To lose half a pound a week, you need to eat 250 calories fewer than your Total Daily Energy Expenditure (TDEE) each day. This daily deficit of 250 calories creates a cumulative weekly deficit of 1,750 calories, which corresponds to approximately half a pound of body fat. For example, if your daily maintenance level is 2,000 calories, your daily target would be 1,750 calories.
The Arithmetic of Half a Pound a Week
The calculation for gradual fat loss relies on standard calorie arithmetic. One pound of body fat contains approximately 3,500 calories of stored energy. Therefore, losing half a pound requires a weekly energy deficit of 1,750 calories.
When you divide 1,750 calories by 7 days, the result is a daily deficit of exactly 250 calories. To achieve this, you subtract 250 from your daily maintenance calories. The basic equation is simple.
Daily Calorie Target = Total Daily Energy Expenditure (TDEE) - 250
Your maintenance calories represent the total number of calories your body burns in a 24 hour period. If you consume exactly your TDEE, your weight remains stable. Consuming 250 calories below this number forces your body to draw the remaining energy from stored fat.
All calorie numbers are estimates rather than absolute values. Individual metabolic rates, digestion efficiency, and daily movement cause natural variations in energy expenditure.
Worked Examples for Common Maintenance Levels
Different individuals require different calorie targets based on their starting maintenance levels. Below are two worked examples showing how the 250-calorie deficit applies to different daily energy expenditures.
Example 1: The 2,000-Calorie Baseline
This example represents a typical daily expenditure for a moderately active individual or a sedentary person with a moderate body weight.
- Baseline TDEE: 2,000 calories per day
- Targeted Daily Deficit: 250 calories per day
- Calculation: 2,000 - 250 = 1,750
- Daily Calorie Target: 1,750 calories per day
- Weekly Deficit: 1,750 calories (approx. 0.5 pounds of fat loss)
Example 2: The 2,800-Calorie Baseline
This example represents a typical daily expenditure for an active individual, someone with a larger physical frame, or a person who engages in daily physical labor.
- Baseline TDEE: 2,800 calories per day
- Targeted Daily Deficit: 250 calories per day
- Calculation: 2,800 - 250 = 2,550
- Daily Calorie Target: 2,550 calories per day
- Weekly Deficit: 1,750 calories (approx. 0.5 pounds of fat loss)
You can run your own numbers in the calorie deficit calculator to determine your custom target based on your current height, weight, age, and activity level.
Understanding the Components of Your Energy Expenditure
To find your daily target, you must first estimate your Total Daily Energy Expenditure (TDEE). TDEE is built from two primary components, Basal Metabolic Rate (BMR) and your activity level.
Basal Metabolic Rate (BMR)
Your BMR is the baseline energy your body requires to perform basic life-sustaining functions. This includes breathing, circulating blood, and maintaining organ function at rest.
The Mifflin-St Jeor equation is a standard method used to calculate this baseline. It uses your sex, weight, height, and age to produce a daily calorie estimate.
The Activity Factor
Once you have your BMR, you multiply it by an activity factor to account for your daily movement. This multiplier ranges from sedentary to highly active.
- Sedentary (little to no exercise): BMR multiplied by 1.2
- Lightly active (light exercise 1 to 3 days per week): BMR multiplied by 1.375
- Moderately active (moderate exercise 3 to 5 days per week): BMR multiplied by 1.55
- Very active (hard exercise 6 to 7 days per week): BMR multiplied by 1.725
For instance, if your calculated BMR is 1,600 calories and you are lightly active, your estimated TDEE is 2,200 calories (1,600 multiplied by 1.375). A 250-calorie deficit would set your target at 1,950 calories per day.
How Weight Fluctuations Impact the Scale
A half-pound weight loss represents a real change in body tissue, but the scale may not show it immediately. Daily weight fluctuations can easily mask this gradual progress.
Water retention, sodium intake, and glycogen storage cause daily weight shifts of one to three pounds. A high-sodium meal can cause you to hold several pounds of water, even while you remain in a calorie deficit.
To track a half-pound weekly loss accurately, compare weekly averages rather than daily scale weights. It usually takes three to four weeks of consistent tracking to see a clear downward trend.
Can You Achieve a 250-Calorie Deficit Through Exercise Alone?
Yes. You can create a calorie deficit by increasing your physical activity, decreasing your food intake, or combining both.
A 250-calorie deficit is small enough to achieve through a daily 45-minute brisk walk. It can also be achieved by making small adjustments to your daily food portions.
Combining both methods is often the most sustainable approach. For example, you might eat 150 calories less and walk to burn an extra 100 calories.
What Happens If You Eat Below Your Daily Target?
Eating more than 250 calories below your TDEE will increase the rate of weight loss, but it may also increase hunger and muscle loss.
Larger deficits can make it harder to sustain the routine over several months. A consistent, moderate deficit is typically easier to maintain than a severe, erratic restriction.
Keeping the deficit at 250 calories helps preserve lean muscle mass during weight loss. This is particularly important for maintaining your baseline metabolic rate.
How Often Should You Recalculate Your Calorie Target?
You should recalculate your TDEE after every 5 to 10 pounds of weight loss. As your body weight decreases, your body requires less energy to move and function.
If you do not adjust your calorie target, your deficit will gradually shrink. Eventually, your new maintenance calories will match your intake, and weight loss will pause.
Treating your daily calorie deficit as a budget that you spend down toward a target over the day helps simplify this arithmetic, turning tracking into a clear daily goal.