# Switching diets without losing your history *Guide · 2026-10-22 · https://undiet.app/guides/switching-diets* What usually happens to your data when you change diets, and how to keep every attempt as a period on one timeline so the question of what works for you has an answer. ## Most trackers reset Change your plan in most apps and the old one is gone: a new goal, a new start date, a fresh graph. Six months of real data turn into a before. Undiet does the opposite. Every program you mark becomes a period on one timeline, and the weight curve runs over all of them. ## Periods, not programs When you mark a program from the catalog, a period starts. When you mark another, or none, the first one ends and stays, with its own start, end, weigh-ins and change. So a six week [fasting](https://undiet.app/diets/fasting-16-8) stretch and a three month [keto](https://undiet.app/diets/keto) stretch sit next to each other on the same axis, each with its own numbers. ## The no diet period counts The months between programs are the part most apps throw away. Undiet keeps them as a period of their own. What happens after you stop is often the most useful thing the graph shows. It is where the honest comparison lives. ## Switching is data, not failure Trying something, finding it did not fit, and moving on is how most people actually arrive at what works. A timeline with four periods on it is a record of learning, not of giving up. The feeling comb makes the record readable: the period you could not live with shows up as a row of heavy days, whatever the scale did. ## Programs with built in switches Some programs are rotations by design. [Undiet 90](https://undiet.app/diets/undiet-90) cycles structured phases with recovery breaks over ninety days, and [Whole30](https://undiet.app/diets/whole30) is a thirty day block followed by reintroduction. They fit the same timeline. Each phase can be its own period, or the whole program one period, whichever reading you want later. ## How to switch cleanly Open the catalog page of the new program and tap I am on this. The old period closes that day and the new one opens; nothing else changes. If you are stopping without a replacement, mark no diet. The line keeps going, and the stretch gets the same care as any program. ## Reading it back later Scrub along the curve with a finger and the readout follows: the weigh-in, the date, the program and the day you were on. Period labels light up as you pass through them. The free app shows the last 90 days. [Plus](https://undiet.app/plus) opens the graph to the whole journey and adds the stats for every period: the change, the pace, the check-ins and the average feeling. ## Choosing the next one If the next period is an open question, [Find my diet](https://undiet.app/find-my-diet) narrows the 98 programs to a shortlist in five taps, and [Mediterranean](https://undiet.app/diets/mediterranean) is where many people land after a strict stretch. Whatever you pick, mark it. The timeline is only honest if it is complete. ## Programs in this guide - [Keto](https://undiet.app/undiet/diets/keto.md): A very low-carbohydrate, high-fat approach that pushes the body to run on fat instead of glucose. Structured and demanding, especially at the start. - [Fasting 16:8](https://undiet.app/undiet/diets/fasting-16-8.md): Less a diet than a schedule: eating is kept within a set window (a common one is 8 hours). What you eat is up to you. - [Mediterranean](https://undiet.app/undiet/diets/mediterranean.md): A way of eating built around vegetables, legumes, whole grains, olive oil and fish, with less red meat and sugar. Less a strict plan than a pattern, which is why people stay with it. - [Undiet 90](https://undiet.app/undiet/diets/undiet-90.md): A 90 day rotation program that cycles structured eating phases with recovery breaks. - [Whole30](https://undiet.app/undiet/diets/whole30.md): A strict 30-day elimination of sugar, grains, dairy, legumes and alcohol, then a structured reintroduction. More guides: https://undiet.app/undiet/guides.md. Find my diet in five taps: https://undiet.app/find-my-diet. Free on iPhone (https://apps.apple.com/app/id1490849895) and Android (https://play.google.com/store/apps/details?id=be.krnic.undiet). Undiet describes programs and records what you log. It does not give medical advice. --- Any diet. No calorie counting. Your weight, your effort and every diet you try, on one timeline. Undiet is a tracking companion, not a medical service. For people aged 16 and over. Made by Krnic CommV, Gent, Belgium. Contact: undiet@krnic.be. Privacy: https://undiet.app/privacy · Terms: https://undiet.app/terms · Delete your account: https://undiet.app/delete-account · Support: https://undiet.app/support