10/ All data and code are openly available:
🔗 osf.io/nb5mj/
Open access paper:
📄 doi.org/10.1037/bul0...

9/ Overall takeaway:
🧠 Cognitive performance is resilient.
⏱️ Short-term fasting appears safe for thinking and decision-making.
⚖️ But fasting length, timing, and individual factors matter.

8/ Still, children and teens may be more vulnerable.
Studies consistently show breakfast benefits attention and memory in younger learners.
🥣 For kids, skipping breakfast can impair performance; for adults, not so much.

7/ So should you avoid fasting before mentally demanding tasks?
For most healthy adults: No need.
Your brain seems to function just as well after skipping a meal—at least in the short term.

6/ Interestingly, time of day mattered too—fasted participants tested later in the day performed a bit worse.
Possible reason? Circadian rhythms and glucose availability fluctuate across the day.

5/ But context matters.
We found three factors that slightly influenced results:
🕐 Fasting duration: longer fasts = small temporary declines.
👶 Age: younger participants were more affected.
🍔 Stimuli: fasted people performed worse on food-related tasks.

4/ That means: Attention, memory, reasoning, and other executive functions stayed intact.
Even moderate hunger didn’t impair mental performance.

3/✅ Main finding:
Cognitive performance remained remarkably stable when fasted.
Average difference between fasted and fed participants:
g = 0.02 (95% CrI [−0.05, 0.10])
In plain terms: no meaningful change in cognitive ability.

2/ Fasting—whether overnight or for a day—is often praised for its health benefits.
But many worry it might cloud thinking.
We analyzed 222 effect sizes from 3,484 participants to test that assumption directly.