How Harmful Is Sugar Really? And Should You Be Worried About Adding It to Your Child’s Food?

Apparently, the controversial ingredient in my cannellini bean blondies isn’t the beans.

It’s the sugar.

The recipe contains cannellini beans, wholemeal flour, vegan yoghurt… and one cup of brown sugar spread across the whole batch.

And whenever I share recipes like this, I can almost guarantee someone will say:

“But that’s a lot of sugar.”

I get it.

Especially if you came to plant-based eating because you wanted your family to be healthier.

You start reading about whole-food plant-based diets. You discover people talking about reversing chronic disease. You hear that processed food is bad, oil is bad, salt is bad and sugar is definitely bad.

Suddenly a cup of brown sugar sitting in a mixing bowl doesn’t look like an ingredient.

It looks like a health emergency.

And I think we need to talk about that.

Because while there are very good reasons not to build a child’s diet around soft drink, lollies and sugary foods, the research on sugar is considerably more nuanced than “sugar is toxic.”

And when we lose that nuance, feeding children — particularly fussy children — can become much harder than it needs to be.

First: I actually like NutritionFacts

I want to make this really clear because this isn’t a Dr Greger takedown.

I think NutritionFacts.org has done an incredible job of making nutrition research accessible, and I have enormous respect for the work Dr Michael Greger has done.

And.

Health information can still land very differently when you’re a parent trying to feed actual children.

I know because it has happened to me.

I’ve read books about the “optimal” diet and immediately thought:

Oh my goodness. We need to eat better.

I’ve cleared things out of the fridge. Bought all the ingredients. Planned the fabulously healthy recipes.

And then discovered that making those recipes every day while parenting was… slightly less straightforward than the book made it sound.

And getting my children to actually eat them?

Even less straightforward.

Ironically, once I stopped trying to make our diet perfect, my kids started eating a much wider range of foods.

More beans.

More wholegrains.

More fruit and vegetables.

Not because I lowered my standards.

Because I started looking at nutrition through the lens of how children actually learn to eat.

That distinction matters.

How scary nutrition messages get translated

NutritionFacts has written:

“A growing body of scientific evidence suggests that the fructose added to foods and beverages in the form of table sugar and high fructose corn syrup in large enough amounts can trigger processes that lead to liver toxicity and other chronic diseases.”

Notice an important part of that sentence:

“In large enough amounts.”

The statement itself is considerably more cautious than sugar is toxic.

But I also know exactly how a worried parent can read it.

Fructose → liver toxicity.

Table sugar contains fructose.

My recipe contains table sugar.

Therefore I’m damaging my child’s liver.

And that is where we need to look more closely at what the research actually studied.

Because dose matters.

Food source matters.

Energy intake matters.

And drinking a large quantity of sugar in a soft drink is not automatically equivalent to eating some sugar as part of a mixed meal or homemade food.

Yes, high sugar intake is associated with poorer health

I’m not going to swing to the other extreme and tell you sugar is a health food.

It isn’t.

A major 2023 BMJ umbrella review looked at 73 meta-analyses covering 83 different health outcomes.

It found 45 statistically significant harmful associations with sugar consumption.

So yes — there are legitimate health reasons to avoid very high sugar intakes.

But here’s the bit that tends not to fit nicely into an Instagram graphic.

Of those 83 outcomes:

• 74 came from observational evidence
• only nine came from randomised controlled trials
• the observational evidence was rated low or very low quality
• none of the outcomes had high-quality evidence

And perhaps most importantly:

58 of the 83 sugar exposures involved sugar-sweetened beverages.

That’s about 70%.

Soft drink is doing an awful lot of heavy lifting in the “sugar research”.

Which matters when the question you’re actually asking is:

“Should I put some sugar in my child’s bean muffin?”

Sugary drinks aren’t the same research question as sugar in food

Think about the difference.

You can drink several hundred calories of soft drink extremely quickly.

It doesn’t contain beans.

Or wholemeal flour.

Or protein.

Or much fibre.

It is very easy to consume without it having the same effect on fullness as a solid meal.

Now compare that with a blondie made from beans, wholemeal flour and yoghurt that happens to have sugar added to make it taste good.

That doesn’t magically turn the added sugar into “fruit sugar”.

Added sugar is still added sugar.

But our bodies eat foods and meals — not isolated nutrients floating around by themselves.

Fibre, protein, fat, physical structure, portion size and the rest of the meal can all affect digestion, satiety and how much energy we consume.

So we shouldn’t assume that every source of sugar has identical health effects.

And increasingly, the research doesn’t support that assumption either.

What about diabetes?

This is a perfect example.

A 2025 systematic review looked separately at sugar-sweetened beverages, total sugar, sucrose, added sugar and fructose.

Sugar-sweetened beverages were associated with a higher risk of type 2 diabetes.

But when researchers looked specifically at added sugar, every additional 20g per day was associated with essentially no change in risk:

RR 0.99, 95% CI 0.96–1.01.

Fructose itself wasn’t significantly associated with diabetes risk either.

Does that mean unlimited sugar prevents diabetes?

Obviously not.

It means “sugar causes diabetes” is an inadequate explanation of a much more complicated relationship.

The source matters.

The amount matters.

The dietary pattern matters.

But doesn’t fructose cause fatty liver?

At sufficiently high intakes — particularly when it’s providing significant additional energy — fructose-containing sugars absolutely can contribute to liver fat.

But again: look at the exposure.

Some controlled studies have given people very high fructose intakes — around 104–220g of fructose every day, supplying an additional 21–35% of their energy requirements.

Under those conditions, liver fat and liver enzymes increased.

When fructose replaced other carbohydrates calorie-for-calorie without supplying excess energy, those effects largely disappeared.

A later meta-analysis of 51 controlled trials involving 2,059 people found a similar pattern.

When fructose-containing sugars were added as excess energy, liver fat increased.

When they replaced other nutrients calorie-for-calorie, researchers did not find the same increase.

And sugar-sweetened beverages appeared to be a particularly important source when excess calories were being consumed.

That’s quite different from saying:

“The teaspoon of sugar in your child’s food is toxic to their liver.”

It isn’t what the research shows.

And no — “sugar feeds cancer” is still far too simplistic

This is probably one of the scariest claims people hear about sugar.

And there is a little piece of biology sitting underneath it.

Cancer cells use glucose.

But so do normal cells.

And even if you removed table sugar from your diet completely, your body would still maintain blood glucose — including by making glucose itself through a process called gluconeogenesis.

So:

Cancer cells use glucose

does not automatically mean:

Eating sugar feeds cancer.

And when we look at the actual research on sugar intake and cancer, the picture is much less dramatic than that slogan suggests.

A 2023 meta-analysis of prospective cohort studies looking at cancer mortality found essentially no association for:

• total sugar
• fructose
• added sugar
• sucrose

An earlier systematic review looking at cancer incidence found that most studies examining total sugar, sucrose and fructose were also null.

Some individual studies did report associations for particular sugar exposures or particular cancers — so this isn’t me saying the evidence is universally zero.

But overall, the evidence has been inconsistent and limited, rather than showing a clear pattern that eating table sugar directly causes cancer.

There are studies that raise concerns about sugary drinks.

For example, the French NutriNet-Santé study followed around 101,000 adults and found that each additional 100mL per day of sugary drinks was associated with about an 18% higher incidence of overall cancer.

That sounds alarming.

But again — context.

It was an observational study, so it can’t prove that the drinks caused those cancers. Residual confounding is possible. And interestingly, 100% fruit juice was also associated with increased cancer risk in that study.

Which makes it very difficult to turn that finding into:

“Table sugar causes cancer.”

The more plausible concern at a population level is that high intakes of sugary, energy-dense foods and drinks can contribute to excess energy intake and weight gain — and excess body fat is itself associated with increased risk of several cancers.

That’s quite different from:

Sugar molecule → cancer cell grows.

Again.

Nuance.

Annoying for social media.

Quite useful when you’re deciding whether a tablespoon of sugar belongs in your child’s muffin.

There is one place where sugar deserves particular respect: teeth

Dental health is different.

Free sugar contributes directly to dental caries, and the evidence here is much clearer.

Frequency matters too — constantly exposing teeth to sugary foods and drinks throughout the day is not the same as having something sweet as part of a meal.

The World Health Organization’s recommendations to reduce free sugar intake are strongly informed by the evidence around both dental caries and body weight.

So no, my message isn’t:

“Sugar doesn’t matter. Chuck it in everything.”

It’s:

Sugar has health considerations. But that doesn’t make every use of sugar dangerous.

Those are two very different statements.

But what about recommendations to avoid added sugar in babies and toddlers?

This is important — because nutrition guidelines around the world are very cautious about added sugar in the first years of life.

The exact recommendations vary by country.

In the US, guidance explicitly recommends avoiding added sugars before the age of two.

Australian guidance recommends not adding sugar to infant foods, avoiding sugar-sweetened drinks and limiting foods with added sugars.

Canadian guidance recommends preparing foods for young children with little or no added sugar.

And UK and international guidance similarly encourage keeping added or free sugars very low in babies and young children.

So yes.

If your baby or toddler is happily eating a varied, nutritionally adequate diet without added sugar, that’s a great thing to aim for.

There is no nutritional need to start adding sugar just for the sake of it.

Babies and toddlers have high nutrient requirements but relatively small stomachs, so ideally most of the food they eat will provide useful amounts of things like iron, protein, fats, vitamins and minerals.

Dental health matters too.

And sugar-sweetened drinks are particularly worth avoiding.

But I think we need to be careful about what happens when:

“Try to minimise added sugar in babies and toddlers”

quietly becomes:

“Any added sugar before two is dangerous.”

Those aren’t the same statement.

And that’s particularly important for parents feeding children whose diets are already becoming restricted.

If your toddler happily eats beans, wholegrains, tofu, vegetables and all the other foods they need without added sugar?

Brilliant.

Keep doing exactly that.

But if your child is refusing more and more foods, the question sometimes changes.

It may no longer be:

“Could I make this exact food without sugar?”

It may be:

“Will my child eat this food at all without it?”

That’s where I don’t want a population-level recommendation to become another source of panic or perfectionism.

Because an occasional food containing some added sugar is not the same thing as a diet dominated by sugary foods and drinks.

And the evidence we’ve looked at in this article does not suggest that a small amount of added sugar in an otherwise nutritious food suddenly makes that food dangerous.

The guidelines are a useful goal. They don’t need to become a test of whether you’ve fed your child perfectly.

Because nutrition guidance should help us feed children well.

It shouldn’t make us so frightened of individual ingredients that feeding them becomes harder.

Which brings me back to those bean blondies

Imagine I offer a child this:

Wholemeal flour + beans + vegan yoghurt.

They refuse it.

I remove the plate.

Nutritionally immaculate.

Zero beans consumed.

Now imagine I offer:

Wholemeal flour + beans + vegan yoghurt + enough sugar to make the recipe genuinely enjoyable.

And they eat it.

Suddenly they’ve eaten beans.

They’ve eaten wholegrains.

They’ve eaten protein and fibre.

They’ve eaten energy — which, incidentally, growing children require quite a lot of.

Is that automatically a worse nutritional outcome simply because the second version contains added sugar?

I don’t think that’s a sensible way to assess a child’s diet.

And importantly, a cup of sugar in a mixing bowl isn’t a cup of sugar going into your child.

It’s divided across the entire recipe.

Dose matters.

Frequency matters.

And the rest of their diet matters.

The pursuit of the “perfect” diet can make a child’s diet worse

This is the part I care about most.

When parents become frightened of sugar, oil, salt, processed foods, sauces and anything else that isn’t considered perfectly whole-food plant-based, the list of foods they’re willing to offer can get smaller and smaller.

Meanwhile, they’re raising a child whose accepted-food list might already be tiny.

Those two things don’t always play nicely together.

For a fussy eater, I am far more interested in helping them build a varied, nutritionally adequate diet than achieving ingredient-list perfection.

Because sometimes ketchup helps a child eat tofu.

Sometimes breadcrumbs help them approach a vegetable.

Sometimes chocolate gets nuts and seeds into a snack.

And sometimes sugar makes a bean blondie taste like something a child actually wants to eat.

That’s not failing at healthy eating.

That’s feeding a child.

So… how worried should you be about sugar?

I wouldn’t recommend a child’s diet be dominated by sugary drinks, sweets and high-sugar foods.

I would pay attention to dental health.

I would still aim for plenty of fruit, vegetables, legumes, wholegrains, nuts and seeds.

And I would absolutely keep sugar intake in perspective.

Because the research supports reducing high intakes of free sugar — particularly sugar-sweetened beverages.

It does not support treating every teaspoon of sugar added to a child’s food as though you’re sprinkling chronic disease into their lunchbox.

And if a little sugar helps your child move from:

“Absolutely not.”

to

“Actually… can I have another one?”

while eating beans, wholegrains or another food they’ve previously rejected?

That deserves to be evaluated in the context of their whole diet.

Not against an imaginary perfect one.

Because with kids — especially fussy kids — sometimes the healthiest diet isn’t the diet that looks perfect on paper.

It’s the nutritious one they can actually eat.

Next up: if you use sweetness to help a child accept a new food, will they always need it sweet? I’ll look at what the research on repeated exposure, flavour learning and children’s sweet preferences actually tells us.

Sources

Huang Y, et al. Dietary sugar consumption and health: umbrella review. BMJ. 2023.

Dietary Sugar Intake and Incident Type 2 Diabetes Risk: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. Advances in Nutrition. 2025.

Important Food Sources of Fructose-Containing Sugars and Non-Alcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis of Controlled Trials. Nutrients. 2022.

Important food sources of fructose-containing sugars and adiposity: A systematic review and meta-analysis of controlled feeding trials. American Journal of Clinical Nutrition. 2023.

Huang C, Liang Z, Ma J, Hu D, Yao F, Qin P. Total sugar, added sugar, fructose, and sucrose intake and all-cause, cardiovascular, and cancer mortality: A systematic review and dose-response meta-analysis of prospective cohort studies. Nutrition. 2023;111:112032. doi:10.1016/j.nut.2023.112032.

Makarem N, Bandera EV, Nicholson JM, Parekh N. Consumption of Sugars, Sugary Foods, and Sugary Beverages in Relation to Cancer Risk: A Systematic Review of Longitudinal Studies. Annual Review of Nutrition. 2018;38:17–39. doi:10.1146/annurev-nutr-082117-051805.

Chazelas E, Srour B, Desmetz E, et al. Sugary drink consumption and risk of cancer: results from NutriNet-Santé prospective cohort. BMJ. 2019;366:l2408. doi:10.1136/bmj.l2408.

World Health Organization. Guideline: Sugars intake for adults and children.