How the plan is worked out
First the calculator estimates the calories you burn now (your TDEE) with the Mifflin-St Jeor equation and your activity level. A deficit of about 500 calories a day is the usual estimate for 1 lb (0.45 kg) of fat a week, so it takes that much off for each pound a week of your chosen pace.
Example: a 30-year-old man, 5 ft 9 in and 165 lb, lightly active, burns about 2,336 calories a day. To reach 150 lb at 1 lb a week he'd eat about 1,836 calories a day and get there in about 15 weeks.
Why the last pounds come off slower
As you lose weight you burn fewer calories, so the same intake gives a smaller deficit over time. The 500-calorie rule is a starting estimate; research models such as the NIH Body Weight Planner show progress slowing over months. Recalculate every 10 lb or so, and judge by your weight trend over two to three weeks rather than day to day.
Protein and strength training help keep muscle while you lose fat. To plan protein, carbs and fat, use the macro calculator. If you have a medical condition, are pregnant or have a history of disordered eating, work with a doctor or dietitian rather than a calculator.
Frequently asked questions
How fast can I safely lose weight?
About ½ to 2 lb a week for most adults, and ½ to 1 lb as you get closer to your goal. Faster loss tends to cost more muscle and is harder to keep off.
How many calories should I eat to lose 1 lb a week?
About 500 fewer than you burn each day. For many people that's somewhere between 1,500 and 2,200 calories, depending on size and activity.
Why am I not losing weight on schedule?
Water shifts can hide fat loss for a week or two, and calorie estimates are rarely exact. If the trend is flat for three or more weeks, cut about 100 to 200 calories a day or add activity.
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