How to Use the Weight Regain Prevention Calculator
Going straight back to your old eating habits right after finishing a diet is risky — your metabolism is still running low, so the extra energy gets stored as fat more easily, and rapid weight regain (the "yo-yo" effect) is common. This calculator uses your sex, age, height, current weight, and activity level with the Mifflin-St Jeor formula to estimate your maintenance calories (TDEE), then figures out how long a safe, gradual "reverse diet" from your current intake up to that target would take.
Reverse dieting means increasing your calorie intake in small weekly steps (this calculator uses 100 kcal/week) after a diet ends, rather than jumping straight back up, giving your body time to adapt to the added energy. That gradual pace keeps your metabolic recovery roughly in step with your rising intake, which minimizes weight gain as you work your way back to true maintenance.
Keep in mind the maintenance number here is a formula-based estimate, and actual response varies from person to person. If your weight keeps climbing as you follow the plan, slow down the pace of increases; if it keeps dropping, you can speed up slightly. Weighing yourself at the same time each week and tracking the trend is the key to running a reverse diet successfully.
Frequently Asked Questions
Raising calories quickly can outpace your metabolism, which is still running low after dieting, so the surplus energy gets stored as fat more easily and you can quickly regain weight. Raising calories gradually lets your metabolism recover in step with your intake, minimizing weight gain as you climb back to maintenance.
A small early increase is usually just glycogen replenishment and water retention, not fat gain, so it's expected. But if your weight keeps climbing steadily week after week, slow down your calorie increases and hold at the same level for a few more days.