Since the advent of sweeteners in the 1980s, we have not seen any decrease in obesity or diabetes — quite the contrary. Yet they have been embraced and adopted by the food industry, and today they are even a central pillar of the Nutriscore rating. After understanding what drives us towards the sugar urge, you have probably asked yourself: “What about sweeteners then? A little sweetness without raising blood sugar — that can’t hurt!” But what are the health impacts of sweeteners? And how do you navigate the different types of natural or artificial sweeteners? Let’s take stock.

The different categories of sweeteners

There are different categories of sweeteners. Let’s look at them together in detail.

Sweeteners that raise blood sugar

These sweeteners provide calories.

Traditional sweeteners: simple sugars (table sugar, cane sugar…)

Since “sweetening” is synonymous with adding sweetness, classic sugars — glucose, fructose, sucrose, and other natural sugars — are in reality sweeteners, though this is not part of our collective imagination. We tend to equate sweeteners with: sweet taste + 0 calories. This equation applies to the best-known sweeteners, called “intense”, which have a much higher sweetening power than sucrose (approximately 30 to 500 times more). In this category: saccharin, cyclamates, aspartame, and sucralose. Let’s set stevia (rebaudioside) aside for now (see below).

Table sugar (glycaemic index 65) has a bad reputation because it is refined. We often prefer unrefined cane sugars and their multiple variants (glycaemic index ranging from 55 to 65): muscovado, rapadura, jaggery, kokuto, etc. The word “unrefined” is appealing as it implies more nutrients and fewer refining processes, but we must not forget that these “brown, golden” sugars are made with molasses — the caramelised residue of the sugar refining process: this generates toxic compounds known as Maillard bodies.

It should also be noted that, for cost reasons, some “whole” brown sugars are in reality white sugars “arranged” with artificial flavourings and colourings (caramel = E150). Even if we buy less white sugar today than our grandparents did, our consumption of hidden sugars is vastly higher.

White sugar and cane sugar are two ideal sugars for fermentations such as kefir or kombucha. In these fermented drinks, the sugar is transformed by the micro-organisms, which brings the total content down to 1–2% — entirely acceptable within a healthy diet, with a living product rich in probiotics.

Natural sweeteners (maple syrup, honey, agave syrup, coconut sugar…)

You may wonder whether natural sweeteners are healthier? Indeed, “healthy” natural sugars — such as maple syrup, agave syrup, honey, or coconut flower sugar — are often found in ultra-healthy and trendy recipes on social media. It’s appealing and guilt-free, right? So what to do?

1 – The sweetener to avoid

Agave syrup was put in the spotlight by David Servan-Schreiber because it barely raised blood sugar. This is indeed one of the characteristics of fructose, whose molecular structure differs from that of glucose. Fructose is therefore metabolised in the liver via the same pathway as alcohol (see the work of Dr Lustig) and converts up to 30% into triglycerides. The consequence: hepatic steatosis, an accumulation of fatty acids in the liver — the famous NASH syndrome or non-alcoholic fatty liver disease. Dr Schreiber later revisited this point and withdrew his initial recommendations.

Rest assured, this does not apply to the fructose in fruit, which is present in small quantities (depending on the fruit type) and embedded in fibre with other protective nutrients such as antioxidants. As Professor Lustig would say: “The poison comes with its antidote.” The real danger of fructose is when it is extracted — like the infamous high fructose corn syrup (HFCS) added to (ultra)processed products: track it on labels!

2 – Sweeteners to limit

a) Coconut flower sugar
Next up is coconut flower sugar, which has seen a new wave of Western popularity thanks to its particularly low glycaemic index (GI) of 35. This false data, originally issued by the Polynesian government, has since been revised upward: the GI of coconut sugar has since climbed back to 55, bringing it closer to honey.

b) Honey
Beyond its wonderful medicinal virtues, honey has a GI varying from 50 to 70 depending on its glucose/fructose proportion. Acacia honey has often been spotlighted for its health benefits with a lower GI, but knowing the fate of fructose, should we really be racing for the lowest GI? Honey should not be heated — it is added to warm drinks after they have cooled, just before drinking. Look for authentic raw honey; avoid “fake honeys” diluted with sugar syrups (they don’t crystallise).

c) Maple syrup
Maple syrup is rich in antioxidants and minerals (Zn, Mn). Its glycaemic index is moderate, around 54 — lower than table sugar, making it a better option. Considered healthier in part thanks to its beneficial organic compounds, maple syrup is also produced sustainably, often from ecologically managed forests without chemical use. Maple water is heated and evaporated, simply reduced to syrup.

All these unrefined natural sugars certainly have advantages — they contain more fibre and nutrients. One could deliberate at length on the pros and cons of each. That said, most of them raise blood sugar and “remain sugar”. The ideal is to wean our taste buds off overly sweet tastes and not to oversaturate our neuronal reward circuits, which will always tend to demand more for the same effect.

Bulk sweeteners (polyols: xylitol, erythritol…)

These sweeteners are to be used with discernment.

Bulk sweeteners — polyols — have a limited sweetening power compared to sucrose (0.5 to 1.5 times). The most well-known polyols: sorbitol, xylitol, mannitol. Except for erythritol, which does not raise blood sugar, they have a very slight glycaemic index with the advantage of being non-cariogenic. Xylitol has a GI of 7 and can be gently heated without altering its taste.

The particularity of these sugars is that they are very poorly absorbed by the intestine. They therefore have a “yield” of less than 4 kcal/g attributed to sugars. They are subsequently metabolised by the microbiome — with a priori a rather positive effect on it, but… They are part of FODMAPs (P for polyols) and can therefore cause intestinal disturbances in sensitive individuals and/or in a dose-dependent manner. They should therefore be consumed sparingly (proven laxative effect). Erythritol seems to have the best profile here, but it doesn’t suit everyone as it may promote platelet aggregation (in large quantities — which is not practically the case).

Whether for xylitol or erythritol, we use them in small quantities, especially due to their price (10–15x more expensive than table sugar).

Artificial intense sweeteners (aspartame, acesulfame…)

These synthetic sweeteners do not raise blood sugar and provide no calories. These are sweeteners to discard.

Since the advent of dietetics in the 1970s, these “zero sugar” products have dangled in front of us an ideal health profile — no sugar, no calories. But what are the dangers of artificial sweeteners on health?

Aspartame is qualified as neurotoxic by numerous studies. Their effect on intestinal microbiome — impoverishing the diversity of eubiotic micro-organisms — is well demonstrated.

And what about the deception of sweet taste? Real sugar, in the mouth, already triggers several physiological mechanisms that prepare our organism for the reactions it will face (glucose absorption, blood sugar rise, insulin elevation, glucose passage into the cell, appetite-regulating hormones). All of this is a well-orchestrated composition. But by fooling our system with sweeteners that don’t raise blood sugar, how does our body react? It prepares itself and opens all channels that allow better glucose absorption. Intense sweeteners, while not directly generating an insulin spike, increase the expression of the GLUT-2 transporter on the brush border of enterocytes, facilitating the absorption of glucose present in the digestive lumen.

You may have heard that even the sweet taste alone in the mouth can trigger insulin release? This is partly true for sucralose (brand names Canderel or Splenda) and for certain metabolic profiles: insulin resistance, type 2 diabetes. In these conditions, sucralose elevates GLP1, an incretin that stimulates insulin production — and this from the mouth itself, via alpha-gustducin. Yet sucralose represents 27% of the sweetener market and hides in many industrial products, sodas, alcoholic beverages — and is often recommended to diabetics to avoid blood sugar spikes.

Moreover, these sweeteners do not activate dopaminergic reward circuits, not providing the brain with the expected satisfaction (which risks retaliation!).

With the exception of stevia, all intense sweeteners are harmful:

• Microbiome impoverishment leading to dysbiosis, potentially feeding candidiasis, reflux, or low-grade inflammation
• No cerebral reward, with risk of dissatisfaction and compensation
• No hypothalamic activation (para/orthosympathetic) which thus does not induce the metabolic mechanisms linked to sugar consumption, essential for maintaining homeostasis
• Uncertainty about accumulation of authorised ADIs to reach the toxic threshold
• Evident links with the genesis of tumours in mice, established in recent studies
• Neurotoxicity of aspartame, which has been well demonstrated

Natural intense sweeteners of plant origin (stevia, monk fruit, yacon syrup…)

I recommend using these in moderation.

Stevia
Unlike other intense sweeteners, stevia is of natural, plant origin — extracted from the leaves of Stevia rebaudiana. This sweetener has been part of Japanese habits for at least 40 years, following the withdrawal of aspartame from that market. Several recent studies have demonstrated its safety, showing a good profile. According to B. Arumugam (Stevia, as a Natural Sweetener: A Review), it even reveals certain positive side effects: “The active compounds isolated from Stevia rebaudiana possess interesting medicinal activities, including antidiabetic, antihypertensive, anti-inflammatory, antioxidant, anticancer, and antidiarrhoeal activity.”

But stevia has a slightly metallic and liquorice taste that some people dislike — despite its gustatory aspect having greatly improved since it was first commercialised. It also cannot be heated, which limits its use in cooking.

Monk Fruit (Allulose)
We can also mention Monk Fruit, or Allulose, which would have similar properties to stevia with a neutral taste. It is increasingly easy to find in European grocery stores. It can be heated and does not cause intestinal disturbances like polyols do. We may still lack long-term perspective, but this sweetener currently takes the top spot on the podium.

Yacon syrup
Another very interesting exotic natural sweetener is yacon syrup. Yacon, or earth pear, is a tuber with a sweet taste and a pear-like consistency, resembling a chayote. Composed of inulin and fructo-oligosaccharides, it is heated to obtain a syrup. Its advantages:

• With a glycaemic index of 1, it does not raise blood sugar
• Trophic effect on the microbiome (inulin and FOS are prebiotics) — though it is part of FODMAPs
• Its richness in fibre regulates blood sugar and improves insulin sensitivity

It therefore has an excellent profile as a healthy natural sugar.

My 4 tips to sweeten your dishes without sugar or sweeteners

Cinnamon
Cinnamon, a wonderful blood-sugar-lowering spice, can be sprinkled on your dishes, tagines, smoothies, fruits, granolas; added to herbal teas, etc.

Vanilla
Vanilla, in powder or extract form, also gives a sweet effect — it allows you to greatly reduce sugar additions in the making of healthy pastries, creams, and nut butters.

Liquorice powder
If you have no contraindication, liquorice powder pairs well with both sweet and savoury dishes — if you like its taste.

Orange or lemon peel / peel powder
These can add a very pleasant citrus note to fruit salads, leaf salads, herbal teas, and chocolate mousse.

Health impacts of sweeteners: key takeaways

The consumption of sugars must therefore be placed in a global context, with a view of the whole meal. Because it is here that the assessment of glycaemic load matters: pairing your sugars with fibre, proteins, good fats, and acid (lemon juice, vinegar, sourdough) will lower the total glycaemic load.

The key message: no sugars on an empty stomach!

As for the rest, “added” sweeteners should be considered as aids to weaning off sugar, not as a panacea. Is the quest for the latest sweet-substitute innovation not in vain, if we return to basics: we eat too much sugar. A 6-year-old child today has consumed as much sugar as their grandparents did in an entire lifetime!

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Clara Materne