Kiwi for constipation: how many a day, and how to test it on yourself

Several trials have tested kiwi for constipation. In the biggest trial, constipated adults ate two green kiwis a day for four weeks and gained about one and a half extra complete poops a week (Gearry et al. 2023). Gold kiwis worked too. A British dietary guideline now suggests 2 to 3 kiwis a day for at least four weeks (Dimidi et al. 2025).

How many kiwis a day for constipation? Two, for about four weeks

The largest trial ran in New Zealand, Japan and Italy with 184 adults (Gearry et al. 2023). Some had no gut trouble and some had been constipated for a long time. Everyone spent four weeks on two green kiwis a day and four weeks on psyllium, a fiber powder made from plant seed husks that trials use as the yardstick. The constipated groups gained 1.5 to 1.7 complete poops a week on kiwi. A complete poop is one that comes on its own and leaves you feeling done. Their gut comfort scores improved as well, and the researchers saw no significant side effects.

That gain sounds small on paper. If you're starting from two or three poops a week, one or two more is the difference between a fine week and a week of feeling like a packed suitcase.

The British Dietetic Association guideline turned the trials into a rule of thumb: "Consumption of 2–3 kiwifruit daily for at least 4 weeks may be recommended in constipation" (Dimidi et al. 2025).

What about the skin? The same guideline says nobody has studied it. Skin on gives you more fiber, and possibly more gas. The trials behind the guideline used kiwis without the skin, so peeling or scooping with a spoon is fine.

Gold vs green kiwi for constipation: both worked

The bigger kiwi trials used green kiwis. Gold ones (the sweeter, yellow-fleshed kind sold as SunGold) have their own trials now.

In one, 32 mildly constipated adults ate three gold kiwis a day for four weeks. Their complete poops went from 3.3 a week at the start to 6.3 a week, and the psyllium stretch of the same trial got them to 4.5 (Eady et al. 2019). In a later trial with 56 adults, two gold kiwis a day did as well as a fiber-matched dose of psyllium (Bayer et al. 2022).

So pick the one you like eating. Two a day for a month is a lot of kiwi to get through if you only half like the taste.

Kiwi vs prunes vs psyllium: similar results, and kiwi was the easiest to live with

One US trial put the three head to head (Chey et al. 2021). It took 79 adults who had three or fewer complete poops a week. They got two green kiwis a day, 100 grams of prunes a day (roughly 10 to 12 prunes), or 12 grams of psyllium a day, for four weeks.

All three worked about as well for the main count. The kiwi group reported less bloating, had the fewest side effects, and the fewest people unhappy with what they'd been given.

Pooled across trials, kiwis gave a small edge over psyllium, about a third of a poop more a week, and prunes did about the same as psyllium (Van Der Schoot et al. 2024). If you already like prunes, they're a fair first test. If psyllium has left you bloated before, kiwi is another food you could test.

The kiwi test: a week of notes, then two kiwis a day

Averages tell you what happened to a room full of strangers. Your gut runs on its own schedule, so the only way to know what kiwi does for you is to try it with notes.

Week 0, the baseline. Change nothing. Each day, write down how many times you pooped, your Bristol type, whether you strained, and how bloated you felt. The Bristol chart is a 7-point scale: type 1 is hard little lumps and type 7 is liquid. Types 3 to 5 are the easy ones.

Weeks 1 to 4, two kiwis a day. Keep everything else as steady as you can: same coffee, roughly the same meals. Keep the same notes. Two weeks gives you a first read. The trials ran four, so if week two looks flat, keep going.

Weeks 5 and 6, stop. Drop the kiwis and keep logging. If things drift back toward your baseline, that's a good sign kiwi was doing the work. If they hold, something else may have changed too.

Then compare the weeks:

That sample reads as "helped". There were more poops and softer ones, and things slid back when the kiwis stopped. Bring them back and keep them.

What if kiwis did nothing for you?

It's a common question on Reddit. Two weeks may be too short, since the trials and the guideline both work in four. One stressful week, a trip or a period can swamp the signal, so after a messy month, rerun the test. And some people probably don't respond at all: the trial numbers are averages, and they include the people who got nothing.

If four steady weeks show no change, call it "no change" and test something else.

Other foods that help you poop

A few other foods have trials behind them too, with numbers worth knowing.

• Prunes. About 100 grams a day did as well as psyllium in trials (Van Der Schoot et al. 2024). Start lower if they give you gas.
• Rye bread. In two small trials, rye bread beat white bread by a bit under half a poop a week (Van Der Schoot et al. 2024). The guideline's amount is 6 to 8 slices a day for at least three weeks, and it admits that "may not be realistic" for some people (Dimidi et al. 2025). Swapping your usual bread for rye is a smaller version of the same test.
• Mineral-rich water. In trials, people drinking high-mineral bottled water were 47% more likely to see their constipation improve than people on low-mineral water (Dimidi et al. 2025). The mineral content is on the label.

Pick one, give it the length of a test, and compare it against your baseline week. Stacking all of them at once tells you nothing about which one helped.

Let Gut Twin keep the log

Gut Twin is the kiwi test without the notebook. You pick meals from a food list, log how your gut feels and your poop, and run one small test at a time against your own days. Each test ends with one of four results: helped, no change, worse or unclear. If slow weeks are your main concern, kiwi could be your first test.

What we don't know yet

The kiwi trials are short, usually four weeks, so nobody knows how well the effect holds over months. Most of them were funded by Zespri, the kiwi company, or run by researchers who work with it. Nobody has tested the skin, or what happens after people stop eating kiwis. And the averages hide a wide spread: some people barely move, and nobody can yet predict who will.