Press kit
In testing · coming to iPhone
Join the betaIn one sentence
Nesteia is a fasting timer for iPhone that tells you what research has measured in healthy adults at each hour of a fast, with the paper cited and how confident the science is.
In one paragraph
Nesteia is a fasting timer for iPhone. It runs daily windows from 12:12 to one meal a day, water fasts of 24, 36, 48 and 72 hours with refeed days, and custom lengths from 12 to 72 hours; the 96 and 120-hour plans are only for people fasting under a clinician and are confirmed before every such fast, and nothing passes 120 hours. As the hours pass, it names the body stage that studies measured at that point in healthy adults: eleven stages, from the fed state to refeeding, each with its sources and a confidence label. It does not read your body and promises no outcome. Strata badges are earned by ending a plan at its length, never by going longer, and the safety rails are part of the timer, from an 18+ gate and screening questions to a stop card one tap away. The history stays on the iPhone, with no account, no server, no analytics and no tracking.
Key facts
- Name
- Nesteia. Listed as Nesteia: Fasting Timer, with the subtitle Fasting, with the evidence.
- Status
- In testing · coming to iPhone. Not yet on the App Store, and there is no release date to give. The public beta is open on TestFlight, where purchases are free test purchases.
- Platform
- iPhone, iOS 26 or later. English (UK). Health & Fitness.
- Price
- Free, with an optional Nesteia Pro. Prices at launch: £4.99 a month; £39.99 a year, with a 14-day free trial for new subscribers; or £99.99 once for Lifetime.
- Free and Pro
- Free, for good: every daily window, the 24 and 36-hour plans, custom lengths and stages to 36 hours, the Live Activity, widgets, History and its log, and export. Pro adds the 48 and 72-hour plans, the supervised 96 and 120-hour plans, custom lengths to 72, every stage past 36 hours, all the Strata layers and families, weight trends and optional iCloud sync.
- Stages
- Eleven body stages, from the fed state to refeeding, each with what studies measured, how it may feel, what to do and a confidence label. Twenty-four sources, primary studies and reviews plus two clinical guidelines (ASPEN 2020 and NICE CG32), all listed on the stages page.
- Ceiling
- 120 hours on every timer, plan, edit, import, link and widget; a running fast ends itself there. Anything over 72 hours only with a clinician's supervision, confirmed before each such fast.
- Privacy
- No account, no server, no analytics, no tracking. The history stays on the iPhone; iCloud sync is an optional Pro setting, off by default, into the person's own private iCloud, which nobody at Nesteia can see.
- Age
- Adults only, with an 18+ gate before the timer.
- Publisher
- Serhat Dereli, a sole trader trading as Nesteia, Bromley, UK.
- Website
- nesteia.app · What's new in the beta
- Contact
- serhatdereli@icloud.com
Nesteia is not a medical device
It gives no medical advice, diagnosis or treatment. It describes what research measured in other people, not the reader's body. It is for adults, and not for anyone who is pregnant or breastfeeding, underweight, or has a history of an eating disorder. The safety page sets out every rail the timer has.
Downloads
Free to use in coverage of Nesteia. Please use them as they are.
App icon and mark
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App icon
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App icon, dark
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Mark
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Mark, for dark backgrounds
The wordmark is the word Nesteia set in Instrument Serif beside the mark, both in ink, as in the header of this page; the favicon draws the mark in tide. The share card used for link previews is at nesteia.app/og.png (1200 × 630).
Screenshots
From a test build on a 6.9-inch iPhone display, 1320 × 2868 px, light appearance. The captions are the ones written for the App Store.
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The stage you are in, not a score
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Each stage and how sure the evidence is
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A layer for each plan kept at its length
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One quiet moment when a fast ends
Brand colours
Tide is the one accent, for actions, links and the ring. Sand is warm and belongs to Strata and Pro; dusk is cool and belongs to the stages and their confidence. Ember appears only beside safety copy. Each colour has a light and a dark value.
- Surface#F4F3EE · #0E1315
- Ink#171B1D · #E9E7E0
- Stone#666E72 · #8C9498
- Tide#236A76 · #5CB5C1
- Sand#775F31 · #D1B07A
- Dusk#585E8E · #A3A9E0
- Ember#AC5335 · #E38A66
Type: Instrument Serif for headings and the timer's numerals, Inter for text, both under the SIL Open Font Licence.
Please don't
- Describe Nesteia as a diet or slimming app. It names no body-weight goal and makes no claim about body weight.
- Call it a medical app, or say it diagnoses, treats or prevents anything. It is not a medical device.
- Say it tells you what is happening in your own body. It describes what studies measured in healthy adults.
- Suggest it to anyone under 18, pregnant or breastfeeding, underweight, or with a history of an eating disorder.
- Say it is on the App Store before it is, or quote prices other than the launch prices above.
- Name a company behind it. It is published by Serhat Dereli, a sole trader trading as Nesteia.
- Recolour, redraw or crop the icon or the mark.
Contact
For interviews, questions or a beta invitation, write to serhatdereli@icloud.com. Nesteia is made by Serhat Dereli, a sole trader trading as Nesteia, Bromley, UK.