Drug & supplement interaction

Zone Diet + Orlistat

Orlistat brand names: Xenical, Alli.

No Known Interaction
Medically reviewed by · Updated June 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Zone Diet and Orlistat in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Zone Diet and Orlistat

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Orlistat and Zone Diet in our sources. This does not guarantee that the combination is completely free of risk — research on Zone Diet alongside specific medications may be limited.

Worth understanding: our licensed dataset holds no drug-interaction record for Zone Diet at all — not against Orlistat, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

Zone Diet is an eating pattern rather than something you take. Ask your pharmacist or doctor before changing how you eat while on a prescribed medicine: some medicines are dosed around meals, and a change in diet can change how they work. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Zone Diet safety at a glance

Zone Diet overall Use caution Generally safe for healthy adults but it is restrictive and may not suit everyone.
Pregnancy Use caution Calorie- or carb-restricted diets may not meet pregnancy nutrient needs, so check with your doctor first.
Breastfeeding Use caution Nursing needs extra calories and nutrients, so discuss any restrictive diet with your provider.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Orlistat and Zone Diet? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Orlistat’s Own FDA Label Lists

This is not an interaction — none of it involves Zone Diet. These are the most notable effects listed in the ADVERSE REACTIONS section of Orlistat’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you follow Zone Diet and take the medicine. 10 of them are worth acting on rather than waiting out — marked below.

  • Bleeding in the gut Worth acting on
  • Low blood sugar Worth acting on
  • Pancreatitis Worth acting on
  • Wheezing Worth acting on
  • Low mood Worth acting on
  • A severe allergic reaction Worth acting on
  • Hives Worth acting on
  • Liver problems Worth acting on
  • Bleeding or bruising Worth acting on
  • A higher chance of infection Worth acting on

Showing the 10 most notable of 28 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Orlistat. Read the label on DailyMed › Where a percentage is shown, it is the share of 25,755 voluntary FDA FAERS reports for Orlistat that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Zone Diet’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Zone Diet side to compare — that is a limit of the record, not a statement that Zone Diet has no side effects.

Everything else you take

See Every Supplement That Interacts With Orlistat

This page covers Zone Diet only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Orlistat page lists 18 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Fish Oil (moderate) and Glucomannan (moderate).

By severity: 1 major · 8 moderate · 9 minor.

From our pharmacist’s overview on the Orlistat page

“People who take Orlistat (Xenical, Alli) for weight loss often browse the very supplement aisle where fiber products and fish oil sit, and both show up on this page, so it deserves genuine attention before you mix anything in. Nearly all 18 ingredients on file can change how oral medications absorb from the gut, and the single major-ra…”

Reviewed by 2 · Jul 18, 2026

Open the Orlistat interaction page

How much people look this up

Where Zone Diet and Orlistat Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Zone Diet
Steady interest

#912 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Orlistat
Top 25%

#519 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Zone Diet reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Zone Diet and Orlistat records this page draws on were last updated June 22, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Eating pattern

About Zone Diet

What is Zone Diet?

  • Weight loss
  • Blood sugar control
  • Reducing inflammation
  • Heart health support
  • Improving energy and athletic performance

The Zone Diet is an eating plan, not an herb or supplement, that aims to balance every meal into roughly 40% carbohydrate, 30% protein, and 30% fat. It can help some people lose weight and improve diet quality, mostly by encouraging portion control and lean proteins, but evidence that its specific ratio is better than other balanced diets is limited. Talk with your doctor, pharmacist, or a dietitian before starting, especially if you have a medical condition.

Eating plan (whole-food meals and snacks), meal-delivery services, prepackaged bars and shakes

An interaction check asks whether these two react with each other — it does not ask whether Zone Diet is a good idea for someone in your situation. Here is what our Zone Diet record says about it on its own.

Zone Diet: dosing

There is no pill or standardized "dose" for the Zone Diet because it is an eating pattern, not a supplement. Instead, the plan is followed by structuring meals around the 40% carbohydrate, 30% protein, 30% fat idea and eating regular, portion-controlled meals and snacks.If you use Zone-branded products like bars or meals, follow the label directions.

From our Zone Diet monograph — the full record covers uses, side effects and every documented interaction.

Read the full Zone Diet monograph & all interactions
Medication

About Orlistat

What Is Orlistat Used For?

Brand names: Xenical, Alli

Xenical and prescription-strength orlistat are approved to help obese adults lose weight and keep it off when used with a reduced-calorie diet. They are intended for people with a body mass index (BMI) of 30 or higher, or 27 or higher if other risk factors such as high blood pressure, diabetes, or dyslipidemia (abnormal cholesterol or fat levels in the blood) are present.

Alli is the over-the-counter version, approved for weight loss in overweight adults 18 and older when used with a reduced-calorie, low-fat diet and exercise program.

Most-Reported Side Effects for Orlistat

From FAERS, the FDA’s public side-effect reporting system (25,755 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Rectal discharge 2,434 reports
Gastrointestinal disorder 2,186 reports
Constipation 1,991 reports
Diarrhea 1,960 reports
Weight increased 1,944 reports
See full Orlistat drug information
Keep checking

Other Drugs & Zone Diet

Browse every other medication we’ve checked against Zone Diet — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

We also checked Zone Diet against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Zone Diet list.

See the full Zone Diet interactions page
See every supplement checked against Orlistat, ranked by severity
Evidence & sources

Zone Diet References

The 4 references that drive our Zone Diet monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Fontani, G., Corradeschi, F., Felici, A., Alfatti, F., Bugarini, R., Fiaschi, A. I., Cerretani, D., Montorfano, G., Rizzo, A. M., and Berra, B. Blood profiles, body fat and mood state in healthy subjects on different diets supplemented with Omega-3 polyu
  2. Gardner CD, Kiazand A, Alhassan S, et al. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study: a randomized trial. JAMA. 2007 Mar 7;297(9) PubMed
  3. McAuley KA, Hopkins CM, Smith KJ, et al. Comparison of high-fat and high-protein diets with a high-carbohydrate diet in insulin-resistant obese women. Diabetologia. 2005 Jan;48(1):8-16. Epub 2004 Dec 23. Erratum in: Diabetologia. 2005 May;48(5):1033.
  4. Jarvis M, McNaughton L, Seddon A, Thompson D. The acute 1-week effects of the Zone diet on body composition, blood lipid levels, and performance in recreational endurance athletes. J Strength Cond Res. 2002 Feb;16(1):50-7. DOI

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Following Zone Diet While Taking Orlistat: Common Questions

Is it safe to follow Zone Diet while taking Orlistat?
We do not list a known interaction between Zone Diet and Orlistat. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Does Orlistat interact with any supplements?
Yes. Orlistat has documented interactions with 18 supplements in our database — Zone Diet is not one of them. The Orlistat interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Zone Diet monograph Uses, safety profile, and every drug interaction in one place Orlistat drug information The full plain-English guide to this medication Orlistat supplement interactions Every supplement checked against Orlistat, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Orlistat and Zone Diet?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.