Restated: you want to know if intermittent fasting will give you sharper focus during desk work, so you can decide whether to change your eating schedule. Sub-questions and plan: 1. What do controlled studies say about fasting and cognition? Queries: "intermittent fasting cognition randomized controlled trial", "time restricted eating cognitive performance systematic review" Sources: PubMed-indexed systematic reviews and RCTs. Credibility test: is it a review of human trials, not rodent studies or opinion pieces? 2. Does the effect apply to knowledge work specifically? Queries: "fasting attention office workers study", "glucose cognition mental work" Sources: cognitive psychology journals. Credibility test: measured focus tasks, not self-reported "energy". 3. What are the confounders (sleep, caffeine, total calories)? Queries: "fasting cognition confounders sleep caffeine" Sources: methods sections of the studies from step 1. Credibility test: the study controlled for sleep and caffeine intake. 4. What do experienced practitioners report, with what biases? Sources: community reports only after the science steps. Credibility test: treat as hypothesis generators, never as evidence. Do NOT rely on: diet influencer posts, headline-only news writeups ("study shows fasting boosts brainpower!"), or any source selling supplements. Synthesis order: systematic reviews first, then one or two RCTs, then confounders. If reviews find no effect in healthy adults, stop there. If effects show up only in specific groups (sleep-deprived, older adults), check whether you fit the group before changing your schedule.