel have a lower glycaemic index than the same foods peeled, and the Diabetes Association’s own statement drew the line at cassava flour.

So ask yourself. Is mashed Matooke the same as Matooke left whole? Is boiled cassava the same as cassava ground into flour? Is yesterday’s rice, warmed up, the same as rice fresh from the pot? Does a walk after a meal change any of it? In the searches behind this article, I found no published Ugandan study that answers these questions in Ugandan bodies.

A disease that does not knock

This matters because type 2 diabetes builds quietly over years, and for most of that time a person feels fine. Blood sugar that stays high can damage blood vessels and nerves throughout the body, and it does so in silence. Diabetes is the diagnosis, but the burden is a cascade: heart attack and stroke, kidney failure, blindness, wounds that fail to heal and can end in amputation, and complications in pregnancy.

The International Diabetes Federation estimates that nearly three in four adults with diabetes in sub-Saharan Africa do not know they have it, the highest share of any region in the world. In Uganda, the same national health surveys, which tested people’s blood rather than simply counting diagnoses, found that the share of adults with raised blood sugar more than doubled between 2014 and 2023.

So many people learn the news late, when the damage has begun. The cruellest feature of this disease is that its early stage is its most treatable stage, and the one most easily missed.

This year’s World Diabetes Day, November 14, carries the theme “Early action on diabetes.” It is the right theme, and for type 2 diabetes the arithmetic is plain. The cheapest case is the one prevented. The next cheapest is the one found early. The most expensive is the one found late.

The first step is simple: ask a health worker whether it is time you were tested, especially as you get older, if you carry extra weight around the waist, or if a parent has diabetes.

What it would take

These questions can now be followed into daily life. A small sensor worn on the arm can track blood sugar every few minutes, day and night, while a person goes about their life. Such sensors have already been worn in Uganda: by young people with type 1 diabetes, by adults attending diabetes clinics at rural and urban hospitals, and by pregnant women.

My company, KRINO Systems, has drafted a proposal for a Ugandan-led study of these questions. Ugandan investigators and ethics reviewers would decide whether it goes ahead, and in what form. As drafted, it would measure common dishes, cooked in different ways, and whether a short walk after eating changes the response. It would include adults without diabetes, with prediabetes and with type 2 diabetes, on supervised mornings and through two weeks of ordinary life. The company is also designing a phone tool for people managing their blood sugar, which the study’s findings would inform. That is my stake.

My other stake is personal: members of my family have lived with diabetes, and I believe it shortened some of their lives.

For a study’s results to matter, they must survive the people who dislike them. So the plan would be registered publicly before anyone enrols, and the results published whatever they show, even if they show that our staples raise blood sugar far less than our arguments assumed.

A study of how blood sugar rises after a meal will not, on its own, prove what causes diabetes over a lifetime. What it can do is replace some of our certainty with measurement.

Your blood sugar can be checked at a health centre. Your certainty can be checked at your next meal.

Which of the two have you checked lately?

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Latim is the founder of KRINO Systems and leads the GlycoPilot research program. glycopilot.health

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