Guide September 2026 · 8 min read

Step 1: Estimate your maintenance calories

Maintenance, or TDEE (total daily energy expenditure), is what you burn in a day at your current weight and activity. Every online calculator uses a version of the same two-step method.

First, resting metabolic rate (Mifflin-St Jeor equation):

• Men: (10 × weight kg) + (6.25 × height cm) − (5 × age) + 5
• Women: (10 × weight kg) + (6.25 × height cm) − (5 × age) − 161

Then multiply by an activity factor:

Example: a 35-year-old woman, 70 kg, 165 cm, lightly active. RMR = 700 + 1,031 − 175 − 161 = 1,395 kcal. TDEE = 1,395 × 1.375 ≈ 1,920 kcal.

Most people overestimate their activity factor. If unsure, pick the lower one.

Step 2: Choose the deficit

The old "3,500 kcal = 1 lb" rule is a simplification — the body adapts, so real loss slows over time — but it is close enough for setting a starting point.

A second way to size it: aim for 0.5–1% of body weight per week. At 70 kg that is 350–700 g. At 100 kg, 500 g–1 kg. Heavier people can run a slightly larger absolute deficit; lighter people should stay small.

For the example above: 1,920 − 450 ≈ 1,450–1,500 kcal a day.

Step 3: Set a floor

A deficit is not a race to the bottom. Below a certain intake it becomes hard to hit protein and fiber targets, energy drops, and the diet fails. Common floors:

• Women: not below ~1,200–1,300 kcal without medical supervision.
• Men: not below ~1,500 kcal.

If your calculated target lands below the floor, the fix is not to eat the floor and hope — it is to raise activity (walking adds 200–350 net kcal a day) so the same deficit sits at a higher intake.

Step 4: Make the deficit not feel like one

This is the part most calculators skip and the part that determines whether you are still doing this in March.

Protein: 1.6 g per kg. At 70 kg, 110 g a day, spread across three or four meals of 25–40 g. Protein is the most filling macronutrient per calorie and protects muscle in a deficit. Most people who "can't stick to a diet" are eating 60 g. How much protein per day →

Fiber: 25–30 g. Fiber is what makes 1,500 kcal feel like enough. Beans, oats, vegetables, fruit with skin, whole grains. Most people on a deficit cut fiber by accident because they cut carbs. How much fiber per day →

Sugar under 25 g, mostly from food not drinks. Sugary drinks are 200 kcal that do not register as food. Cutting them is often the entire deficit. Hidden sugar →

Volume. Vegetables, soups, salads, fruit — food that is mostly water and fiber fills the stomach for very few calories.

Meal structure. Three or four meals, each with protein and fiber, with the largest at whichever time you are usually hungriest. Skipping breakfast to "save calories" almost always produces a larger, worse dinner.

Sleep. Under six hours raises hunger hormones and carb cravings the next day. It is a nutrition variable.

Step 5: Measure, then adjust

The formula is an estimate with a margin of maybe ±15%. The real number comes from data:

1. Eat your target for two weeks and log everything — including oil, drinks and weekends.
2. Weigh daily, same time, same conditions, and use the weekly average. Daily weight swings 1–2 kg with water, salt and carbs; only the average means anything.
3. Compare. Losing 0.3–0.5 kg a week? The target is right. Losing nothing? Either the estimate was high or the logging is missing something — usually oil, sauces, drinks and weekend meals. Losing more than 1% a week and feeling drained? Add 150–200 kcal.
4. Recalculate every 5 kg lost. A lighter body burns less; the deficit shrinks unless you adjust.

When the scale stalls

A plateau is when the weekly average has not moved for three or more weeks. Common causes, in order:

• Logging drift. Portions creep, weekends go unlogged, "a splash" of oil becomes 200 kcal. Two honest weeks of logging fixes most plateaus.
• Water masking fat loss. High salt, a new exercise programme, or the week before a period can hold 1–2 kg of water over the fat you lost. Wait two weeks before changing anything.
• Adaptation. Metabolism does slow modestly in a long deficit — mostly because you weigh less and move less without noticing. Recalculate TDEE and add steps.
• The deficit is real but too small at the new body weight. Tighten by 100–150 kcal, or add activity.

What not to do: cut another 500 kcal. That is how a sustainable deficit turns into a crash diet.

Diet breaks and maintenance phases

After 8–12 weeks in a deficit, one to two weeks at maintenance calories is not a failure. It restores energy, appetite hormones and training performance, and it is the mental reset that keeps the next phase possible. The evidence on intermittent dieting (deficit blocks with maintenance breaks) shows equal or better fat loss with better adherence than continuous dieting.

What the tracker should do for you

Calculating the deficit takes five minutes. Holding it for four months is the work, and a tracker either helps with that or it does not. The useful ones do three things: make logging fast enough that weekends get logged, show the numbers that control hunger (protein, fiber, sugar) and not only calories, and tell you during the day what to adjust.

CalMePlease sets the target from your goal, logs meals from a photo, video, voice note or barcode, tracks ten metrics including the four that keep a deficit tolerable, and uses an AI coach to say "you're 40 g short on protein, here's dinner" at 15:00 rather than "over by 300" at midnight.

A worked plan

70 kg, 165 cm, 35-year-old woman, lightly active, goal −6 kg:

• TDEE ≈ 1,920 kcal. Target: 1,450–1,500 kcal.
• Protein: 110 g. Fiber: 25–30 g. Free sugar: <25 g. Salt: <5 g. Water: ~2 L.
• Steps: 8,000+.
• Weigh daily, judge weekly. Expect 0.4–0.5 kg/week, so roughly 12–15 weeks with a one-week maintenance break around week 8.
• Recalculate at 65 kg.

FAQ

How many calories should I eat to lose weight? Your maintenance (TDEE) minus 300–500 kcal. For most adults that lands between 1,400 and 2,200 kcal a day depending on size and activity. Do not go below ~1,200 (women) or ~1,500 (men) without medical guidance.

How do I calculate my calorie deficit? Estimate TDEE with the Mifflin-St Jeor equation and an activity factor, subtract 300–500 kcal, eat that for two weeks, and adjust based on the weekly average weight change.

Is a 500 calorie deficit enough? Yes. It produces about 0.5 kg a week and is the deficit most people can hold for months. Bigger is not better if it ends in week three.

Why am I not losing weight in a calorie deficit? Most often the deficit is smaller than you think — untracked oil, drinks and weekends — or water retention is hiding fat loss. Log honestly for two weeks and judge the weekly average.

Can I lose weight without counting calories? Some people can, by eating high-protein, high-fiber, low-sugar meals and stopping at 80% full. Tracking is not mandatory; it is the fastest way to find out why something is not working.

Should I eat back exercise calories? Not one-for-one. Trackers overestimate burn, and appetite rises with activity. Keep the food target fixed and treat activity as a bonus. How many calories do 10,000 steps burn →

---

This article is general information, not medical advice. If you have a medical condition, are pregnant, or have a history of disordered eating, work with a doctor or registered dietitian before starting a calorie deficit.

Related: How much protein per day · How much fiber per day · What is a good nutrition day?

CalMePlease sets your target from your goal and keeps protein, fiber, sugar and salt in view so the deficit holds. Free on the App Store.