Your BMR (Mifflin-St Jeor).

BMR (Basal Metabolic Rate) is roughly the energy your body would burn over 24 hours at complete rest. We use the Mifflin-St Jeor equation¹, the most accurate widely-used formula for healthy adults.

Male:    BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + 5
Female:  BMR = 10·weight(kg) + 6.25·height(cm) − 5·age − 161

We store your birthday, not your age, so we recompute age every time we run the formula. Your numbers stay correct as years pass without you having to edit anything.

Activity multiplier.

Your BMR is what your body spends at rest. Real life moves around; we multiply your BMR by a factor based on your typical activity.

• Sedentary, little or no exercise: ×1.2
• Light, 1–3 days/week: ×1.375
• Moderate, 3–5 days/week: ×1.55
• Active, 6–7 days/week: ×1.725

Maintenance.

Maintenance = BMR × activity multiplier. That's roughly how many calories you'd eat to neither gain nor lose weight.

Daily target.

Your target is your maintenance, shifted up or down based on your goal weight and how fast you want to get there. We use the "1 kg of body weight ≈ 7,700 kcal" approximation² and divide across seven days.

direction = sign(goal_weight − current_weight)
             // −1 lose,  0 maintain,  +1 gain

target = maintenance + direction × weekly_rate × 1100

If you're maintaining, the second term is zero. Your target equals your maintenance.

Protein, carbs, fat.

Once we know your daily target, we split it into protein, carbs, and fat.

• Protein: 25% of target ÷ 4 kcal/g
• Carbs: 50% of target ÷ 4 kcal/g
• Fat: 25% of target ÷ 9 kcal/g

These percentages sit mid-range within the U.S. Institute of Medicine's Acceptable Macronutrient Distribution Ranges (AMDR)³, broadly accepted defaults for healthy adults. We don't let you set per-macro grams in v1 to keep the math one-way: edit your inputs, see your numbers update.

When your goals change.

Edits to your Profile take effect starting tomorrow at midnight in your local timezone. Today's plan is sealed from the moment the day begins. Your calorie target doesn't shift mid-day when you make a change.

Past days keep the target you were under at the time. You can swipe back to any prior day and see how you did against that day's goal, not today's. Editing your profile updates today and forward only; it never rewrites history.

The one exception is your very first profile during onboarding, which applies right away. You're starting from nothing, there's no plan to seal.

Correcting a wrong weight.

On the Progress tab, tap any dot on the weight chart to delete that entry. Useful if you typed the wrong number. Deleting a dot removes it from the chart only.

If the deleted weight was the latest one you logged, your future plan corrects itself automatically the next time you log a weight. But past daily targets stay as they were. You were aiming at that number on that day, even if the input was wrong. We don't rewrite history; we let you fix what's still in motion.

Calibration over time.

Coming soon. The Mifflin-St Jeor formula is a strong starting point, but real metabolism varies. After ~4 weeks of weight and meal data, Sufra will compare your projected vs. actual progress and suggest an updated maintenance number if the two have drifted apart. This calibration will always require your confirmation. We never silently move your target.

References.

1. Mifflin, M.D. et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition, 51(2), 241–247.
2. Wishnofsky, M. (1958). Caloric equivalents of gained or lost weight. American Journal of Clinical Nutrition, 6(5), 542–546. The 7,700 kcal/kg figure is a widely-used approximation and is known to be more accurate as a rule-of-thumb than an exact constant.
3. Institute of Medicine (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press.

For specific goals or medical conditions, talk to a registered dietitian. Sufra makes choices legible; it doesn't make recommendations.