How many calories should you eat a day?

“How many calories should I eat?” is really three questions stacked together: how much do you burn (maintenance), what's your goal (lose, maintain, gain), and what adjustment gets you there sustainably? Here's each one, without the fitness-influencer fog.

Step 1: estimate your maintenance calories

Maintenance = what your body burns in a normal day. The standard way to estimate it is a two-part calculation:

• Basal metabolic rate (BMR) — what you'd burn doing nothing. The widely used Mifflin-St Jeor formula:
  • Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
  • Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
• Activity multiplier — sedentary ≈ ×1.2, lightly active ≈ ×1.375, moderately active ≈ ×1.55, very active ≈ ×1.7 or more.

Example: a 30-year-old woman, 165 cm, 70 kg, lightly active → BMR ≈ 1,442 kcal → maintenance ≈ 1,980 kcal a day. A 35-year-old man, 180 cm, 85 kg, moderately active → BMR ≈ 1,805 kcal → maintenance ≈ 2,800 kcal. Same species, 800 kcal apart — which is why copying someone else's target rarely works.

Step 2: adjust for your goal

• Lose weight: eat below maintenance — a moderate deficit of ~300–500 kcal/day typically produces around 0.25–0.5 kg (0.5–1 lb) per week. Deeper isn't better if you can't sustain it; see what is a calorie deficit.
• Maintain: eat at maintenance and watch the monthly trend rather than daily wobble.
• Gain (muscle): a small surplus of ~200–300 kcal/day supports training without disproportionate fat gain.

Very low targets (under ~1,200 kcal/day) shouldn't be attempted without guidance from a healthcare professional.

Step 3: let reality vote

Formulas produce a starting estimate with an error bar — metabolism, NEAT (fidgeting, walking, life) and logging style all vary. The fix is simple: run your number for two or three weeks, log honestly, and watch the weight trend. Losing faster than planned? Add a little. Not moving? Trim 100–200 kcal or add steps. The trend is the truth; the formula was just the opening bid.

Get your number in SnapFood — then actually hit it

1. Answer a few questions. During onboarding, SnapFood asks about your body, activity and goal — lose, maintain or gain.
2. Get your targets. You receive a daily calorie budget plus protein, carb and fat targets built for you. Not generic numbers — yours.
3. Count down by camera. Every scanned meal subtracts from the day's budget: “1,160 of 2,000 kcal · 840 left” at a glance.
4. Watch the two panels. “Get enough” (protein, fiber…) and “Keep in check” (added sugar, sodium…) keep quality visible, not just quantity.
5. Track the trend. Log your weight in Progress; the trend chart and goal forecast show whether your target needs a nudge.

Frequently asked questions

Nutrition values, grades and recommendations in SnapFood are AI-generated estimates and may be inaccurate. This guide is general information, not medical or dietary advice. Calorie needs vary by individual — consult a qualified healthcare professional before making health or diet decisions.