Fat loss comes down to one principle: over time, you take in a little less energy than you burn. That's a calorie deficit. Everything else — which diet, which foods, which app — is just a different way of getting there. Here's how to estimate your number in three steps, without a spreadsheet.
Step 1: Estimate what you burn
Your total daily energy expenditure (TDEE) is roughly what you burn in a day. A quick estimate: multiply your body weight in pounds by 14–16 if you're moderately active. So a 175 lb person burns roughly 2,450–2,800 calories a day. It's an estimate, not a law of physics — we'll adjust it with real data below.
Step 2: Subtract a gentle deficit
Take 300–500 calories off that number. For our example, that's a target of about 2,000–2,400 calories per day. That modest gap tends to produce around 0.5–1 lb of fat loss per week — slow enough to protect your energy and muscle, fast enough to see progress.
The best deficit isn't the biggest one. It's the biggest one you can hold for months without white-knuckling it.
Aggressive crash deficits backfire: hunger spikes, energy tanks, and the plan collapses the first hard week. The U.S. Centers for Disease Control notes that people who lose weight gradually and steadily are more successful at keeping it off.
Step 3: Prioritize protein and adjust
Within your calorie target, aim for a solid protein source at each meal (roughly 0.7–1 g per pound of goal body weight per day). Protein keeps you full and helps preserve muscle while you lose fat. Fill the rest of the plate with vegetables, some quality carbs around activity, and fats you enjoy.
Then let reality be your calculator:
- Losing 0.5–1 lb/week?You've got the right number. Keep going.
- No change after 2–3 weeks? Trim another ~150 calories, or add a daily walk.
- Losing fast but exhausted? Add 100–200 calories back. Energy is part of the plan, not a weakness.
The part most calculators miss
A calorie target is a starting guess. Your body, schedule, and appetite change week to week — a target that fit a calm week is wrong the week you travel or barely sleep. That's exactly what an adaptive fat-loss planis for: you check in, and next week's targets and meals adjust to what actually happened — instead of you failing a fixed number.
Want the math done for you and adjusted every week? Get your free 3-day plan — no calorie counting required.