How Many Calories Should I Eat to Lose Weight?

The Short Answer on How Many Calories Should I Eat to Lose Weight

If you’re asking how many calories should I eat to lose weight, here’s the direct answer: most people need to eat 500 fewer calories per day than they burn to lose about one pound per week. That’s it. That’s the core math. But the actual number you land on depends on your age, sex, height, weight, and how much you move around during the day. A 5’4″ woman who sits at a desk job has very different needs than a 6’1″ man who works in construction. So while 1,500 calories might work perfectly for one person, it could leave another person dizzy and unable to function.

The reason this question matters so much is because getting the number wrong — in either direction — leads to failure. Eat too little and your metabolism fights back. Eat too much and nothing changes on the scale. This article walks through the actual science, gives you formulas you can use today, and covers the mistakes that trip people up most often.

How Many Calories to Lose Weight: Understanding Your Baseline

Before you can figure out how many calories to lose weight, you need to know your Total Daily Energy Expenditure, or TDEE. That’s the total number of calories your body burns in a full day, including everything from breathing to walking to digesting food.

TDEE is made up of three parts:

Basal Metabolic Rate (BMR) — the calories your body burns just to keep you alive. This accounts for roughly 60–70% of your total burn. Your heart beating, lungs expanding, cells repairing — all of that costs energy.

Thermic Effect of Food (TEF) — the energy your body uses to digest what you eat. This is about 10% of your total intake. Protein costs the most to digest, which is one reason high-protein diets help with fat loss.

Activity Thermogenesis — this covers both structured exercise and non-exercise movement like fidgeting, walking to the kitchen, or standing at your desk. This part varies wildly between people. Some people burn 200 extra calories a day from movement. Others burn 800.

How to Calculate Your BMR

The most commonly used formula is the Mifflin-St Jeor equation. Research published in the Journal of the American Dietetic Association found it to be the most accurate for estimating BMR in both normal-weight and overweight individuals.

For men: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5

For women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161

Let me walk through a real example. Say you’re a 35-year-old woman, 5’6″ (167.6 cm), and 170 pounds (77.1 kg). Your BMR would be: (10 × 77.1) + (6.25 × 167.6) – (5 × 35) – 161 = 771 + 1047.5 – 175 – 161 = 1,482.5 calories per day.

That’s just for existing. You then multiply by an activity factor:

Sedentary (desk job, little exercise): BMR × 1.2
Lightly active (exercise 1–3 days/week): BMR × 1.375
Moderately active (exercise 3–5 days/week): BMR × 1.55
Very active (hard exercise 6–7 days/week): BMR × 1.725

Using the same example with a lightly active lifestyle: 1,482.5 × 1.375 = roughly 2,038 calories per day as her TDEE. To lose one pound per week, she’d aim for about 1,538 calories daily.

The Calorie Deficit: Where Fat Loss Actually Happens

A calorie deficit means you consume fewer calories than your body uses. One pound of body fat contains approximately 3,500 calories. So to lose one pound per week, you need a total weekly deficit of 3,500 calories, which breaks down to 500 per day.

That 3,500-calorie rule has been around since the 1950s. Researchers like Dr. Kevin Hall at the National Institutes of Health have pointed out it’s a simplification — your body adapts as you lose weight, so the math shifts over time. But as a starting point, it works well enough for most people.

You can create that deficit three ways:

Eat less. Move more. Or do both.

Doing both tends to produce the best results. A 2014 meta-analysis in the journal Obesity Reviews found that combining diet and exercise led to 20% greater weight loss than diet alone over a 12-month period.

How Big Should Your Deficit Be?

This is where people mess up. They get impatient and slash calories way too aggressively. A 1,000-calorie-per-day deficit will technically produce two pounds of loss per week. But it also tanks your energy, increases muscle loss, disrupts hormones, and usually leads to binge eating within a few weeks.

The National Institute of Diabetes and Digestive and Kidney Diseases recommends a rate of 1–2 pounds per week for sustainable weight loss. Most registered dietitians recommend sticking closer to one pound per week for people who don’t have a large amount of weight to lose.

If you have 100+ pounds to lose, a larger deficit — say 750–1,000 calories — can be appropriate under medical supervision. But if you’re trying to lose 15–30 pounds, a 500-calorie deficit is the sweet spot.

Calories to Lose Weight: Real Numbers for Real People

Let me lay out some realistic calorie targets based on common body types and activity levels. These aren’t prescriptions. They’re examples to give you a ballpark.

Example 1: Sedentary Office Worker

Male, 40 years old, 5’10”, 210 lbs. BMR is approximately 1,870. TDEE at sedentary (×1.2) is about 2,244. A 500-calorie deficit puts his target at roughly 1,744 calories per day. At that intake, he’d lose close to one pound per week without adding any exercise.

Example 2: Active Young Woman

Female, 28 years old, 5’5″, 155 lbs. BMR is roughly 1,430. She does CrossFit four times a week, so her TDEE at moderately active (×1.55) is around 2,217. With a 500-calorie deficit, she’d eat about 1,717 calories daily. That’s enough to fuel her workouts while still losing fat steadily.

Example 3: Older Adult Getting Started

Female, 58 years old, 5’3″, 185 lbs. BMR is about 1,370. Lightly active with daily walks. TDEE at ×1.375 is approximately 1,884. A 500-calorie deficit would put her at 1,384. That’s tight. In her case, a smaller deficit of 300–400 calories might work better to avoid fatigue and preserve bone density. She could aim for 1,500 calories and add slightly longer walks to make up the difference.

These examples show why asking how many calories should I eat to lose weight doesn’t have a single answer. The number is personal.

Minimum Calorie Thresholds You Should Know About

The American College of Sports Medicine and most major health organizations recommend that women don’t eat below 1,200 calories per day and men don’t go below 1,500 unless supervised by a doctor. These aren’t arbitrary limits.

Below those thresholds, it becomes extremely difficult to get adequate vitamins, minerals, and macronutrients. Your body starts pulling from muscle tissue for energy. Thyroid function can slow down. For women, menstrual cycles can become irregular or stop entirely — a condition called hypothalamic amenorrhea that signals your body is under too much stress.

I’ll share something here. A friend of mine — let’s call her Sarah — went on a 900-calorie diet she found online back in 2022. She lost 12 pounds in three weeks. She also lost clumps of hair, her period disappeared for four months, and she gained all 12 pounds back plus five more within two months of stopping. Her doctor told her the severe restriction had likely slowed her resting metabolic rate by 15–20%, which made regaining the weight almost inevitable once she returned to normal eating.

That story isn’t unusual. Research from the long-term follow-up of “The Biggest Loser” contestants, published in the journal Obesity in 2016, found that severe calorie restriction led to metabolic adaptation that persisted for at least six years after the show ended. Their bodies burned 500 fewer calories per day than expected for their size.

What Should You Actually Eat Within Those Calories?

Knowing the calories to lose weight is step one. But what you fill those calories with matters enormously for hunger, energy, muscle retention, and long-term success.

Protein Comes First

Aim for 0.7–1.0 grams of protein per pound of body weight daily. A 2018 systematic review in the British Journal of Sports Medicine found that higher protein intake during a calorie deficit preserved significantly more lean mass compared to lower protein diets. Protein also has the highest satiety rating of any macronutrient — it keeps you full longer.

For a 160-pound person, that means 112–160 grams of protein per day. Chicken breast, eggs, Greek yogurt, cottage cheese, lean beef, fish, tofu, and protein powder are all practical sources.

Fat Shouldn’t Be Feared

Dietary fat is essential for hormone production, brain function, and absorbing fat-soluble vitamins (A, D, E, K). Keep fat at roughly 25–35% of total calories. For someone eating 1,700 calories, that’s 47–66 grams of fat per day. Avocados, olive oil, nuts, seeds, and fatty fish are solid choices.

Carbs Fill the Rest

After setting protein and fat, carbohydrates make up whatever calories remain. Carbs fuel your workouts and your brain. Whole grains, fruit, vegetables, legumes, and potatoes are nutrient-dense carb sources that also provide fiber — which helps with fullness and gut health.

There’s no metabolic advantage to cutting carbs extremely low unless you have a specific medical condition like epilepsy or insulin resistance that responds to ketogenic diets. A 2020 meta-analysis in The BMJ found no significant difference in weight loss between low-carb and low-fat diets when calories and protein were matched.

Common Mistakes When Counting Calories to Lose Weight

Underestimating Portion Sizes

Research from the USDA found that people underestimate their calorie intake by an average of 40%. That’s not a typo. A study published in the Annals of Internal Medicine showed that even registered dietitians underestimated by about 200 calories per day. The rest of us are far worse.

Using a food scale — at least for the first few weeks — makes an enormous difference. A “tablespoon” of peanut butter eyeballed from a jar can easily be two or three tablespoons. That’s an extra 100–200 calories you didn’t account for.

Forgetting Liquid Calories

A large latte with whole milk is 200+ calories. A glass of orange juice is 110. Two beers on a Friday night add 300–400. These don’t register as “eating” in most people’s minds, but they absolutely count toward your total.

Weekend Overconsumption

You eat 1,600 calories Monday through Friday. Then Saturday and Sunday hit, and between brunch, snacks, and dinner out, you consume 2,800 each day. Your weekly average jumps to about 1,943 per day — which might completely erase your deficit.

This pattern is incredibly common and almost invisible unless you track consistently.

Using Exercise to “Earn” Extra Food

Calorie burn estimates from fitness trackers and gym machines are notoriously inaccurate. A Stanford study found that popular wrist-worn trackers overestimated calorie burn by 27–93%. If your treadmill says you burned 400 calories and you eat 400 extra calories, you may have actually only burned 250. Now you’re in a surplus.

How to Track Calories Without Losing Your Mind

You don’t have to track forever. But tracking for 2–4 weeks teaches you what portions actually look like, which foods are calorie-dense, and where your blind spots are.

Apps like MyFitnessPal, Cronometer, and MacroFactor make it easier. Cronometer is generally considered the most accurate because it uses verified USDA food data rather than user-submitted entries. MacroFactor adjusts your targets based on your actual weight trends over time, which accounts for metabolic adaptation automatically.

After a few weeks, most people develop enough awareness to estimate portions reasonably well without logging every bite. The goal isn’t to become obsessive. The goal is to build awareness so you can make better decisions on autopilot.

If tracking feels triggering or leads to anxiety around food, skip it. Use hand-sized portion methods instead: a palm-sized portion of protein, a fist of carbs, a thumb of fat, and a fist of vegetables at each meal. This approach, popularized by Precision Nutrition, has been shown to produce results comparable to calorie counting in large coaching studies.

How Long Does It Take to See Results?

With a consistent 500-calorie daily deficit, expect to lose about 4 pounds in the first month. The first week may show a larger drop — sometimes 3–5 pounds — but most of that is water, not fat. Reducing carb intake causes your body to release stored glycogen, and each gram of glycogen holds about 3 grams of water.

After the initial water drop, 0.5–1.5 pounds per week is normal and healthy. If you’re not losing at that rate after 3–4 weeks of consistent tracking, one of three things is happening:

You’re eating more than you think. You’re burning less than you think. Or both.

It’s almost never a “broken metabolism.” A 2020 study in Science found that metabolic rates vary far less between individuals of the same size and age than previously believed. The variation is typically 100–200 calories at most. The real culprit is almost always inaccurate tracking.

Adjusting Your Calories Over Time

Your calorie needs decrease as you lose weight. A body that weighs 180 pounds burns fewer calories at rest than one that weighs 200 pounds. So the deficit that worked at the start may stop producing results after 10–15 pounds of loss.

Recalculate your TDEE every 10–15 pounds. Or use an app like MacroFactor that adjusts automatically based on your weight trend data.

There’s also a concept called adaptive thermogenesis — your body becomes slightly more efficient when it’s been in a deficit for a long time. Non-exercise movement tends to decrease. You fidget less. You take fewer steps without realizing it. Research from Dr. James Levine at the Mayo Clinic found that NEAT (non-exercise activity thermogenesis) can decrease by 200–300 calories per day during prolonged dieting.

This is why diet breaks work. Spending 1–2 weeks eating at maintenance calories every 8–12 weeks of dieting can help restore metabolic rate, reduce hunger hormones, and improve long-term adherence. A 2018 study in the International Journal of Obesity found that participants who took diet breaks lost more fat and kept it off longer than those who dieted continuously.

Should You Use a Very Low Calorie Diet?

Very low calorie diets (VLCDs) involve eating 800 calories or fewer per day. They exist in clinical settings for patients with BMIs above 30 who need rapid weight loss before surgery or for severe health reasons. They use specially formulated meal replacements to meet micronutrient needs.

VLCDs are not appropriate for general use. The muscle loss, metabolic slowdown, gallstone risk, and psychological effects make them a poor choice for anyone without close medical monitoring. A 2019 review in Obesity Surgery found that while VLCDs produce fast initial results, long-term outcomes at five years were no better than moderate calorie restriction.

Slow and steady isn’t glamorous. But the data consistently shows it wins.

Putting It All Together

Figuring out how many calories should I eat to lose weight comes down to a handful of steps. Calculate your BMR using the Mifflin-St Jeor equation. Multiply by your activity factor to get your TDEE. Subtract 500 calories for a sustainable one-pound-per-week rate of loss. Prioritize protein at 0.7–1.0 grams per pound of body weight. Track your intake for a few weeks to build awareness. Weigh yourself regularly and adjust your targets as your body changes.

None of this requires special foods, expensive supplements, or extreme restriction. The fundamentals haven’t changed. Eat fewer calories to lose weight than your body burns, get enough protein, and stay consistent over months — not days.

Read the rest of our articles and more useful info down below for deeper dives into how many calories to lose weight based on your specific situation, meal planning strategies, exercise programming, and more. Whatever your starting point, the math works if you give it time.