How Many Calories Should You Eat? The Complete TDEE and Deficit Guide

Almost every fitness goal, losing fat, building muscle, or maintaining, comes down to one number most people never actually calculate: how many calories your body needs. Get this right and progress becomes predictable. Get it wrong and you spin your wheels for months. This guide shows you how to find your number and use it.

What Is TDEE?

TDEE stands for Total Daily Energy Expenditure, the total calories your body burns in a day. It is made up of four parts:

• BMR (Basal Metabolic Rate): Calories to keep you alive at rest, breathing, heartbeat, organs. This is the biggest chunk, around 60-70%.
• NEAT (Non-Exercise Activity Thermogenesis): Everything you do that is not formal exercise, walking, fidgeting, chores. Hugely variable and often underrated.
• TEF (Thermic Effect of Food): Calories burned digesting food, about 10%. Protein has the highest.
• EAT (Exercise Activity): Your actual workouts, often smaller than people assume.

Add these up and you get TDEE, your maintenance calories: eat that amount and your weight stays stable.

How to Estimate Your Calories

You can use an online calculator, but here is the logic. First estimate BMR (the Mifflin-St Jeor equation is the standard), then multiply by an activity factor:

• Sedentary (little exercise): BMR x 1.2
• Lightly active (1-3 days/week): BMR x 1.375
• Moderately active (3-5 days/week): BMR x 1.55
• Very active (6-7 days/week): BMR x 1.725

For example, a 70 kg, 30-year-old moderately active man has a BMR around 1,650 and a TDEE near 2,550. These numbers are estimates, treat them as a starting point and adjust based on real results over 2 to 3 weeks.

Calories for Fat Loss (a Deficit)

To lose fat, eat fewer calories than you burn. A deficit of about 300 to 500 calories per day below your TDEE is the sweet spot for most people, producing roughly 0.25 to 0.5 kg of fat loss per week. Aim to lose about 0.5 to 1% of your body weight weekly. Bigger deficits are tempting but cost muscle, tank energy, and rarely last. Slow and steady wins.

Calories for Muscle Gain (a Surplus)

To build muscle optimally, eat a small surplus, around 5 to 10% above TDEE (roughly 200 to 300 extra calories). This provides the energy to build tissue without piling on fat. Beginners can gain about 0.25 to 0.5 kg per month; gaining faster mostly adds fat you will later have to lose.

Protein and Macros Basics

Calories decide weight; macros (and training) decide whether you look toned or soft. The most important macro is protein:

• Protein: ~1.6 to 2.2 g/kg body weight. Preserves muscle in a deficit and builds it in a surplus.
• Fat: ~0.6 to 1 g/kg for hormones and health.
• Carbs: Fill the rest; they fuel training and recovery.

How to Track Accurately

The biggest reason people think "calories do not work for me" is inaccurate tracking. To get real data:

• Use a food app (like a calorie tracker) for a few weeks to learn portions.
• Weigh foods where you can; eyeballing is often off by hundreds of calories.
• Count everything: oils, sauces, drinks, and "bites" add up fast.
• Be consistent, not perfect: tracking most days accurately beats occasional perfection.

Adjusting Over Time

Your calculated number is a starting estimate, your body is the real calculator. Track your weight trend (a weekly average, not daily) for 2 to 3 weeks:

• Losing too fast or feeling awful? Add 100 to 200 calories.
• Not losing after 2 to 3 weeks? Reduce by 100 to 200, or add daily steps.
• Stalled while dieting long-term? Metabolism adapts; a short maintenance "diet break" of 1 to 2 weeks can help.

NEAT often drops when you diet (you move less unconsciously), which is why increasing daily steps is such a reliable lever.

Common Mistakes To Avoid

• Guessing instead of measuring: Portion estimates are usually wildly off.
• Too aggressive a deficit: Crash diets lose muscle and rebound.
• Ignoring protein: Hitting calories but missing protein wrecks body composition.
• Forgetting liquid calories: Juices, lattes, and alcohol are easy to overlook.
• Never adjusting: The starting number is an estimate; adapt it to real results.
• Weekend blowouts: Two loose days can erase five disciplined ones.

Realistic Timeline

Fat loss of 0.5 to 1% of body weight per week is sustainable and protects muscle. That means a realistic 2 to 4 kg per month for many people, faster at higher body weights, slower as you lean out. Consistency over months, not intensity over days, is what delivers results.

What To Do This Week

1. Estimate your TDEE with a calculator or the method above.
2. Set your target: TDEE minus 300-500 for fat loss, or plus 200-300 for muscle.
3. Set a protein goal (body weight in kg x 1.8) and track for one week.
4. Weigh yourself a few times and use the weekly average to adjust.

FAQ

How many calories should I eat to lose weight?

Roughly 300 to 500 calories below your TDEE (maintenance) per day, which produces about 0.25 to 0.5 kg of fat loss weekly for most people. Adjust based on 2 to 3 weeks of real results.

What is TDEE?

Total Daily Energy Expenditure, the total calories you burn in a day from your resting metabolism, daily movement, digestion, and exercise. Eating at your TDEE maintains weight.

Are calorie calculators accurate?

They give a good starting estimate, usually within 10%. Your real needs are confirmed by tracking your weight trend over a few weeks and adjusting.

Do I have to count calories forever?

No. Counting for a few weeks teaches you portions and awareness. Many people then maintain results with those habits without tracking every day.

Why am I not losing weight in a deficit?

Usually inaccurate tracking, underestimated portions, or reduced daily movement (NEAT). Tighten tracking, count liquids and oils, and add steps before cutting calories further.

How FitLifestyle Helps

FitLifestyle sets your calories and macros to your exact goal and adjusts them as your body changes, so you stop guessing and eat the right amount to lose fat or build muscle with confidence.