When I first heard someone describe sugar as toxic, I rolled my eyes. Everything seems to be bad for us these days. I put a little sugar in my coffee, enjoyed the occasional cronut, and exercised hard enough to feel I had earned my treats. How bad could it really be?
Then I started looking at the food I actually ate, rather than the diet I imagined I had. I read supermarket labels, met food developers, talked to doctors, and visited hospital wards where the consequences of poor health were impossible to shrug off.
The most uncomfortable discovery was personal. I looked reasonably fit. I thought I ate sensibly. My blood results told a less reassuring story.
This is not simply a contest to find the one ingredient responsible for every health problem. Portion sizes, processed foods, inactivity, and family history all matter. But sugar deserves much closer attention than I had been giving it.
Is Sugar Toxic, or Is That Just a Scary Headline?
Professor Robert Lustig does not mince his words. His argument is that excessive sugar consumption can promote fat accumulation in the liver and interfere with the systems that regulate appetite. He believes the food industry has made the problem worse by putting sugar into an extraordinary range of processed products.
He even compares the evidence against sugar with the evidence against tobacco. That is a striking claim, and I challenged him on it. It is also his position, not a comparison everyone in the debate accepts.
The industry representative I later spoke to argued that calling sugar a poison exaggerates its role and strips away the context of quantity and overall diet.
Interestingly, quantity is central to Lustig’s explanation too. He describes a limited capacity to process sugar: a little is one thing, repeatedly overwhelming that capacity is another.
There is no nutritional requirement to add table sugar to your diet. That does not mean the body does not use glucose, or that every food containing naturally occurring sugar belongs in the bin. It means the spoonfuls we add, and the sugars manufacturers add for us, are not something we need to seek out.
The Sugar I Was Not Counting
A supermarket is an excellent place to have your assumptions dismantled.
I expected chocolate spread to contain plenty of sugar. What surprised me was finding it in foods I thought of as savoury: Marmite, tomato sauce, light mayonnaise, flavoured tuna, and baked beans.
In the particular products I checked, the amounts translated into roughly:
- Chocolate spread: two teaspoons of sugar per serving.
- Tomato sauce: just over one teaspoon per serving.
- Light mayonnaise: about one and a half teaspoons per serving.
- Baked beans: nearly four teaspoons per serving.
Those figures describe the products on those shelves, not every version sold today. They also require attention to serving size. The seven teaspoons I calculated for a small Marmite pot represented the whole pot, not a single spread on toast.
That distinction matters. Comparing a whole container with someone else’s serving can make a label sound more alarming than it is. Equally, a modest-looking serving figure can conceal how much we actually use.
The sugar was not necessarily secret. It was sitting on the labels. I simply had not thought to look.
Fruit juice caught me out as well. I knew fizzy drinks were sugary, but juice occupied a much healthier category in my head. The World Health Organization’s guidance on sugar intake is a useful reference because it distinguishes free sugars, including those in juice, from sugars within intact fruit.
Why Manufacturers Put Sugar in Savoury Food
Once you notice sugar across the supermarket, the obvious question is why it is there.
A food technologist gave me an answer that was rather less mysterious than I expected: sugar is cheap.
Consider an oil-based dressing. Oil costs money. A manufacturer can remove some of that more expensive ingredient and increase the sugar while working toward a price customers will accept.
The final recipe also depends on taste testing. In a small company, that might involve the marketing manager and office staff. A larger business may commission sensory panels with consumers.
None of that automatically proves sinister intent. Businesses make products people will buy. But it does reveal the priorities shaping our food: cost, taste, price points, and sales. Nutritional quality is not necessarily the deciding factor.
The same tension appears in the low-fat story. I had absorbed the wonderfully simple idea that eating less fat meant being less fat. Lustig argues that manufacturers often replaced lost flavour in low-fat products with sugar.
A low-fat label is not a complete health assessment. My light mayonnaise was a fairly pointed reminder of that. The useful response is not to declare all fat good and all carbohydrate bad. It is to stop letting one reassuring phrase do all our thinking.
Looking Healthy Is Not the Same as Being Healthy
My breakfast seemed respectable enough: coffee with one sugar, low-fat milk, and muesli. I also took exercise seriously, sometimes hauling a pack loaded with books and rocks up a hill. As fitness plans go, it was not particularly glamorous, but it was certainly strenuous.
My reasoning was simple. Calories in, calories out. Work hard, enjoy something sweet.
Angela, a young Auckland professional I met, had a different routine. She relied heavily on takeaways and kept sweets at her desk and within reach of her bed. She looked slim, but her food habits worried the registered nutritionist she consulted.
Angela described herself as addicted to sugar. Later, a woman living with serious diabetes complications described the same feeling of needing sweets. Those experiences show how powerful a habit can become, although an individual account does not settle the scientific question of addiction.
Then came my own reality check. After keeping a food diary and having blood tests, I learned that my triglycerides were 2.4 mmol/L, above the 1.7 mmol/L target used in my consultation.
Triglycerides are fats in the blood. My nutritionist was concerned about my diet and cardiovascular risk. A result like that is not, by itself, proof that sugar caused the problem. But it was enough to puncture my confidence.
At 46, I had expected reassurance. Instead, I had something to change.
Diabetes Has a Cost Beyond the Diagnosis
At Middlemore Hospital in South Auckland, the debate stopped being abstract.
The dialysis service was caring for hundreds of people whose blood needed to be filtered by machines. The doctor I spoke to estimated dialysis costs at approximately NZ$50,000 to NZ$100,000 per person each year at the time, before counting other treatment or the disruption to working life.
Diabetes complications can affect the kidneys, eyes, nerves, heart, and blood supply to the feet. One patient had lost his big toe following infection. He also had problems involving his eyes, kidneys, and nerves.
Marilyn, 53, had lived with diabetes for 20 years. She described eye complications, a coronary stent, and dialysis three days a week, four hours each visit.
She also spoke candidly about her earlier diet: large quantities of doughnuts, chocolate, lollies, and heavily sweetened tea. Her regret was painful to hear.
These stories are not controlled experiments, and diabetes cannot fairly be reduced to a person’s fondness for sweets. Family history and other factors matter. But they make the stakes of prevention very clear.
The clinician’s most straightforward advice was also the least complicated: reduce sugary beverages, which contribute sugar without offering the nutritional value of a meal.
Children’s Teeth Reveal a More Immediate Harm
Some health consequences take years to emerge. Severe dental decay can become a problem much earlier.
At Nelson Hospital, dentist Dr. Rob Beaglehole showed me the damage being treated in young children. One little girl needed six teeth removed under general anaesthetic. Another child had just turned two and had extensive destruction of the front teeth.
The team described diets high in sugary drinks, including a parent’s account of cola being put into a baby bottle.
The consequences extended beyond a painful tooth. Losing several teeth could affect eating, appearance, social confidence, and later orthodontic treatment. Each operation also occupied a theatre and a team of highly trained staff.
Then we calculated the sugar in some drink bottles. Using approximately four grams per teaspoon, the examples contained:
- A 1.5-litre cola: about 40 teaspoons.
- A 1.5-litre green soft drink: about 47 teaspoons.
- A 600-millilitre cola: about 16 teaspoons.
Those were product-specific calculations, but the quantities were startling. A smaller bottle could still deliver a substantial amount of sugar in one go.
You do not have to agree with every dramatic claim about sugar to see the problem here. Preventing this kind of dental harm is reason enough to rethink what children routinely drink.
What Happened When I Changed My Diet
I followed my nutritionist’s advice, cut back on sugar, and reduced refined carbohydrates. Two months later, my triglycerides had fallen from 2.4 to 1.5 mmol/L.
I also lost weight and went down a belt size. The improvement was encouraging, particularly after assuming there was nothing much wrong in the first place.
Still, my experience needs to remain exactly that: my experience. Several parts of my diet changed together. It does not tell us how much of the improvement came from any single change, or guarantee the same result for someone else.
Maryanne and her husband Gary offered another hopeful example. After diabetes had devastated her family, being told she was prediabetic frightened her into action.
Together, they checked the pantry and fridge, reduced high-sugar products, and began preparing more food themselves. Their version of “sugar-free” was not literally zero sugar. They used label thresholds to keep amounts low and chose a curry paste containing less than one gram of sugar per 100 grams.
They also mentioned using glucose or dextrose as a substitute. Those are still sugars, so swapping names is not the same as eliminating sugar.
Maryanne reported substantial weight loss and no longer being classified as prediabetic. That is encouraging, not a promise that future diabetes risk has vanished. What stayed with me was how much they still enjoyed eating. Less sugar did not mean a joyless kitchen.
Personal Responsibility, Marketing, and the Sugar Tax Debate
The food industry’s response centred on personal responsibility. The representative I interviewed argued that obesity reflects eating too much and moving too little, rather than sugar alone. She also opposed a sugar tax, warning about higher costs for people least able to afford them.
There is a legitimate concern there. Household budgets matter. So does individual choice.
But choices do not happen in a vacuum. Price, convenience, availability, habit, and marketing all influence what ends up in a trolley. I bought three 1.5-litre soft drink bottles for NZ$6. That was quite a lot of persuasion for very little money.
A clinician pointed out that soft drinks could cost less per litre than bottled water. Researchers cited in the investigation modelled a 20% sugary-drink tax that could save lives and raise money for health programmes. That was a projected outcome, not an observed result of a New Zealand tax.
The disagreement is partly about where responsibility belongs. Industry stresses the consumer’s final decision. Lustig argues that government must lead changes across the food supply.
For more context on the commercial side of this debate, The Sugar Lobby explores how the industry responds to concerns about sugar.
A School That Changed the Everyday Choices
At Yendarra School in South Auckland, they were not waiting for everyone else to agree.
The school banned soft drinks and worked to change an entrenched culture of takeaways and junk food. Water, fruit, vegetables, and other everyday lunch foods became part of a different routine.
The principal described changes reaching beyond the school gate. Children began explaining healthier choices to their parents at the supermarket. Staff also reported improvements in children’s weight and classroom behaviour.
Those observations are not the same as a formal evaluation. Nevertheless, the approach offered a practical lesson about behaviour change.
Leadership, clear expectations, repetition, and follow-up helped make healthier choices normal. The school did not simply tell families to take responsibility and leave them to it. It created support around the behaviour it wanted to encourage.
Less Sugar, Without Turning Food Into the Enemy
I began convinced that moderation and exercise had me covered. The trouble was that I had not actually counted how much sugar my version of moderation included.
The clearest starting points are manageable:
- Read the labels on foods you buy routinely, including savoury products.
- Check serving sizes against the amount you actually consume.
- Make water the ordinary choice instead of sugary drinks.
- Seek professional advice about concerning results rather than relying on appearance.
Sugar is not the only contributor to poor health. But acknowledging complexity is not an excuse to do nothing about an obvious, changeable part of the problem.
My diet changed. My blood results improved. And the people I met gave me reasons to care that went well beyond my own belt size.
We do not need to make food frightening. We do need to stop treating large amounts of sugar as an unremarkable feature of everyday life.