Two people eat the same potato: one sees her blood sugar soar, the other barely moves. The same slice of bread produces different responses depending on who eats it, at what hour, after what meal, hosting which microbiome. This variability, long treated as noise, has become an object of study: precision nutrition, which replaces average recommendations with a reading of the individual terrain. It is to nutrition what TCM has always been: the conviction that the body is not an average.
Why average recommendations fail
Nutritional recommendations were built on population averages: a caloric threshold, a macronutrient split, a list of foods to favour. They served to set a frame, but they have a documented limit: they apply to the average, not the individual. The Mediterranean diet is good for the majority, but not for all: some see their blood sugar climb on wholemeal bread, others on potato, others on rice. The average recommendation does not say who.
This is the foundation of precision nutrition: dietary responses are personal, governed by genotype, microbiome, sleep, stress, the previous meal, and metabolic terrain. The blanket “eat a balanced diet” serves public health; it does not always serve the individual patient.
Glycaemic variability: the same bread, two blood sugars
The most spectacular proof of precision nutrition came from the PREDICT study (Zeevi et al., 2015): continuous glucose monitors fitted to hundreds of volunteers showed that the same portion of bread produced glycaemic responses ranging from near-flat to major spike, depending on the individual. The microbiome, background insulin resistance and individual insulin sensitivity explained the response better than the food’s theoretical glycaemic index.
This result has a practical consequence: the glycaemic index remains useful as a general map, but it is not a personal measurement. Wholemeal bread is “low GI” on average; in some people it produces a spike. The only way to know is to measure, not to assume.
The microbiome: conductor of the response
The microbiome is the best individual predictor of dietary response documented to date: the composition of its strains explains a major share of glycaemic, lipid and inflammatory variability. Two people at the same meal do not digest alike because their bacteria do not produce the same metabolites (butyrate, propionate, TMAO). Microbiome diversity is fed by fermentable fibre, pulses, minimally processed foods: it is the best-documented lever of personalisation.
This is also where precision nutrition meets the TCM reading of the microbiome as Spleen Qi: each person’s digestive terrain is unique, and it is what makes a food beneficial or not.
CGM and biomarkers: the practitioner’s toolkit
The continuous glucose monitor (CGM) is the tool that changed practice: worn on the arm for two weeks, it records blood sugar every five minutes and shows in real time the response to each meal. For the patient, it is an immediate reading of what the potato does in them, not in the average. For the practitioner, it is the tool that moves the recommendation from generic to personal.
Other biomarkers complete the picture: fasting insulin, HOMA-IR, lipid profile, CRP for background inflammation, ferritin, vitamin D. Together they sketch the metabolic terrain on which the recommendation is adjusted. Nutrigenomics adds the genetic layer, useful for precise points (caffeine, folate, saturated fats) but not for drawing the whole diet.
TCM: precision nutrition has existed for 2000 years
Chinese dietetics never waited for sensors to assert that two patients do not eat alike: constitutional typology, Spleen terrain, Yin-Yang balance and Jing are all ways of personalising the plate. The Spleen deficiency that congests on raw food, the Yang that flags on cold, the Phlegm that settles on sweet: these are readings of the individual terrain that produce different recommendations per patient, not uniform lists.
The correspondence is not an equivalence: TCM reads the terrain through clinical signs (tongue, pulse, symptoms, morphology), precision nutrition reads it through biomarkers. But the conviction is the same: the average serves the average, not the individual, and the right recommendation starts from the terrain.
Frequently asked questions about precision nutrition
Is a CGM useful for everyone?
No. A CGM is chiefly useful in people with metabolic terrain (prediabetes, diabetes, insulin resistance) or within a supervised precision project. In the healthy subject with no specific goal, it adds information without changing the fundamentals. It is a measuring tool, not a judgement.
Does my microbiome determine my ideal diet?
Partly: microbiome composition is one of the best predictors of glycaemic and lipid response, but it does not produce a fixed diet. The gestures that diversify the microbiome (fermentable fibre, pulses, minimally processed foods) are the same for almost everyone; what changes is individual sensitivity to certain foods.
Does precision nutrition replace classic recommendations?
No, it refines them. General recommendations (variety, minimal processing, fibre, adequate protein) remain the base; precision adjusts individual responses (this starch suits me better than that one, this meal timing favours me). It is a layer of adjustment, not a paradigm shift.
How do I know which food suits me without a sensor?
Through structured observation: a meal diary noting satiety, energy and digestion for 2 to 3 weeks reveals patterns (this food leaves me heavy, that one keeps me going). It is not a glycaemic measurement, but it is a reading of the terrain that TCM has practised for a long time. The practitioner can also use blood biomarkers (fasting glucose, insulin, lipids) to orient.
The plate that starts from the terrain
Precision nutrition is the recognition that the body is not an average: the same plate has different effects depending on the terrain. The tools (CGM, biomarkers, microbiome) let us measure what TCM read through clinical signs. But precision serves the fundamentals, it does not replace them: vegetables, fibre, adequate protein, minimal ultra-processing hold for everyone. What changes is the individual dose.
In the Yin Shi app, the food sheets give the glycaemic index, fibre density and thermal nature of each product: the terrain is read in the details, not in the average.
Further reading: the glycaemic index and the sweet flavour, the microbiome as Spleen Dampness, insulin resistance as Spleen deficiency, nutrigenomics, and the Mediterranean diet through the TCM lens.
To go further
Yin Shi ecosystem resources directly related to this article.