Why the Same Meal Spikes Differently
Your glucose response is your own
The PREDICT-1 + PREDICT-2 studies (the basis of Zoe) showed something stunning: the same meal can spike glucose 2–4× higher in one person vs another. And the determinants aren't just 'carbs' — they're microbiome composition, circadian timing, sleep the night before, stress, prior meal, even mood.
What shapes YOUR response
Genetics (~30%), microbiome (~20%), meal composition + timing (~20%), sleep (~15%), stress + exercise (~15%). Microbiome variability is the surprise — the same bread fermented by different gut bacteria produces wildly different glucose responses. Hence the 'no universal best diet' finding.
Same food, different response examples
White rice spikes Person A from 90→130 and barely touches Person B (also at 90). A banana flatlines one person and triples another's glucose. Identical breakfast at 8 am vs 10 am produces different responses in the same person. Time of day + sleep state + gut microbiome all enter the equation.
True or False
The glycaemic index of a food reliably predicts its effect on your glucose.
The practical takeaway
Two weeks with a CGM will teach you more about YOUR food responses than years of reading. Test 8-10 staple meals, learn which ones spike you the most, and either modify or reorder them. Pairing + sequence tricks (fibre first, protein first, 10-min post-meal walk) are real and personal.
Key Takeaway
Stop treating nutrition as universal. The same food affects you and your partner differently. A 2-week CGM trial reveals your personal spikes + stable foods, which is an actionable intervention a generic food-label reading never produces.