How Many Calories Should I Eat to Lose Weight?

If you want to lose weight, the single most important number to know is how many calories you should eat per day. Get that number right and weight loss becomes a predictable, manageable process. Get it wrong — eating too little or guessing randomly — and you risk muscle loss, energy crashes, and results that stall within weeks.

This guide walks through the science-backed formula for calculating your personal calorie target, explains how to set a calorie deficit that actually works, and shows you exactly what to expect in terms of weekly fat loss.

Step 1 — Calculate Your TDEE (Total Daily Energy Expenditure)

Your TDEE is the total number of calories your body burns each day — from basic biological functions, movement, exercise, and digestion. Eating at or below this number determines whether you lose, maintain, or gain weight.

The most accurate widely available formula is the Mifflin-St Jeor equation, which research consistently shows outperforms the older Harris-Benedict formula for most adults.

Step 1a — Calculate your Basal Metabolic Rate (BMR):

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

BMR represents the calories your body needs at complete rest — just to keep your organs functioning, maintain body temperature, and support cellular activity. A 35-year-old woman who is 165 cm tall and weighs 75 kg has a BMR of approximately 1,521 calories.

Step 1b — Multiply by your activity factor:

• Sedentary (desk job, little exercise) — BMR × 1.2
• Lightly active (light exercise 1–3 days/week) — BMR × 1.375
• Moderately active (moderate exercise 3–5 days/week) — BMR × 1.55
• Very active (hard exercise 6–7 days/week) — BMR × 1.725
• Extremely active (physical job + daily training) — BMR × 1.9

That same woman with a lightly active lifestyle has a TDEE of 1,521 × 1.375 ≈ 2,092 calories. This is her maintenance level — the amount she needs to eat to stay exactly at her current weight.

Step 2 — Set Your Calorie Deficit

A calorie deficit means consuming fewer calories than your TDEE. This forces your body to draw on stored energy (body fat) to make up the difference. The size of your deficit directly controls both your rate of fat loss and how sustainable the diet is over time.

Here are the three main deficit approaches:

• Mild deficit (250–300 cal/day below TDEE): Produces about 0.5 lb of fat loss per week. Extremely sustainable, low hunger, best for people who are close to their goal weight or are new to tracking calories.
• Moderate deficit (500 cal/day below TDEE): Produces about 1 lb of fat loss per week. The standard recommendation for most people. Sustainable for several months with proper protein intake.
• Aggressive deficit (750–1,000 cal/day below TDEE): Produces 1.5–2 lb of fat loss per week. Appropriate for people who are significantly overweight under medical supervision. Higher risk of muscle loss and diet fatigue without very high protein intake.

Most research recommends staying within a 500–750 calorie daily deficit for most healthy adults. Going below 1,200 calories/day (women) or 1,500 calories/day (men) is generally not recommended without medical supervision, as it makes it very difficult to meet micronutrient needs.

A Complete Worked Example

Let us walk through a full calculation using a real example. Suppose you are a 32-year-old woman, 5'6" (168 cm), currently weighing 165 lbs (75 kg), with a moderately active lifestyle. Your goal is to lose 1 lb per week.

Calculate BMR:
BMR = (10 × 75) + (6.25 × 168) − (5 × 32) − 161 = 750 + 1,050 − 160 − 161 = 1,479 calories

Calculate TDEE:
Moderately active: 1,479 × 1.55 = 2,292 calories/day

Set your target:
2,292 − 500 = 1,792 calories/day to lose approximately 1 lb per week

So for this person, eating 1,792 calories per day — combined with a moderate activity level — should produce roughly 1 lb of fat loss per week, or about 4 lbs per month.

Step 3 — Set Your Protein and Macros

Total calories drive weight loss, but your macronutrient breakdown determines whether you lose fat, or fat and muscle. Protein is the most important macro to track on a deficit.

Protein target: Aim for 0.7–1.0 grams of protein per pound of body weight per day (1.5–2.2 g/kg). For our 165 lb example: 115–165 grams of protein daily. Higher protein intake during a deficit has consistently been shown to preserve lean muscle mass, reduce hunger, and improve body composition outcomes.

Carbohydrates and fat: Fill the remaining calories with a mix of carbohydrates and fats based on your preferences and what keeps you satiated. A common starting split is 40% carbs / 30% protein / 30% fat, but any ratio works as long as calories and protein targets are met.

High-Protein Foods: Calories vs. Protein

Hitting your protein target is easier when you know the calorie-to-protein ratio of common foods. These high-protein options give you the most protein per calorie:

Source: USDA FoodData Central. Values are approximate and vary by brand and preparation method.

What Rate of Weight Loss Should You Expect?

One pound of fat equals approximately 3,500 calories. This means:

Based on 3,500 calories = ~1 lb of fat (NIH estimate). Individual results vary based on body composition, hormones, and metabolic adaptation.

In practice, the first week or two often shows faster weight loss due to water weight reduction (particularly if you reduce carbohydrates or processed foods). After that, progress typically settles into the mathematically expected rate.

Weight loss is also not perfectly linear. Week-to-week fluctuations of 1–3 lbs are normal and caused by water retention, hormonal changes, food volume in the digestive system, and sodium intake. Track a 4-week average, not day-to-day numbers, for a true picture of your progress.

Common Calorie Counting Mistakes

Even people who track calories carefully often underestimate their intake. Research shows people consistently underestimate calorie consumption by 20–40%. Here are the most common errors:

• Not weighing food: Portion size estimates are notoriously inaccurate. A “medium banana” can range from 72 to 135 calories. Using a kitchen scale for high-calorie foods like nuts, oils, cheese, and meat eliminates the largest source of error.
• Forgetting cooking oils: A single tablespoon of olive oil is 120 calories. If you cook with oil and don't log it, you can easily add 300–500 untracked calories daily.
• Liquid calories: Juice, alcohol, lattes, and sports drinks add up fast. A 16 oz latte with whole milk is ~200 calories; a glass of wine is ~120–150 calories each.
• Overestimating exercise burn: Fitness trackers and cardio machines typically overestimate calories burned by 20–40%. Use exercise to improve fitness and health, not as a license to eat more.
• Not adjusting as you lose weight: As your body weight decreases, your TDEE decreases too. Recalculate every 10–15 lbs lost to avoid a stalled plateau.

How to Use Your Calorie Number

Once you know your target, the practical approach is straightforward: track your intake using a food diary app (Cronometer, MyFitnessPal, or similar), hit your protein target first, and fill the rest with whole foods that keep you satisfied.

You do not need to be perfect every day. A 7-day average that hits your calorie target is more important than hitting it exactly on any single day. If you go over by 300 calories on Saturday, a mild reduction on Sunday balances it without the need for drastic measures.

Alongside your calorie target, monitoring your BMI over time gives you a broader picture of how your weight loss is progressing relative to your height. Use it as one of several markers alongside body measurements and energy levels.

Frequently Asked Questions

How many calories should I eat per day to lose weight?

Most people lose weight on 1,200–1,800 calories per day depending on their size, age, sex, and activity level. The right number is your TDEE minus 500 calories for approximately 1 lb of fat loss per week. Use the calorie deficit calculator to get your personalized number.

What is the minimum calories I should eat to lose weight safely?

Most health authorities recommend a minimum of 1,200 calories/day for women and 1,500 calories/day for men when trying to lose weight. Going below these levels makes it very difficult to meet protein, vitamin, and mineral requirements and increases the risk of muscle loss and metabolic slowdown.

Why have I stopped losing weight despite eating at a deficit?

Weight loss plateaus happen for several reasons: your TDEE decreases as you lose weight (requiring a recalculation), water retention masking fat loss temporarily, measurement errors creeping into food tracking over time, or hormonal adaptations from a prolonged deficit. Recalculate your TDEE based on your current weight and temporarily increase protein intake to break through stalls.

Do I need to count macros to lose weight?

No — total calorie intake is the primary driver of weight loss. However, tracking protein intake (0.7–1g per pound of body weight) is highly beneficial for preserving muscle mass during a deficit. Full macro tracking is optional but useful if body composition (not just scale weight) matters to you.