The Low-Plastic Week, in Plain Words
In April 2026, a team in Perth published a small randomised trial with an unusual design. They did not ask people to eat less, or to eat differently in any way that would show up on a scale. They changed what their food had touched on its way to the plate, and then measured what came out in their urine seven days later. The reel had room for the headline. This page has room for what each of the five groups actually changed, and for what the trial cannot tell you.
The basics
What the trial was
Sixty healthy adults, aged 18 to 60, in Perth, Western Australia. Randomised into five groups of twelve. Seven days. Everyone finished.
Energy intake was held steady by design. This was never a diet study. What changed was plastic contact.
Urine was collected three times a day on four non-consecutive days and corrected for creatinine, the standard way to stop a concentrated or dilute sample from flattering the result.
One detail: the paper also contains a separate 211-person observational group. Everything on this page comes from the randomised trial unless it says otherwise.
The part the reel promised
What each of the five groups changed
| Group | What they were given |
|---|---|
| 1 | Low-plastic food: ingredients produced, processed, packaged and supplied with minimal to no plastic exposure |
| 2 | Low-plastic food and kitchenware |
| 3 | Low-plastic personal-care products only (soap, shampoo and the like). Food unchanged |
| 4 | Low-plastic food, kitchenware and personal-care products |
| 5 | Control: no change at all |
The food came from more than a hundred producers chosen to keep plastic contact low from farm to plate. That is not a shopping list anyone can copy, and the authors say so themselves.
Read the table again and notice what is missing. Three of the four groups that changed something had their food changed. There was no group that changed only their kitchenware. So if you came here wanting to know whether swapping your containers does anything on its own, this trial cannot tell you. Nobody tested it.
The results
What moved, and by how much
In the groups given the low-plastic food, compared with the control group:
- −37.5%mono-n-butyl phthalate95% CI −55.6 to −12.0 · P=0.007
- −53.5%monobenzyl phthalate95% CI −72.7 to −20.6 · P=0.005
- −59.7%bisphenol A95% CI −82.5 to −6.87 · P=0.033
Group 3, the soap-and-shampoo group who changed nothing about their food, still showed a fall in mono-n-butyl phthalate compared with no change. But it moved no bisphenol at all.
That contrast is the useful part of the whole trial. The personal-care swap did something, and it did something narrow. The food swap did more, across more of the chemicals measured.
The honest part
The one that didn't move
One family of chemicals, DEHP, did not fall. If anything it drifted upward over the week.
The authors flag this as unexpected and say plainly that they cannot explain it. They do not bury it, and neither will we. A result that only ever points one way is usually a result that has been tidied.
Read it carefully
Four things this does not mean
It does not mean anyone got healthier. The trial measured chemicals leaving the body in urine. It did not measure a single health outcome, and seven days is far too short to produce one. Nothing changed in body composition, inflammation markers, blood fats or fasting glucose. A lower level in urine is evidence that less went in, not evidence that a harm was avoided.
It does not mean plastic exposure was eliminated. Exposure continued throughout, in all five groups. One whole chemical family did not fall at all.
It does not mean all plastics behave the same. The effect came from food. The personal-care swap moved a different, narrower set of chemicals. And kitchenware alone was never tested.
It is not a shopping instruction. Twelve people per group is very small. The food supply used was unusual and built for the trial, and the authors themselves name cost and availability as limits.
What you can do
Calm, practical steps
Nothing here is urgent, and nothing here needs buying.
- Food that has touched less plastic is the lever this trial actually tested. Loose produce, things bought at a counter rather than under film, fewer heavily packaged and canned items. That is where the broadest effect came from.
- Heat is the known accelerant. Not tested in this trial, but established elsewhere: don't microwave food in plastic, and don't leave plastic-packed food in a hot car or in the sun.
- Changing soap and shampoo is a real but narrow lever. It moved one phthalate here and no bisphenol. Worth knowing before anyone sells it to you as the whole answer.
- Your containers are an open question. We would rather say that than guess. If you are replacing them anyway, glass and stainless steel are easy defaults, but this trial is not evidence either way.
- Nothing on this page is a reason to throw anything away today. Replace things as they wear out.
Where this comes from
Sources
- Plastic Exposure Reduction Transforms Health (PERTH) Trial. Nature Medicine 32(5):1871–1883, 2026. doi 10.1038/s41591-026-04324-7. Open access. Trial registration ACTRN12622001252707.
- Context on the wider evidence (that markers of this kind reliably fall when people reduce exposure, while the health benefit remains unproven): a 2026 narrative review in Ecotoxicology and Environmental Safety 318:120272, doi 10.1016/j.ecoenv.2026.120272. Its own percentage ranges are not quoted here: it pooled no data and reported no confidence intervals.
From Evmara
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