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About this tool
Pick two non-consecutive 500-600 kcal days, see the whole week's calories, and get the weekly deficit and expected rate of loss.
The 5:2 Fasting Week Planner turns the pattern's two rules — eat normally on five days, restrict to about 500 kcal for women or 600 kcal for men on two non-consecutive days — into a full week of numbers. It estimates maintenance calories with the Mifflin-St Jeor equation and an activity factor, then works out weekly intake, the deficit against maintenance, and the rate of loss that deficit implies at the conventional 7,700 kcal per kilogram of body fat. Consecutive restricted days and rates faster than the usual 0.5–1 kg a week range are flagged.
Open 5:2 Fasting Week Planner on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Shows total intake, average daily calories and the deficit, so the five normal days are accounted for.
Uses Mifflin-St Jeor with an activity factor rather than a generic 2,000 kcal assumption.
Flags back-to-back restricted days and projected losses above 1 kg a week.
About 500 kcal for women and 600 kcal for men — roughly a quarter of a typical day's intake. The other five days are eaten normally, which is what distinguishes 5:2 from continuous calorie restriction.
No — the pattern is built around two non-consecutive days, with at least one normal day between them. Back-to-back restricted days are harder to sustain and give up the main practical advantage of 5:2, which is that a difficult day is always followed by a normal one.
It depends entirely on your maintenance calories, because the weekly deficit is roughly twice the gap between your maintenance figure and the restricted-day allowance. Someone maintaining on 2,000 kcal creates a deficit near 3,000 kcal a week, which is about 0.4 kg at the conventional 7,700 kcal per kilogram of fat. Results are typically slower than the arithmetic suggests once the five normal days drift upwards.
Protein and high-volume vegetables give the most food per calorie: eggs, dal, curd, fish, chicken, clear soups and large salads. Water, black coffee and plain tea are unrestricted. Spreading the allowance across two small meals rather than one is usually easier to stick with. This is general information — anyone with diabetes, an eating disorder history, or who is pregnant should speak to a doctor before restricting intake.