Sugar Cravings: What Your Microbiota Is Trying to Tell You

We need to start by saying what sugar cravings are not. Most of the time, they are not a signal of hunger. Nor are they, in themselves, a character flaw. They are a precise neurochemical event that brings together three players that have long been studied separately and are now understood as part of the same circuit: the brain, the gut, and the gut microbiota.

Biologically, sugar is a positive signal. For hundreds of thousands of years, its sources were scarce, ripe fruits available only during short seasons, honey that was difficult to access, and they were always associated with a valuable source of energy. Evolution therefore wired a simple mechanism: when we consume sugar, the brain releases dopamine, the key neurotransmitter of the reward circuit. This circuit, which notably involves the ventral tegmental area and the nucleus accumbens, signals to the body: "Let's do that again." The problem begins when this mechanism, designed for rare foods, encounters an environment where sugar is everywhere, twenty-four hours a day. The reward becomes constant, the signal dulls, the need increases, following a classic pattern of tolerance comparable, in broad terms, to the mechanisms involved in other consumption-related behaviors.

What research has uncovered over the past twenty years is that this brain circuit does not operate in isolation. It is in constant communication with the gut through the vagus nerve, digestive hormones such as ghrelin, leptin, GLP-1 and peptide YY, and metabolites produced by the bacteria themselves. Inserm defines the gut microbiota as "an organ in its own right", whose functions extend far beyond digestion: modulation of the immune system, production of neurotransmitters, regulation of inflammation, and direct influence on eating behaviors². For example, ninety percent of the body's serotonin is produced in the gut, and several key neurotransmitters involved in appetite regulation originate there or derive from precursors produced there.

This is where things become fascinating.

A recent review published in 2025 synthesized the current state of knowledge on the links between the gut microbiota and the dopaminergic system. Its conclusions were striking: some bacteria in the colon directly produce dopamine precursors, others consume them, and the short-chain fatty acids they release through the fermentation of dietary fibers cross the blood-brain barrier and modulate the activity of dopaminergic neurons³.

In other words, the composition of your microbiota influences, without you even realizing it, how sensitive your brain is to reward.

Another recent review focused more specifically on the dopamine D2 receptor, a key regulator of eating behaviors, and showed that the microbiota finely modulates both its expression and sensitivity⁴.

Viewed through the lens of this research, sugar cravings are not merely a psychological impulse. They are also a biochemical message traveling from the gut to the brain.

The idea that microorganisms can shape the behavior of their host is not new in evolutionary biology. Think of the fungus Ophiocordyceps, which alters the behavior of ants to ensure its own reproduction.

Applying this principle to our own eating habits, however, is a more recent concept, and its implications are as unsettling as they are enlightening.

In 2014, three American researchers, Joe Alcock, Carlo Maley, and Athena Aktipis, published a landmark paper in the journal BioEssays. Their thesis was that microorganisms living in the digestive tract are under evolutionary pressure to manipulate their host's eating behavior in ways that promote their own fitness, sometimes at the expense of ours¹.

They proposed two possible mechanisms.

The first is to generate cravings for foods they preferentially feed on, or for foods that suppress their microbial competitors.

The second is to induce a state of discomfort, a form of "dysphoria", until the host consumes the favorable food.

In both cases, what we perceive as a personal craving could, at least in part, be a signal negotiated between our bacteria.

This theory has since given rise to an extensive body of literature, and researchers are beginning to identify concrete situations in which it applies. Bacteria that thrive on simple sugars, certain strains of Candida, or bacteria specialized in the rapid fermentation of carbohydrates, have every interest in encouraging their host to consume sugar regularly.

Conversely, bacteria that feed on complex fibers thrive in more varied diets rich in unprocessed plant foods.

How, in practical terms, does the microbiota send its signals? Several pathways have now been documented.

Short-chain fatty acids (SCFAs), namely butyrate, propionate, and acetate, produced through the fermentation of dietary fibers by beneficial bacteria in the colon, cross the intestinal barrier, travel to the brain, and stimulate the release of GLP-1 and peptide YY, two powerful satiety hormones.

When these SCFAs are lacking, typically in people who consume too little fiber, satiety signals weaken and cravings gain ground. Conversely, certain gas-producing and inflammation-triggering bacteria alter hormonal signals in a way that promotes persistent cravings.

As part of the French Gut project, INRAE is specifically exploring these microbial signatures associated with healthy or unbalanced dietary patterns⁵.

Clinical observations align with the theory. People whose microbiota has become less diverse, a condition known as dysbiosis, more frequently report sugar cravings, impaired satiety, and greater sensitivity to ultra-processed foods.

And the mechanism reinforces itself: the more sugar we eat, the more we favor the strains that crave it; the more bacterial diversity declines; the more satiety signals collapse.

Sugar feeds what asks for sugar.

Breaking this cycle is not simply a matter of willpower. It is a matter of reshaping the terrain.

The microbiota never acts in isolation. Several factors can either amplify or dampen its signals. Ignoring them is like focusing on the last piece of the puzzle while forgetting all the others.

Chronic stress is probably the greatest driver of sugar cravings in the modern world. Under the influence of cortisol, a hormone released during prolonged stress, the body becomes more sensitive to highly palatable, calorie-dense foods: sugar, fat, or a combination of both.

Landmark studies have shown that, under stress, women consume significantly more "comfort foods" than those in a control group, and that this preference persists for hours after the triggering event⁹.

The mechanism is probably adaptive. In the face of danger, the body seeks quick fuel. But it is poorly suited to the chronic stress of office work, screens, and constant notifications.

A short night can alter appetite hormones within just a few hours. Ghrelin, the hormone that stimulates hunger, increases. Leptin, the hormone that signals fullness, decreases.

The result is a stronger feeling of hunger the next day, a greater attraction to energy-dense foods, and a prefrontal cortex, the part of the brain responsible for decision-making and inhibition, that is less effective at resisting temptation.

That is why, on a Monday morning after a poor night's sleep, we struggle to resist the pastries at breakfast.

No amount of willpower can compensate for insufficient sleep.

For a long time now, sugar has not been limited to the spoonful we add to our coffee. According to ANSES recommendations, the average intake of added sugars in the French adult population far exceeds the recommended threshold⁶.

Most of it comes from products we do not suspect: sauces, industrial breads, ready meals, sweetened plant-based drinks, "healthy" yogurts, and breakfast cereals.

This invisible consumption maintains chronically elevated blood sugar levels and reinforces dopaminergic sensitivity to sweet tastes. In other words, it keeps cravings alive.

The paradox is well known: the more strictly we forbid ourselves from eating sugar, the more we crave it. Restriction creates salience. The forbidden food becomes more present in our minds, and the slightest lapse often triggers overindulgence.

Current dietary recommendations, particularly those promoted by Santé publique France through the Manger Bouger program, emphasize long-term balance rather than strict avoidance: limit added sugars, prioritize fruits and whole grains, and diversify energy sources⁷.

The goal is not zero sugar. It is a peaceful relationship with food.

Breaking free from the cycle of sugar cravings requires acting simultaneously on the underlying terrain, the microbiota, blood sugar regulation, and sleep, as well as on the triggers: stress, environment, and habits.

The most powerful levers are not the ones we usually imagine.

According to the scientific literature, this is the most foundational lever. Three elements work in synergy.

Prebiotic fibers, such as cooked vegetables, fruits with their skin, legumes, and oats, nourish the bacteria that produce SCFAs, those well-known short-chain fatty acids that reactivate satiety signals.

Polyphenols, found in berries, green tea, raw cocoa, and herbs, selectively promote the growth of protective strains such as Akkermansia muciniphila, whose decline has been associated with metabolic dysregulation.

Live ferments, including traditional yogurt, kefir, kombucha, raw sauerkraut, and probiotic shots, directly introduce new strains into the ecosystem.

Allow four to twelve weeks of regular intake before expecting a stable effect on cravings.

A breakfast high in fast-digesting sugars, such as pastries, fruit juice, or sugary cereals, causes a spike in blood sugar levels followed by a crash a few hours later.

It is this crash that triggers the mid-morning craving, regardless of any emotional factors.

Replacing it with a breakfast rich in protein, fiber, and healthy fats, such as eggs and avocado, oats and nuts, or Greek yogurt with berries, changes the blood sugar curve throughout the morning and prevents a large proportion of cravings before they even begin.

Seven to nine hours of sleep per night are not a luxury. They are the most powerful hormonal lever for stabilizing appetite. A regular bedtime, limiting screen exposure in the evening, and keeping the bedroom cool and dark are simple recommendations, but their cumulative effect is considerable.

When it comes to stress, effective approaches are not mysterious either: five minutes of heart rate coherence twice a day, walking outdoors, regular physical activity, even at a moderate intensity, and contemplative practices such as meditation or yoga. The goal is not to never feel stressed again. It is to recover more quickly and, in doing so, avoid fueling cravings.

Many people believe they can work around the problem by replacing sugar with sweeteners such as aspartame, sucralose, or industrially processed stevia.

A 2025 review synthesized the available evidence on the impact of non-caloric sweeteners on the microbiota and the reward system. It found that they reduce microbial diversity, decrease levels of Akkermansia muciniphila and Faecalibacterium prausnitzii, two strains associated with good metabolic health, weaken satiety signals and, paradoxically, do not reduce sugar cravings. They may even sustain them by maintaining the appeal of sweet taste without delivering the expected energy reward⁸.

In the long run, it is preferable to gradually lower the perceived sweetness threshold by becoming accustomed to less intensely sweet flavors.

This is the question no one asks out loud, and the one that most often leads to discouragement. The honest answer is that sensitivity to sweet tastes and the composition of the microbiota begin to rebalance within a few weeks, but returning to a stable state requires two to three months of consistent habits. During the first two weeks, cravings may actually intensify. This is a sign that the bacteria accustomed to sugar are losing ground.

After three to four weeks, most people report a marked decrease in the intensity of their cravings and an increase in their threshold for perceiving sweetness. A piece of fruit can once again taste "very sweet." After three months, sugar cravings become an occasional event rather than a daily presence. Patience and consistency outperform short bursts of intensity. As with many metabolic levers, it is regularity that creates lasting change.

minimiil is neither an appetite suppressant nor a substitute for sugar.

It is a 60 milliliter fermented plant-based shot, specifically formulated to support the mechanisms described in this article: four active probiotic strains (Lactobacillus plantarum, L. rhamnosus, Streptococcus thermophilus, L. delbrueckii), combined with 2.1 grams of prebiotic fibers (agave inulin) in a matrix of fermented organic almond milk with blackcurrant and blueberry.

Organic. Nutri-Score A. No added sugar.

Taken in the morning, it becomes part of a daily ritual that helps initiate blood sugar stabilization and nourish the microbiota over time. INRAE is also working on the next generation of functional probiotics, confirming that this living food approach remains one of the major frontiers of contemporary nutrition¹⁰.

It is not a miracle promise, but a daily source of support to be combined with a fiber and polyphenol-rich diet, sufficient sleep, and an environment that does not undermine your efforts.

references

¹ PubMed
² Inserm
³ PMC
⁴ PMC
⁵ INRAE
⁶ ANSES
⁷ Santé publique France
⁸ PMC
⁹ PubMed
¹⁰ INRAE