How Many Calories Should I Eat to Lose Weight?
The answer depends on your body, your activity level, and how quickly you want to lose weight. There is no single number that works for everyone. But the underlying math is straightforward, and once you understand how energy balance works, you can find a calorie target that leads to steady, sustainable fat loss without crashing your metabolism or losing muscle.
Understanding Calories and Energy Balance
A calorie is a unit of energy. Your body needs energy to keep your heart beating, your lungs breathing, your brain functioning, and your muscles moving. You get that energy from the food and drinks you consume. When you take in more energy than your body uses, the excess gets stored, primarily as body fat. When you take in less energy than your body uses, it pulls from those stored reserves. This is the principle of energy balance.
Weight loss, at its most fundamental level, requires a negative energy balance, commonly called a calorie deficit. You need to consume fewer calories than your body expends. This is not a theory or a diet trend. It is a basic law of thermodynamics that applies regardless of whether you eat low-carb, low-fat, paleo, keto, or any other dietary pattern. The composition of your diet matters for health, satiety, and body composition, but the calorie deficit is what drives fat loss.
The practical question, then, is: how many calories does your body actually use in a day? That number is your Total Daily Energy Expenditure.
What Is TDEE (Total Daily Energy Expenditure)?
Your Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns in a 24-hour period. It is made up of several components:
- Basal Metabolic Rate (BMR) — The calories your body burns at complete rest just to maintain vital functions like breathing, circulation, and cell repair. This accounts for roughly 60-70% of total expenditure for most people.
- Thermic Effect of Food (TEF) — The energy used to digest, absorb, and process the food you eat. This typically accounts for about 10% of total calories consumed. Protein has the highest thermic effect, followed by carbohydrates, then fats.
- Physical Activity — The calories burned through deliberate exercise (running, weight training, swimming) and non-exercise activity thermogenesis (NEAT), which includes walking, fidgeting, standing, and all other daily movements. This is the most variable component and can range from 15% to 30% or more of your TDEE.
Your TDEE is the number you need to know before you can set a calorie target for weight loss. Eat below your TDEE, and you lose weight. Eat above it, and you gain weight. Eat at your TDEE, and your weight stays roughly the same.
How to Calculate Your TDEE
The most widely used and research-validated method for estimating TDEE starts with calculating your Basal Metabolic Rate using the Mifflin-St Jeor equation, then multiplying by an activity factor. The Mifflin-St Jeor equation, published in 1990, has been shown in multiple studies to be the most accurate predictive BMR formula for most adults.
The Mifflin-St Jeor Equation
For men: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5
For women: BMR = (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161
Activity Multipliers
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Desk job, little or no exercise | 1.2 |
| Lightly active | Light exercise 1-3 days/week | 1.375 |
| Moderately active | Moderate exercise 3-5 days/week | 1.55 |
| Very active | Hard exercise 6-7 days/week | 1.725 |
| Extremely active | Very hard exercise, physical job | 1.9 |
Worked Example
Let's calculate the TDEE for a 30-year-old male who weighs 180 pounds, stands 5'10" tall, and is moderately active (exercises 3-5 days per week).
Step 1: Convert to metric units.
- Weight: 180 lbs / 2.205 = 81.6 kg
- Height: 5'10" = 70 inches x 2.54 = 177.8 cm
Step 2: Calculate BMR using the Mifflin-St Jeor equation.
BMR = (10 x 81.6) + (6.25 x 177.8) - (5 x 30) + 5
BMR = 816 + 1,111.25 - 150 + 5 = 1,782 calories/day
Step 3: Multiply by the activity factor.
TDEE = 1,782 x 1.55 (moderately active) = 2,762 calories/day
This means our example person burns approximately 2,762 calories per day. To lose weight, he needs to eat fewer than 2,762 calories consistently. You can use our calorie calculator to run these numbers for your own stats without doing the math by hand.
The Calorie Deficit for Weight Loss
A widely cited rule of thumb is that a deficit of approximately 3,500 calories results in the loss of about one pound of body fat. While recent research suggests this relationship is not perfectly linear over long periods due to metabolic adaptation, it remains a useful starting framework for planning your deficit.
Using our example above (TDEE of 2,762 calories), here is what different deficit levels would look like:
| Daily Deficit | Weekly Deficit | Expected Weight Loss | Daily Calorie Target |
|---|---|---|---|
| 250 calories | 1,750 calories | ~0.5 lb/week | 2,512 calories |
| 500 calories | 3,500 calories | ~1 lb/week | 2,262 calories |
| 750 calories | 5,250 calories | ~1.5 lb/week | 2,012 calories |
| 1,000 calories | 7,000 calories | ~2 lb/week | 1,762 calories |
For most people, a deficit of 500 calories per day, producing roughly one pound of weight loss per week, is a sustainable and effective target. A smaller deficit of 250 calories per day is appropriate for those who have less weight to lose or who want a more gradual approach. Deficits greater than 750 to 1,000 calories per day are generally not recommended without medical supervision because they increase the risk of muscle loss, nutrient deficiencies, and metabolic slowdown.
Minimum Calorie Intakes
Regardless of how quickly you want to lose weight, there are floors below which you should not drop your calorie intake. The commonly referenced general guidelines are:
- Women: No fewer than 1,200 calories per day
- Men: No fewer than 1,500 calories per day
These thresholds exist because eating below them makes it extremely difficult to get adequate vitamins, minerals, and other essential nutrients from food alone. Very low-calorie diets (below 800 calories per day) do exist as medical interventions, but they require physician supervision, are typically short-term, and often use specially formulated meal replacements to prevent nutritional deficiencies.
If your calculated calorie target for weight loss falls below these minimums, you are better off increasing your activity level to widen the deficit rather than cutting food intake further. Adding a 30-minute walk burns roughly 150-200 calories, which creates a deficit without pushing your intake dangerously low.
Macronutrient Balance Matters
Calories determine whether you lose weight, but the breakdown of those calories into protein, carbohydrates, and fat, your macronutrient ratio, significantly affects what kind of weight you lose and how you feel while losing it.
Protein Is the Priority
When you eat in a calorie deficit, your body does not exclusively burn fat. It can also break down muscle tissue for energy, especially if protein intake is inadequate. Research consistently shows that higher protein intake during a deficit helps preserve lean muscle mass, keeps you feeling fuller for longer, and has a higher thermic effect (your body burns more calories digesting protein than carbs or fat).
A general target for people in a calorie deficit is 0.7 to 1.0 grams of protein per pound of body weight per day. For our 180-pound example, that means roughly 126 to 180 grams of protein daily. Good sources include lean meats, poultry, fish, eggs, dairy, legumes, and tofu.
Carbs and Fats
After hitting your protein target, the remaining calories can be split between carbohydrates and fats based on your preferences and what helps you stick to your plan. Neither carbs nor fats are inherently fattening. What matters is total calorie intake. Some people feel better and have more energy on a moderate-carb diet. Others prefer higher fat and lower carbs. The best split is the one that keeps you satisfied and consistent.
Common Mistakes That Stall Weight Loss
Understanding the math is the easy part. Consistently executing it is where most people struggle. Here are the most common mistakes that prevent people from reaching their goals:
Cutting Too Aggressively
It is tempting to slash calories dramatically for faster results. A 1,500-calorie deficit might sound like it will get you to your goal twice as fast, but the reality is different. Extreme deficits lead to significant muscle loss, hormonal disruption (particularly drops in thyroid hormones and testosterone), intense hunger, fatigue, and a higher likelihood of binge eating. People who crash diet almost always regain the weight, often ending up heavier than when they started. A moderate, sustainable deficit beats an aggressive one every time.
Not Counting Liquid Calories
Coffee drinks, smoothies, juice, soda, alcohol, and even seemingly healthy beverages like oat milk lattes can add hundreds of untracked calories per day. A large flavored latte can contain 300-400 calories. Two glasses of wine add another 250-300. These are easy to overlook because liquids do not trigger the same fullness signals as solid food. If your calorie counting does not include everything you drink, your actual intake may be significantly higher than you think.
Weekend Overeating
Eating in a 500-calorie deficit Monday through Friday creates a weekly deficit of 2,500 calories. But if Saturday and Sunday each involve eating 1,250 calories above maintenance (dinners out, brunch, snacking, drinks), that surplus of 2,500 calories wipes out the entire week's progress. You do not need to be perfect on weekends, but consistently undoing five days of discipline in two days is one of the most common and underrecognized reasons people plateau.
Ignoring Metabolic Adaptation
As you lose weight, your body requires fewer calories to maintain itself. A person who weighed 200 pounds and now weighs 170 pounds has a lower TDEE than when they started. If you keep eating the same number of calories that produced your initial deficit, that deficit shrinks over time. This is normal and expected. The solution is to recalculate your TDEE periodically, roughly every 10-15 pounds lost, and adjust your calorie target accordingly. Our TDEE calculator makes it easy to recheck your numbers as your body changes.
Practical Tips for a Sustainable Deficit
Knowing how many calories to eat is one thing. Actually doing it, day after day, is another. These strategies help make a calorie deficit feel less like a punishment and more like a manageable routine:
- Track your food for at least two weeks. You do not need to count calories forever, but tracking for a short period teaches you what portions actually look like and where your calories are coming from. Most people significantly underestimate their intake.
- Eat more protein and fiber. Both keep you full longer. A meal of grilled chicken, roasted vegetables, and a small portion of rice will keep you satisfied far longer than the same number of calories from a bagel with cream cheese.
- Do not drink your calories. Replace caloric beverages with water, black coffee, or unsweetened tea. This single change can eliminate 200-500 calories per day for many people.
- Plan for social eating. If you know you have a dinner out on Friday, eat lighter earlier in the day. You do not need to skip the dinner; you need a plan for fitting it into your weekly calorie budget.
- Lift weights. Resistance training preserves muscle mass during a deficit, keeps your metabolic rate higher, and improves body composition. Cardio burns calories, but weight training shapes the body underneath the fat. Ideally, do both.
- Sleep 7-9 hours. Poor sleep increases hunger hormones (ghrelin goes up, leptin goes down), reduces willpower, and makes your body more likely to store fat and burn muscle. Sleep is not a luxury when you are trying to lose weight. It is a requirement.
- Be patient and consistent. Weight fluctuates daily due to water retention, sodium intake, hormonal cycles, and digestive contents. Do not judge your progress by any single day on the scale. Track weekly averages over at least a month before deciding whether your calorie target needs adjusting.
The Bottom Line
To lose weight, you need to eat fewer calories than your body burns. Calculate your TDEE, subtract 250 to 500 calories for a moderate and sustainable deficit, prioritize protein to preserve muscle, and stay consistent. There is no magic food, supplement, or meal timing trick that overrides the calorie deficit. The best diet is the one you can follow long-term while meeting your nutritional needs.
Use a calorie calculator to find your starting number, a macro calculator to dial in your protein, carbs, and fats, and check your BMI as one of several metrics to track your progress. Recalculate every few weeks as your weight changes, adjust when progress stalls, and give the process time to work.
This information is for educational purposes. Consult a healthcare professional before starting any diet.