To lose weight, you need to eat fewer calories than your body burns each day. For most adults, that means eating roughly 500 calories below your daily maintenance level, which produces about 1 to 2 pounds of weight loss per week. The exact number depends on your age, sex, height, weight, and how active you are, but a realistic starting range for most people is 1,500 to 2,000 calories per day for women and 2,000 to 2,500 for men.
How Your Body Burns Calories
Your total daily energy expenditure has three main components. The largest is your basal metabolic rate, the energy your body uses just to keep you alive: breathing, circulating blood, maintaining body temperature, and running your organs. This accounts for roughly 60 to 70 percent of the calories you burn each day, even if you never leave the couch.
The second component is physical activity, everything from walking to the kitchen to running five miles. The third is the thermic effect of food, the energy your body spends digesting and absorbing what you eat. That piece accounts for about 10 percent of your daily total. Add all three together and you get the number of calories you need to maintain your current weight. Eat below that number consistently, and you lose weight.
Finding Your Maintenance Calories
The USDA’s Dietary Guidelines provide a useful starting point based on age, sex, and activity level. A sedentary woman between 26 and 45 typically maintains her weight on about 1,800 calories per day. A moderately active woman in the same age range needs around 2,000. For sedentary men aged 26 to 45, maintenance sits around 2,200 to 2,400 calories. Moderately active men need about 2,600.
Activity level makes a real difference. “Sedentary” means you do little beyond the basic movements of daily living. “Moderately active” is the equivalent of walking 1.5 to 3 miles a day at a brisk pace on top of your normal routine. If you exercise intensely most days, your maintenance needs can climb to 2,800 or 3,000 calories for men and 2,200 to 2,400 for women.
These are population averages. Your actual number depends on your specific body size and composition. Online TDEE calculators that ask for your height, weight, age, and activity level can give you a more personalized estimate. From there, subtract 500 calories per day to lose about one pound per week, or 250 for a slower, more gradual approach.
How Big Should Your Deficit Be?
The CDC recommends losing 1 to 2 pounds per week for sustainable results. People who lose weight at this gradual pace are more likely to keep it off than those who drop weight faster. Since a pound of body fat stores roughly 3,500 calories, a daily deficit of 500 calories lines up with about one pound per week. A 1,000-calorie daily deficit produces closer to two pounds, but that level of restriction is harder to maintain and more likely to leave you hungry, tired, and nutrient-depleted.
There’s a practical floor to how low you should go. Most nutrition professionals advise women not to eat below 1,200 calories per day and men not to go below 1,500 without medical supervision. Dropping too far below those levels makes it very difficult to get adequate vitamins, minerals, protein, and fiber. It can also slow your metabolism, making future weight loss harder.
A Practical Calorie Range by Age and Sex
Here’s a simplified look at what “eating to lose weight” actually looks like in numbers, based on USDA maintenance estimates minus a 500-calorie deficit:
- Women aged 19 to 30, sedentary: Maintenance is about 1,800 to 2,000 calories. A weight-loss target would be roughly 1,300 to 1,500.
- Women aged 31 to 50, sedentary: Maintenance is about 1,800. A weight-loss target would be roughly 1,300.
- Men aged 19 to 30, sedentary: Maintenance is about 2,400 to 2,600. A weight-loss target would be roughly 1,900 to 2,100.
- Men aged 31 to 50, sedentary: Maintenance is about 2,200 to 2,400. A weight-loss target would be roughly 1,700 to 1,900.
If you’re moderately active or active, your maintenance number is higher, which means your weight-loss calorie target is also higher. This is one reason exercise helps: it lets you eat more while still losing weight, making the whole process more sustainable.
Why What You Eat Matters as Much as How Much
Hitting a calorie target is easier when your food keeps you full. This is where energy density comes in. Energy density is simply the number of calories packed into a given weight of food. Foods with low energy density, like fruits, vegetables, and broth-based soups, tend to be high in water and fiber but low in fat. You can eat a large volume of them without consuming many calories, which helps you feel satisfied on a reduced-calorie diet.
Compare a cup of raw spinach (about 7 calories) to a cup of granola (about 500 calories). Both fill space in your stomach, but the spinach lets you eat far more food for fewer calories. Adding vegetables to meals you already enjoy, like mixing chopped spinach or shredded zucchini into omelets, soups, or pasta dishes, increases the volume of your plate without significantly increasing the calorie count.
Fiber is a major driver of fullness. Research published in Frontiers in Nutrition found that people who increased their fiber intake to around 40 grams per day experienced meaningful weight loss. Most Americans eat only about 15 grams daily. You don’t need to triple your intake overnight, but gradually adding more beans, lentils, whole grains, fruits, and vegetables to your meals can make eating less feel like eating more.
Adjusting as You Go
Your calorie needs aren’t static. As you lose weight, your body gets smaller and burns fewer calories at rest. Someone who loses 20 pounds will have a lower maintenance number than they did at their starting weight, which means the deficit that initially produced steady loss may eventually stop working. This is normal, not a sign that something is broken.
When weight loss stalls, you have two options: reduce your intake slightly (by 100 to 200 calories) or increase your activity level. Adding even modest movement, like a daily 30-minute walk, can bump your daily burn by 150 to 200 calories without requiring you to eat less food.
Tracking your intake for even a few weeks can be eye-opening. Most people underestimate how much they eat by 20 to 40 percent. You don’t need to count calories forever, but a short tracking period helps you calibrate your sense of portion sizes and identify where extra calories tend to sneak in, whether that’s cooking oil, beverages, or after-dinner snacking.
Protein Keeps You on Track
When you’re eating in a calorie deficit, getting enough protein helps preserve muscle mass and keeps hunger in check. Protein is the most satiating of the three macronutrients, meaning it makes you feel fuller for longer compared to the same number of calories from carbohydrates or fat. Aiming for 25 to 30 grams of protein per meal is a practical target for most people trying to lose weight. Good sources include chicken, fish, eggs, Greek yogurt, beans, and lentils.
Losing muscle along with fat is one of the biggest downsides of aggressive calorie restriction. Muscle tissue burns more calories at rest than fat tissue does, so preserving it helps keep your metabolism from slowing down more than necessary. Combining adequate protein with some form of resistance exercise, even bodyweight exercises a few times per week, makes a significant difference in the quality of weight you lose.