digest
Short Summary
Main recommendation: Do not treat the study's claim that coffee before breakfast worsens blood glucose spikes as applicable to everyone; the speaker's own n=1 test did not reproduce it, and he stresses that individual responses vary. In his self-experiment, adding a small amount of protein (eggs and butter) before porridge produced the most notable reduction in blood glucose spikes, and a post-meal walk also blunted the rise.
Key Points
- The referenced study found that the group with a bad night's sleep who had coffee before a standardized 75 g oral glucose tolerance test (about 300 mg caffeine via instant coffee) had bigger blood glucose spikes than the bad-sleep group without coffee; contrary to expectations, poor sleep alone did not worsen the response in that study.
- In the speaker's test, the same 300-calorie porridge breakfast produced a large spike when eaten alone, but a slightly smaller spike when preceded by a cup of coffee—the opposite of what the study would predict.
- A 30-minute post-breakfast walk caused the glucose rise to level off and fall quickly, which the speaker attributes to muscles using glucose from the blood.
- The speaker's experiment used a continuous glucose monitor, which he says is expensive and not necessary for most people.
- The speaker relays two explanations the study authors gave for caffeine's effect (adenosine blocking and a synergy with cortisol), but he did not observe the cortisol-driven ramp-up in his own data.
Details Worth Noting
- Concrete instructions: Eat a small amount of protein first, such as scrambled eggs cooked with a little butter, then eat the carbohydrate-heavy food (porridge) afterward; the speaker reports this produced almost no spike.
- Concrete instructions: After eating, go for a good, solid walk of roughly 30 minutes starting about half an hour after the meal to blunt the glucose rise.
- Concrete instructions: If you want to test your own response, a continuous glucose monitor can be used to log readings every 15 minutes via a phone app; the speaker says this is optional and costly.
- The study used a standardized oral glucose tolerance test (75 g glucose in water), whereas the speaker used a real-world 300-calorie breakfast and a cup made from 20 g ground coffee to about 330 g water, which he estimated contained roughly half the caffeine of the study dose.
- The speaker notes he is a habitual coffee drinker, while study participants reportedly abstained from coffee for a few days, which may affect results.
- The speaker says people with a family history of diabetes or type 2 diabetes may have more reason to pay attention to this; he explicitly states he is not a doctor and is not giving health advice.
Bottom Line
Individual blood glucose responses differ, so a study result about coffee timing may not predict your own response; the speaker's data suggests food order and post-meal movement may matter more for him than the coffee-breakfast sequence.
