How distance and visibility affect food consumption without conscious awareness.
What the evidence says
- 2019 Cochrane review: food placed farther away reduces consumption — SMD −0.60 (95% CI −0.84 to −0.36), a moderate effect the review itself rates LOW-CERTAINTY (its GRADE footnotes cite risk of bias among the reasons) (corrected 2026-09-10 from ”mainly for inadequate blinding”: that attribution is in a held abstract file that does not match the paper, and the paper’s text never mentions blinding)[1]
- The proximity effect may not depend on conscious engagement — the authors’ own hedge, twice: they report ”the first evidence that the proximity effect may not rely on conscious engagement to affect behaviour” and that it ”may operate non-consciously”, crediting the concept to Hollands et al. 2016. The evidence is that few participants reported noticing the manipulation — which is about attention, not about being unable to override it[2]
- Guyenet advises limiting visible food, on a premise he asserts rather than a finding he reports — the held text says ”limit the amount of visible food in your personal food environment” and, of tempting items, ”get rid of” them. He does not contrast visible with hidden food anywhere this library holds, and the intervention he prescribes is removal, not concealment. Still NOT the mechanism behind the distance findings below, which `cpi03` and `cpi07` both trace to effort rather than salience — see the Sourcing note before repeating any of it[3]
- Reducing available options also reduces selection — SMD −1.13 (95% CI −1.90 to −0.37), a large effect from 3 studies (n=154), also rated low-certainty[1]
- REMOVED 2026-08-31: “Effect persists over time, not just novelty” — cpi03 makes no persistence claim, and none of this file’s sources tests durability. Recorded rather than silently dropped; restore only against a source that measured it.
- Specific distances tested: 20cm vs 70cm showed meaningful differences (arm’s reach vs standing up)[2],[4]
- Three distances were tested, snacks at 20cm, 70cm or 140cm. In Study 1 (N = 77) both distant conditions reduced the probability and the amount of intake against the 20cm condition; Study 2 (N = 54), which also rated effort and salience, replicated this (corrected 2026-09-19, following `cpi07`: n=77 is Study 1, which measured intake only, not the study that examined effort and salience)[4]
- Among people who did take the snack, distance made no significant difference to the amount: ”Neither study found significant effects of proximity on amount consumed among those who took the snack”. This sits beside the `cpi07` result above without contradicting it only if `cpi07`’s amount counts non-takers as zero; that is not checked here, so state each finding with its own measure (added 2026-09-10, from FC2’s reading of companion 433)[2]
- The same work measured perceived effort and visual salience separately and found distance moved effort but not salience — which is what licenses the effort reading rather than a visibility reading[4]
- Compensatory behaviour was measured only as food craving (”risk of compensatory behaviour as measured by food craving”): distance produced ”no unintended effects in terms of increased craving”, and the authors conclude ”without risk of compensatory behaviour”. Later eating was not measured (corrected 2026-09-19, following `cpi07`, from ”did not increase craving or produce later compensation”)[4]
- Distance moved perceived effort but not salience, measured twice, by different groups: `cpi07` (n = 54) and `cpi03` (n = 159 and 246) each rated effort and salience separately, and each found effort moved while salience did not. That is consistent with an effort reading; neither paper tested mediation, so ”works through effort” is this library’s inference, not either paper’s finding (corrected 2026-09-19 from ”Distance effect works through perceived effort, not reduced visual salience”)[4],[2]
- 18 of 24 Cochrane studies examined proximity interventions[1]
- Proposed in the Cochrane review’s background, not tested by it — effort minimization — “humans tend to take the least effortful course of action without the need for conscious deliberation”[1]
- The Cochrane meta-regression names four conditions under which the proximity effect was greater, and all four qualify it. The review’s own sentence: the effect was greater ”the farther away the product was placed; when only the targeted product(s) was available; when participants were of low deprivation status; and when the study was at high risk of bias”[1]
- The equity question, which the review says its data cannot settle: the third moderator compares low-deprivation samples with samples mixed in deprivation, not with high-deprivation ones, and the authors write that ”These factors limit assessment of social differentiation in effects relevant to health equity” (corrected 2026-09-10 from ”larger effects among low-deprivation populations mean these interventions may benefit already-advantaged groups more”: that inference is in `cpi01`’s `pmc-excerpts.txt`, not in the paper)[1]
- The fourth is the one that bears on the headline number. An effect that grows with a study’s risk of bias is an effect whose size depends partly on how the studies were run, and it belongs beside the SMD wherever the SMD is quoted[1]