Start with Your Maintenance Calories
Before you can set a target for weight loss, you need to know how many calories your body burns each day at your current activity level. That number is your TDEE (Total Daily Energy Expenditure). Eating at your TDEE keeps your weight exactly where it is. To lose weight, you eat below it.
If you do not know your TDEE yet, read our guide on how to calculate your TDEE or use our calorie calculator to get your number in seconds.
The Calorie Deficit Formula
Weight loss comes down to one relationship: calories in versus calories out. One pound of body fat stores approximately 3,500 calories of energy. To lose that pound, you need to burn 3,500 more calories than you eat over a period of time.
The size of your deficit determines how fast you lose weight:
- 250 cal/day deficit: about 0.5 lb per week (slow and sustainable)
- 500 cal/day deficit: about 1 lb per week (the most commonly recommended pace)
- 750 cal/day deficit: about 1.5 lbs per week
- 1,000 cal/day deficit: about 2 lbs per week (generally the safe maximum)
Deficits larger than 1,000 calories per day tend to cause muscle loss, nutritional deficiencies, fatigue, and unsustainable hunger. Faster is not always better when the result is muscle loss and rebound weight gain.
Minimum Calorie Floors
No matter how large your deficit calculates out to be, do not go below these minimums:
- Women: 1,200 calories per day
- Men: 1,500 calories per day
Below these thresholds, it becomes very difficult to get enough protein, vitamins, and minerals. Metabolic rate slows down, muscle is lost faster, and the diet becomes impossible to sustain. If your calculated target falls below these floors, the answer is not to eat less. It is to increase your activity level so your TDEE is higher, which gives you more room to create a deficit while still eating enough.
Worked Example
Using the same woman from our TDEE example: 35 years old, 145 lbs, moderately active, with a TDEE of 2,122 calories per day. She wants to lose 20 pounds.
Target: 1 lb per week (500 cal/day deficit)
Time to reach goal:
1,622 calories is comfortably above the 1,200 minimum for women, which means this is a safe and realistic plan. She can also use our calorie calculator to see her target broken down by goal and activity level side by side.
Why the 3,500 Calorie Rule Is an Approximation
The 3,500 calories per pound figure is a useful planning estimate, not a precise biological constant. In practice, weight loss slows over time because as you get lighter, your TDEE drops. A 145-pound person burns fewer calories at rest than a 165-pound person. This is why most people find weight loss gets progressively harder the closer they get to their goal, and why periodic recalculations of your TDEE matter.
Tips for Hitting Your Calorie Target
- Prioritize protein. Protein keeps you fuller longer and preserves muscle during a deficit. Aim for 0.7 to 1 gram of protein per pound of body weight per day. At 145 lbs, that is 100 to 145 grams of protein daily.
- Track food for at least two weeks. Most people significantly underestimate their intake. Logging precisely at the start, even temporarily, builds awareness and reveals where extra calories are hiding.
- Do not cut too fast. A 500 cal/day deficit is the sweet spot for most people. Larger deficits make it harder to train effectively, harder to recover, and harder to stick to the plan long enough to matter.
- Recalculate as you lose weight. For every 10 pounds you lose, recalculate your TDEE. Your calorie target will need to drop slightly to maintain the same rate of loss.
Frequently Asked Questions
How do I know if my calorie target is working?
Weigh yourself at the same time each morning after using the bathroom, before eating or drinking. Average the readings across a full week. A weekly average that is dropping by your target amount (0.5 to 1 lb per week for a 250 to 500 cal deficit) means it is working. Daily fluctuations of 1 to 2 pounds are normal due to water, salt, and digestion, and are not meaningful on their own.
Should I eat back the calories I burn during exercise?
If you calculated your TDEE using an activity multiplier that already accounts for your exercise (moderately active, very active, etc.), then no. Your TDEE already includes those calories. Only eat back exercise calories if you used the sedentary multiplier and added workouts on top. Eating back calories is a common reason people stall despite thinking they are in a deficit.
Why did I stop losing weight after a few weeks?
Several things can stall weight loss: your TDEE dropped as your body weight dropped (so you are no longer in a deficit), water retention is masking fat loss on the scale, or calorie intake has crept up through unmeasured additions. Try recalculating your TDEE at your current weight, tightening up your food tracking, and giving it two to three more weeks before drawing conclusions.
Is a 1,200 calorie diet safe?
For most women, 1,200 calories is the floor, not a target to aim for. Eating at exactly 1,200 calories is difficult to sustain, leaves little room for nutritional variety, and tends to accelerate muscle loss. If your deficit calculation lands you at or near 1,200 calories, consider a smaller deficit (250 to 350 calories) for slower but more sustainable progress, combined with increasing activity to raise your TDEE.
Does it matter when I eat my calories?
Total daily calories matter far more than meal timing for weight loss. Skipping breakfast, intermittent fasting, or eating three large meals versus six small ones all produce similar results when total calories are the same. Choose a meal pattern that fits your schedule and helps you stay within your target consistently.