The right calorie deficit for most people falls between 300 and 500 calories below their maintenance level, which translates to roughly half a pound to one pound of weight loss per week. But the exact number depends on your starting point, how active you are, and how much weight you have to lose. Here’s how to find yours.
First, Find Your Maintenance Calories
Your calorie deficit is measured against your total daily energy expenditure (TDEE), the number of calories your body burns in a full day including all movement and digestion. To find it, you start with your basal metabolic rate (BMR), which is the energy your body uses just to stay alive at rest. The Harris-Benedict equation is one of the most commonly used formulas:
- Males: BMR = 88.362 + (13.397 × weight in kg) + (4.799 × height in cm) − (5.677 × age in years)
- Females: BMR = 447.593 + (9.247 × weight in kg) + (3.098 × height in cm) − (4.330 × age in years)
Once you have your BMR, multiply it by an activity factor that reflects your daily life:
- Sedentary (desk job, little exercise): multiply by 1.2
- Lightly active (light exercise 1–3 days per week): multiply by 1.375
- Moderately active (moderate exercise 3–5 days per week): multiply by 1.55
- Very active (heavy exercise 6–7 days per week): multiply by 1.725
The result is your estimated TDEE. For example, a 35-year-old woman who weighs 75 kg (165 lbs), stands 165 cm (5’5″), and exercises moderately would have a BMR of about 1,462 calories. Multiplied by 1.55, her estimated daily burn is roughly 2,266 calories. That’s the number she’d subtract from to create a deficit.
Keep in mind that any formula is an estimate. Most people overestimate their activity level, so if you’re unsure, start with the lower multiplier. You can always adjust based on real-world results over the first two to three weeks.
How Large Your Deficit Should Be
Cutting about 500 calories per day from your usual intake typically produces about half a pound to one pound of weight loss per week. The CDC recommends aiming for one to two pounds per week as a sustainable pace, and people who lose weight gradually are more likely to keep it off than those who drop it quickly.
A 500-calorie daily deficit is the most common starting point, but it isn’t the right number for everyone. Someone with a TDEE of 1,800 calories would be eating only 1,300 on a 500-calorie deficit, which leaves very little room for adequate nutrition. Someone burning 3,000 calories a day, on the other hand, could handle a 500 or even 750-calorie deficit without much difficulty. The deficit needs to be proportional to what you’re working with.
Your body fat percentage plays a role here too. People carrying more body fat can generally tolerate a larger deficit because their bodies have more stored energy to draw from. A person at 25% body fat can typically sustain a more aggressive cut than someone already at 15%, who would need a smaller, more conservative deficit to avoid losing muscle. As a rough principle: the leaner you are, the smaller your deficit should be.
Calorie Floors You Shouldn’t Drop Below
Harvard Health Publishing recommends that women eat no fewer than 1,200 calories per day and men no fewer than 1,500 calories per day unless supervised by a health professional. Eating below these thresholds makes it very difficult to get enough vitamins, minerals, and fiber from food alone, and it significantly increases the risk of muscle loss, fatigue, and nutrient deficiencies.
If your calculated deficit would put you below these floors, reduce the size of the deficit and make up the difference by adding more movement to your day. A 250-calorie deficit combined with a daily 30-minute walk will get you to a similar place as a 500-calorie food restriction, without the nutritional tradeoffs.
Protect Your Muscle While Losing Fat
When you eat fewer calories than you burn, your body pulls energy from both fat and muscle tissue. The goal is to shift that ratio heavily toward fat loss, and protein intake is the biggest dietary lever you have. Research published in the International Journal of Sport Nutrition and Exercise Metabolism recommends 1.6 to 2.4 grams of protein per kilogram of body weight per day during a calorie deficit. For a 75 kg (165 lb) person, that’s roughly 120 to 180 grams of protein daily.
Resistance training is the other half of the equation. Lifting weights or doing bodyweight exercises signals your body to preserve muscle, even when calories are low. Without that signal, you’ll lose more lean tissue, your metabolism will slow faster, and the weight you lose will include a higher proportion of muscle rather than fat.
Why Your Deficit Stops Working
Almost everyone hits a point where weight loss stalls despite sticking to the same calorie target. This is normal, and understanding why it happens helps you respond correctly instead of giving up.
In the first few weeks of a deficit, weight drops quickly because your body burns through its glycogen stores, which are bound to water. That initial drop is largely water weight, not fat. Once glycogen stores are depleted, the rate of loss slows to reflect actual fat burning.
Over time, a second factor kicks in. As you lose weight, your body becomes smaller and requires fewer calories to function. You also lose some muscle along with fat, which further reduces your metabolic rate. Eventually, the calories you’re eating match the calories your now-smaller body burns, and weight loss stops entirely.
When this happens, you have two options: slightly reduce your calorie intake (as long as you stay above the minimum floors) or increase your physical activity. The Mayo Clinic notes that using the same approach that worked initially may maintain your current weight, but it won’t produce further loss. Recalculating your TDEE at your new weight gives you an updated target to work from.
Signs Your Deficit Is Too Aggressive
A well-sized deficit should feel manageable. You’ll be somewhat hungry at times, but you should still have energy to get through your day and your workouts. If you notice several of the following, your deficit is likely too large:
- Persistent fatigue or low energy that doesn’t improve with sleep
- Mood changes, including increased irritability or anxiety
- Hormonal disruptions, such as irregular menstrual cycles or noticeably lower libido
- Stalled weight loss that doesn’t budge for three or more weeks despite compliance
- Constant preoccupation with food that goes beyond normal hunger
These are signs your body is adapting to what it perceives as a threat. The fix is counterintuitive: eat slightly more. Adding 100 to 200 calories back per day, particularly from protein and complex carbohydrates, often restores energy and allows fat loss to resume. A slower deficit you can sustain for months will always outperform an aggressive one you abandon after three weeks.
Putting It Together
Start by estimating your TDEE using the formula and activity multiplier above. Subtract 300 to 500 calories to set your initial target, making sure you stay above 1,200 (women) or 1,500 (men). Aim for protein at 1.6 to 2.4 grams per kilogram of body weight and include resistance training at least two to three times per week.
Track your weight weekly, ideally at the same time of day, and look at the trend over two to three weeks rather than any single weigh-in. If you’re losing between half a pound and two pounds per week, your deficit is in the right range. If you’re losing faster than that, eat a bit more. If nothing is moving after three weeks of consistent tracking, reduce calories by another 100 to 150 or add more activity. The right deficit isn’t a fixed number. It’s a moving target you adjust as your body changes.