About the Reverse Diet Calculator
Reverse dieting is the practice of raising calories slowly after a fat-loss phase instead of jumping straight back to maintenance. This calculator builds the schedule: enter the calories you eat now, the maintenance level you want to reach, and how fast to add food — either a fixed number of calories per week or a percentage of your current intake — and it shows every week’s target and how long the process takes.
It is popular with physique competitors after a contest prep, and with anyone coming off a long diet who wants to limit rapid regain while their appetite and routine settle. Many people also use it simply to rebuild their calories to a sustainable level after years of chronic under-eating.
A typical pace is about 50–150 kcal per week, often added mostly as carbohydrate and fat while protein stays steady. Research does not show that reverse dieting “repairs” metabolism; the benefit is controlled, predictable weight change. A faster return to maintenance is also a reasonable choice — use the calculator to compare both.
With the default inputs, the weeks to reach maintenance is 7. Change any value above to recalculate instantly.
How to use the reverse diet calculator
- 1Enter the calories you eat now at the end of your diet.
- 2Enter your estimated maintenance calories as the target.
- 3Choose a fixed calorie step or a percentage per week.
- 4Follow the weekly schedule, adding the extra calories mostly from carbs and fats.
- 5Weigh yourself regularly and hold a step for an extra week if weight climbs quickly.
Formula and method
With a fixed step, calories rise by the same amount each week, so the number of weeks is the gap between current and target calories divided by the weekly step, rounded up. The last week is capped at the target so you never overshoot.
With a percentage step, each week’s calories are the previous week’s times (1 + p), which compounds — early steps are smaller and later steps larger. The number of weeks is found with logarithms and rounded up. Neither method adjusts for body-weight changes; re-estimate maintenance if your weight moves more than you expect.
- C₀
- Current daily calories
- C_k
- Daily calories in week k
- T
- Target maintenance calories
- s
- Fixed weekly increase in kcal
- p
- Weekly percentage increase (as a decimal)
Worked examples
1,600 to 2,300 kcal at +100 kcal per week
The gap is 700 kcal. Adding 100 kcal each week reaches 2,300 kcal after 700 ÷ 100 = 7 weeks. Week 1 is 1,700 kcal and at the halfway point (week 4) you eat 2,000 kcal.
Post-contest reverse at 5% per week
Each week multiplies calories by 1.05: 1,890, 1,984.5 and so on. ln(2,600 ÷ 1,800) ÷ ln(1.05) ≈ 7.5, so it takes 8 weeks, with the final week capped at 2,600 kcal.
Faster reverse: 150 kcal steps
A 700 kcal gap at 150 kcal per week needs 700 ÷ 150 = 4.67, rounded up to 5 weeks. The last step is only 100 kcal because the plan stops at the 2,100 kcal target.
Frequently asked questions
What is a reverse diet?+
A reverse diet is a planned, gradual increase in calories after a period of dieting, usually 50–150 kcal per week, until you reach maintenance. It aims to limit rapid fat regain and help appetite and habits adjust.
How many calories should I add per week when reverse dieting?+
Common guidance is 50–150 kcal per week, or about 2–5% of current intake. Leaner or smaller people often use smaller steps; people with a lot of weight to maintain can go faster.
Does reverse dieting fix a slow metabolism?+
There is little evidence that reverse dieting speeds up metabolism beyond what eating more naturally does. Energy expenditure rises as you eat more and regain some weight, whether you increase slowly or quickly.
Will I gain weight during a reverse diet?+
Some scale weight gain is normal — mostly water and glycogen as carbs increase, plus food in the gut. Rapid, continuing gain suggests you are above maintenance; pause the increases for a week or two.
How long should a reverse diet last?+
Most last between 4 and 16 weeks depending on how far below maintenance you are and the size of each step. Very long reverses offer little extra benefit, so many coaches aim to reach maintenance within about 2–3 months.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.