How Many Calories Should I Eat to Lose Weight?

Most people lose weight consistently by eating 500 to 750 calories below their total daily energy expenditure (TDEE). For a moderately active adult, that usually lands somewhere between 1,500 and 2,200 calories per day. The exact number depends on your age, sex, height, current weight, and activity level. There is no single number that works for everyone.

A 500-calorie daily deficit produces roughly 1 pound of fat loss per week. A 750-calorie deficit pushes that closer to 1.5 pounds per week. The National Heart, Lung, and Blood Institute (NHLBI) recommends a rate of 1 to 2 pounds per week for safe, sustainable weight loss.

Start by estimating your TDEE. The most validated method is the Mifflin-St Jeor equation, which the Academy of Nutrition and Dietetics considers the most accurate predictive equation for estimating resting metabolic rate (RMR) in adults.

For men: (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) + 5. For women: (10 x weight in kg) + (6.25 x height in cm) - (5 x age in years) - 161. This gives you your RMR, the calories your body burns at complete rest.

Multiply your RMR by an activity factor: 1.2 for sedentary (desk job, minimal exercise), 1.375 for lightly active (light exercise 1 to 3 days per week), 1.55 for moderately active (moderate exercise 3 to 5 days per week), or 1.725 for very active (hard exercise 6 to 7 days per week). The result is your estimated TDEE.

Subtract 500 to 750 from your TDEE. That is your starting calorie target for weight loss.

You have probably seen blanket recommendations like "eat 1,200 calories" or "eat 1,500 calories." These numbers ignore individual variation. A 5'2" sedentary woman and a 6'1" active man have very different energy needs. Using the same target for both leads to either undereating or no results.

Going too low causes problems. Research published in the journal Obesity Reviews shows that very low calorie diets (below 1,000 to 1,200 calories) increase the risk of lean mass loss, nutrient deficiencies, and metabolic adaptation. They also tend to be harder to sustain, leading to cycles of restriction and overeating.

A good minimum floor: the Dietary Guidelines for Americans notes that calorie levels below 1,600 for men and 1,200 for women are difficult to meet nutrient needs with food alone. If your calculated target falls below these, work with a healthcare provider.

Body composition matters. Muscle tissue is more metabolically active than fat tissue. Two people at the same weight can have meaningfully different calorie needs based on their lean mass.

Age reduces energy needs. RMR declines roughly 1 to 2% per decade after age 20, primarily due to loss of lean mass. Staying physically active and maintaining muscle through resistance training slows this decline.

Non-exercise activity thermogenesis (NEAT) is a major variable that most people underestimate. NEAT includes all movement outside of formal exercise: walking, fidgeting, standing, cooking, cleaning. Research from the Mayo Clinic shows NEAT can vary by up to 2,000 calories per day between individuals. This is one reason two people on the same calorie plan can get very different results.

Sleep and stress also play a role. A study in the Annals of Internal Medicine found that sleep-restricted subjects lost 55% less fat and 60% more lean mass compared to a well-rested group, even on the same calorie deficit. Cortisol from chronic stress increases water retention and can drive higher calorie intake through appetite changes.

Your calorie target is not fixed. As you lose weight, your TDEE decreases because you are moving a smaller body. Metabolic adaptation also plays a role: your body becomes slightly more efficient during prolonged dieting, reducing energy expenditure by roughly 5 to 15% beyond what weight change alone would predict, according to research published in Obesity.

In practice, this means you should expect to adjust. Weigh yourself daily and track a 7-day rolling average. If your weekly average weight has not changed for 2 to 3 weeks and you are confident your tracking is accurate, reduce intake by 100 to 200 calories or increase activity slightly.

Avoid the temptation to make large cuts. Dropping 500 calories at once when progress stalls leads to the same sustainability problems as starting too aggressively. Small, incremental adjustments preserve adherence and lean mass.

Total calories determine whether you lose weight. But how you distribute those calories across protein, carbs, and fat affects what kind of weight you lose and how you feel during the process.

Protein is the most important macro during a calorie deficit. A meta-analysis in the American Journal of Clinical Nutrition found that higher protein intake (1.2 to 1.6 grams per kilogram of body weight per day) during calorie restriction preserves lean mass and increases satiety. For most people, this translates to roughly 0.7 to 1 gram of protein per pound of body weight.

Beyond protein, the split between carbs and fat is less critical for fat loss specifically. Choose a distribution that supports your energy levels and food preferences. Adherence matters more than optimization. For a deeper dive on building sustainable tracking habits, see our Ultimate Guide to Calorie Tracking.

ORI uses your age, weight, height, activity level, and goal to calculate a personalized calorie target. As you log meals and track weight, the AI adjusts your targets based on real progress instead of static formulas.

You do not need to run equations or guess at activity multipliers. ORI handles the math so you can focus on the food.