Pity the poor carbs. They’ve had relentlessly bad press in the wake of the global “low-carb” movement. Once the backbone of every meal, carbohydrate foods have become the nutrition world’s favourite villain.
If you believe diehard, low-carb enthusiasts, a slice of toast is practically an act of self-sabotage. Pasta? It’s public health enemy number one. Bread, once globally revered as a “staff of life”, has fallen off its pedestal.
Beef, butter, broccoli and berries are saintly by comparison.
As with most food fashions, there’s more starch to this dietary story than sound bites on carbs suggest.
Carbohydrate joins protein and fat as the three macronutrients that are universally recognised as classes needed in significant amounts (relative to micronutrients) for human health. Their roles combine to produce energy, build and repair tissues, and support physiological processes.
Cape Town diabetologist Julien Trokis favours low-carb eating regimens, though he views demonising carbs as “somewhat simplistic”.
“Carbs are not inherently evil,” Trokis says. “The problem is not just that most people eat too many carbs. They also eat too much of the wrong kinds.”
He ascribes this to modern “Western” diets that are high in ultra-processed foods (UPFs) and refined carbohydrates that have little nutritional value. “The consequences,” he says, “have been devastating for health.”
Research shows that UPFs are major contributors globally to rising levels of obesity and type 2 diabetes (T2D), and complications that include heart attack, stroke, kidney failure, nerve damage, vision problems, limb amputation and certain cancers.
South Africa is no exception. About 40% of South African men and close to 70% of women are obese. Childhood obesity rates are high relative to other African and many developing nations and comparable to middle- to high-income countries. T2D levels are rampant among all ages in South Africa.
UPFs are also shown to have negative health effects separate from calories or nutrient scores.
A multinational study in Diabetes Care in 2024, led by Harvard Medical School scientists, followed more than 4,000 women for decades. Data showed that even when participants generally ate “well”, their UPF intake was enough to pile on extra kilos and increase the obesity and T2D risks.
UPFs come in many shapes, sizes and disguises and mostly share two features: they are industrially made and designed to be tasty. They are also deliberately engineered to be convenient, shelf stable and addictive. And they are distinctly unkind to blood sugar levels, weight and long-term health.
The list of UPFs is endless. Common forms are sweetened breakfast cereals, instant noodles, flavoured yoghurts, packaged breads, buns, biscuits, cakes, chocolates, energy bars and most fast-food items. Processed meats, such as polony, hot dogs, chicken nuggets, ready meals, frozen pizzas and “healthy” snacks, such as crackers, rice cakes and protein bars, qualify. So do soft drinks, fruit juice concentrates and flavoured milks.
UPFs share long ingredient lists of things you wouldn’t (or shouldn’t) usually cook with at home. These include emulsifiers, stabilisers, gums, artificial sweeteners, colours and flavour enhancers.
There’s no rocket science required to understand why carbohydrate foods in general, and UPFs in particular, are bad for health.
All carbohydrate foods, whether bread, pasta, rice, potatoes or French fries (“slap chips”, as South Africans call them), turn to sugar (glucose) in the bloodstream, says Trokis. The body responds by releasing insulin, the hormone that moves glucose into cells for energy.
Constant insulin stimulation encourages fat storage and makes appetite control difficult. It causes “vicious cycles” of overeating, weight gain and eventual insulin resistance, which increase the risk of obesity and T2D.
Trokis’ general advice to patients is to lower carbs without cutting them out entirely. “Zero carb” and carnivore-style diets are “not sustainable”, he says. The best diet is low carb “without making life miserable”.
He endorses the science behind Banting, as low carb is known in South Africa, to treat or prevent T2D. Banting promotes animal foods for their nutrient density. However, Trokis believes that in its original version, Banting put “too much emphasis on animal fats”. He promotes plant fats as healthier options.
Given all the conflicting dietary advice, Trokis advises patients to consult a registered dietitian who is up to date with the science supporting low-carb regimens for optimum health.
Chrystal Slater, a registered dietitian and diabetes educator in Cape Town, is one. Like Trokis, Slater favours a low-carb dietary approach. She believes that carbs have been unfairly demonised and attributes the backlash to “a hyperfocus on the nutrient”.
She says that diabetic patients are at the mercy of myths about carbs and that these lead to “defensive eating”. For example, many patients believe that they must eat small amounts of carbs every two hours or have a late-night “bedtime snack” to prevent blood-sugar “crashes”.
“People with diabetes shouldn’t fear carbohydrates,” Slater says. “They need to learn to manage carbs, not eliminate them completely.”
Education is “ultimately more important than restriction”.
She also warns against going too low in carbs as this often leads to patients going “too high in fat”. That’s a trap that can cause unwanted weight gain, she says.
Slater’s dietary mantra is simple: “Diets don’t have to be perfect to be better for health. “Small, sustainable changes, such as swapping sugary cereals for oats or choosing brown rice over white, can add up over time.”
Her advice is premised on a modified Mediterranean diet. Slater recommends “real food” — food that is as close to its natural state as possible. Think lean proteins, whole grains, legumes, vegetables and low-GI fruits (berries get her top vote).
Slater regularly reminds patients to check food labels. “The longer the ingredients list, the less likely a product should find a home in your pantry,” she says.
US research suggests that the order in which people eat carbs, especially for breakfast, can keep blood sugar stable.
A multicentre randomised controlled trial (the “gold standard” of modern science), published in the journal Nutrients, found that a “carbohydrate-last food order” was a “feasible behavioural strategy” for people with prediabetes to prevent full-blown T2D.
Dr Nina Teicholz, US science journalist and nutrition researcher, has some last words.
She says that carbs have not been demonised. They’ve undergone much-needed “correction” from the high-carb diet, heavy in grains, that national dietary guidelines advised us all to eat decades ago.
“Ironically, these guidelines have driven the very diseases (obesity and T2D) that they were meant to combat,” Teicholz says. “Ratcheting back from a high-carbohydrate diet is a much-needed correction to fight chronic diseases.”
Teicholz has an impeccable academic pedigree: a biology degree from Stanford, a master’s in public policy from Yale and a doctorate on evidence-based nutrition policy from the University of Reading in 2024.
She is also the author of the landmark bestseller book The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet (2014). In it, she revealed how poor science, conflicts of interest and politically driven policy distorted nutrition advice over decades.
She showed how unscientific high-carb advice and the equally scientifically dodgy “diet-heart hypothesis” became grand narratives, rallying cries for governments and health authorities that shaped half a century of nutrition dogma.
The hypothesis, first popularised in the mid-20th century by American physiologist Dr Ancel Keys, was seductive in its simplicity: “Fat in the mouth equals fat in the arteries.”
Teicholz showed how the hypothesis launched the “war on fat” under Keys’ watch and pushed populations towards unhealthy vegetable oils and refined carbohydrates.
Yet of the three macronutrients — carbohydrate, protein and fat — only carbohydrate foods are scientifically shown to be “not essential for human life”, Teicholz says.
And while glucose is regularly described as a “preferred fuel”, the body can make the amount of glucose we need from fat and protein, she says.
The US National Academies of Sciences confirmed in 2005 that the essential amount of carbohydrate food required to sustain life is “zero” — provided that “adequate amounts of protein and fat are consumed”.
To that end, Teicholz follows a low-carb diet, getting carbs mostly from green vegetables for fibre. She studiously avoids sugar in any form, including honey and fruit. She reminds us that “sugar in any form is still sugar”.
It makes sense, of course, to heed advice from authoritative sources when health is at stake. However, Albert Einstein warned us that “blind belief in authority is the greatest enemy of truth”.
And Benjamin Franklin sternly reminded us that “every citizen’s first responsibility is to question authority”.
This article was first published in Business Day.
