To lose weight, you need to eat fewer calories than your body burns each day. For most people, that means cutting 500 calories per day from their maintenance level, which typically produces about one to two pounds of weight loss per week. But the specific number you should eat depends on your size, age, sex, and how active you are. There’s no single calorie target that works for everyone.
How to Find Your Maintenance Calories
Your body burns a baseline number of calories just by existing. Breathing, circulating blood, repairing cells, and keeping your organs running all require energy. This baseline is called your basal metabolic rate, or BMR. You can estimate it using the Harris-Benedict equation:
- Men: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) − (5.677 × age in years)
- Women: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) − (4.330 × age in years)
To convert pounds to kilograms, divide by 2.2. To convert inches to centimeters, multiply by 2.54. A 35-year-old woman who weighs 170 pounds (77 kg) and stands 5’6″ (168 cm) would have a BMR of roughly 1,488 calories per day. That’s what her body burns at complete rest.
But you don’t lie still all day. Your actual daily calorie burn, often called total daily energy expenditure (TDEE), accounts for movement, exercise, and even digesting food. To estimate it, multiply your BMR by an activity factor:
- Sedentary (desk job, little exercise): BMR × 1.2
- Lightly active (light exercise 1–3 days per week): BMR × 1.375
- Moderately active (moderate exercise 3–5 days per week): BMR × 1.55
- Very active (hard exercise 6–7 days per week): BMR × 1.725
- Super active (intense training plus a physical job): BMR × 1.9
Using the example above, if that same woman exercises three times a week, her estimated TDEE would be about 2,046 calories per day (1,488 × 1.375). That’s roughly what she’d need to eat to stay the same weight. To lose weight, she’d eat less than that number.
How Big Your Deficit Should Be
A daily deficit of 500 calories is the most commonly recommended starting point. Harvard Health Publishing notes that cutting 500 to 1,000 calories per day from your maintenance level produces a loss of one to two pounds per week, a rate that experts consider safe and sustainable. For the woman in our example, that would mean eating roughly 1,500 to 1,550 calories per day.
A 1,000-calorie daily deficit is more aggressive and will produce faster results, but it’s harder to maintain and more likely to leave you feeling drained, hungry, and irritable. For many people, especially those who are shorter or less active, a 1,000-calorie cut would push intake dangerously low. Harvard Health recommends that women not go below 1,200 calories per day and men not go below 1,500 calories per day without medical supervision. Below those thresholds, it becomes very difficult to get adequate nutrition, and the risk of muscle loss, nutrient deficiencies, and metabolic slowdown increases significantly.
Why the “3,500 Calories per Pound” Rule Is Misleading
You’ve probably heard that cutting 3,500 calories equals one pound of fat lost. It’s a tidy number, but research has shown it overpromises. When researchers tested this rule against data from seven closely monitored weight loss studies, where participants lived in research facilities for up to three months, most people lost significantly less weight than the rule predicted.
The core problem is that the rule treats your body like a simple math equation. In reality, your metabolism adjusts as you lose weight. A smaller body burns fewer calories, so the same deficit that produced steady weight loss in month one will produce slower results by month three. The rule also assumes everyone responds to the same calorie cut equally, which research has shown isn’t true. People with more weight to lose tend to see faster initial results, while smaller individuals may lose more slowly on the same deficit.
The National Institutes of Health offers a free online Body Weight Planner that uses a more sophisticated model. It factors in your starting weight, goal weight, and timeline to generate a more realistic calorie target and expected rate of loss.
How Age Affects Your Calorie Needs
One piece of good news: your metabolism is more stable than most people think. A landmark study published in Science found that metabolic rate, adjusted for body size, stays remarkably consistent from age 20 through 60. The common belief that your metabolism tanks in your 30s or 40s isn’t supported by the data.
After 60, metabolic rate does begin to decline, dropping by about 0.7% per year. By age 90 and beyond, total energy expenditure is roughly 26% lower than in middle-aged adults. But for most people reading this article, age alone isn’t the reason the scale isn’t moving. Changes in muscle mass, activity level, and eating habits play a much larger role than the calendar.
What a Weight Loss Plateau Means
Almost everyone who cuts calories will eventually hit a stretch where the scale stops moving. This happens because your body adapts. As you lose weight, you become a smaller person who requires fewer calories for everything, from walking up stairs to sleeping. The deficit that worked at 200 pounds may put you at maintenance by 180 pounds.
When this happens, you have a few practical options. You can reduce your calorie intake by another small amount, perhaps 100 to 200 calories. You can increase your activity level to burn more. Or you can add strength training to build muscle, which is more metabolically active than fat and nudges your daily calorie burn upward. Recalculating your TDEE using your current weight is a good first step, since many people are still eating for the body they had 20 or 30 pounds ago.
Putting It All Together
Here’s the practical process. First, estimate your BMR using the formula above or an online calculator. Multiply it by the activity factor that honestly reflects your lifestyle (most people overestimate their activity level). That gives you your maintenance calories. Then subtract 500 calories for steady, sustainable weight loss of about a pound per week.
If your calculated target falls below 1,200 (for women) or 1,500 (for men), you’re better off using a smaller calorie deficit and adding exercise to create the rest of the gap. A combination of eating slightly less and moving slightly more is easier to stick with than severe restriction alone. It also preserves more muscle, which matters for both your metabolism and how you look and feel as the weight comes off.
Track your intake for at least two to three weeks before making adjustments. Weight fluctuates daily due to water retention, sodium intake, and hormonal shifts, so a single weigh-in tells you very little. The trend over weeks is what matters. If you’re losing half a pound to two pounds per week on average, you’re in the right range. If nothing has budged after three consistent weeks, your calorie target likely needs a small downward adjustment or your tracking may be less accurate than you think.