A daily calorie deficit of 500 calories is the most widely recommended starting point for weight loss, and it typically produces about half a pound to one pound of loss per week. But the right deficit for you depends on your size, activity level, and how much weight you have to lose. A smaller person burning 1,800 calories a day needs a very different approach than a larger person burning 2,800.
The 500-Calorie Starting Point
The old rule of thumb said that 3,500 calories equals one pound of fat, so cutting 500 calories a day for seven days should produce exactly one pound of weight loss per week. That math is tidy, but the Mayo Clinic notes it doesn’t hold true for everyone. When you lose weight, you lose a mix of fat, lean tissue, and water, not pure fat. And as your body gets smaller, it burns fewer calories, which means the same 500-calorie deficit produces progressively less weight loss over time.
Still, 500 calories per day is a practical benchmark. It’s large enough to produce visible results within a few weeks but moderate enough that most people can sustain it without feeling miserable. If you want slower, more gradual loss, a 250-calorie daily deficit (roughly half a pound per week) works too and can feel more manageable for people who are already relatively lean or who find hunger difficult to tolerate.
Why a Percentage May Work Better Than a Fixed Number
A flat 500-calorie cut treats everyone the same, which is the problem. If your body burns 2,500 calories a day, a 500-calorie deficit is a 20% reduction. If your body only burns 1,600 calories a day, that same 500 calories is a 31% cut, which is far more aggressive and harder to maintain. That’s why many nutrition coaches recommend setting your deficit as a percentage of your total daily energy expenditure, typically between 15% and 25%.
A 20% reduction is a reasonable middle ground for most people. It’s large enough to move the scale but small enough to preserve energy levels, workout performance, and sanity. Someone burning 2,400 calories a day would aim for roughly 1,920 calories. Someone burning 1,800 would target about 1,440.
How to Estimate Your Daily Burn
Your total daily energy expenditure has two main components: your resting metabolic rate (the calories your body burns just keeping you alive) and the calories you burn through movement. The most commonly used formula for estimating resting metabolism is the Mifflin-St Jeor equation, which uses your weight, height, age, and sex. For men, it’s (10 × weight in kg) + (6.25 × height in cm) – (5 × age) + 5. For women, it’s the same formula but minus 161 instead of plus 5.
That number represents what you’d burn lying in bed all day. To estimate your actual daily burn, you multiply by an activity factor: 1.2 for a sedentary desk job, 1.375 if you exercise lightly a few times a week, 1.55 for moderate exercise most days, and 1.725 for intense daily training. Most people overestimate their activity level, so if you’re unsure, start with the lower multiplier and adjust based on what the scale does over two to three weeks.
Online TDEE calculators do this math for you and are a fine starting point, but treat the result as an estimate, not a precise measurement. Your actual burn can vary significantly based on genetics, hormones, sleep quality, and how much you move outside of formal exercise.
Non-Exercise Movement Matters More Than You Think
The calories you burn through everyday movement, things like walking to the kitchen, fidgeting, standing while you work, and carrying groceries, often account for more of your daily burn than your gym sessions do. Researchers call this non-exercise activity thermogenesis, or NEAT, and it varies enormously from person to person. According to research from the Mayo Clinic, NEAT can differ by up to 2,000 calories a day between two people of similar size.
One study comparing lean and obese sedentary people with similar jobs found that obese individuals sat about two and a half hours more per day, while lean individuals stood or walked more than two additional hours daily. This matters for your deficit because when you start eating less, your body often compensates by reducing NEAT unconsciously. You fidget less, take fewer steps, and generally move less without realizing it. Keeping your daily movement high, even just walking more, helps protect your deficit from this invisible erosion.
Your Metabolism Will Adapt
One of the most frustrating parts of dieting is that your body fights back. When you eat less, your metabolism slows beyond what the loss of body weight alone would predict. Research measuring this effect found that after just one week of calorie restriction, people’s daily energy expenditure dropped by an average of 178 calories more than expected. That adaptation stayed relatively stable throughout the dieting period and varied significantly between individuals.
The practical consequence: a 100-calorie-per-day greater metabolic slowdown in the first week predicted about 2 kg (4.4 pounds) less weight loss over six weeks. This is why weight loss stalls are so common. The deficit you calculated at the start gradually shrinks as your body adjusts, and you either need to eat a little less, move a little more, or accept a slower rate of loss. Building in periodic breaks from dieting, eating at maintenance for a week or two, may help manage this adaptation, though the research on this strategy is still evolving.
How Much Protein to Eat During a Deficit
When you’re in a calorie deficit, your body doesn’t just burn fat. It can also break down muscle for energy, especially if your protein intake is too low. Eating enough protein is the single most important nutritional strategy for preserving muscle while you lose weight.
For people who exercise regularly, 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 deficit. For a 75 kg (165 lb) person, that’s 120 to 180 grams of protein daily. Resistance-trained individuals may benefit from the higher end of that range. Going above 2.4 grams per kilogram doesn’t appear to provide additional muscle-sparing benefits.
If you don’t exercise much, you can aim for the lower end. But even for non-athletes, prioritizing protein helps with satiety. Protein is the most filling macronutrient, so a higher-protein diet makes it easier to stick to a deficit without constant hunger.
Minimum Calorie Floors
There’s a lower limit to how aggressively you should cut. Harvard Health Publishing recommends that calorie intake should not fall below 1,200 a day for women or 1,500 a day for men without medical supervision. Dropping below these levels makes it very difficult to get adequate vitamins, minerals, and fiber from food alone, and it increases the risk of muscle loss, hormonal disruption, and nutrient deficiencies.
Signs that your deficit is too aggressive include feeling tired all the time, getting sick frequently and recovering slowly, poor concentration, feeling cold most of the time, wounds healing slowly, and persistent low mood. Hair loss, loss of menstrual periods in women, and a dramatic drop in exercise performance are additional red flags. If you’re experiencing several of these, your body is telling you it doesn’t have enough fuel, and you need to eat more, not push through.
Putting It All Together
Start by estimating your total daily energy expenditure using an online calculator or the Mifflin-St Jeor equation with an activity multiplier. Subtract 15% to 25% of that number, or roughly 500 calories if you prefer simplicity. Make sure the result doesn’t fall below 1,200 calories for women or 1,500 for men. Keep your protein high, at least 1.6 grams per kilogram of body weight, and maintain your daily movement outside of formal exercise.
Track your weight over two to three weeks before making adjustments. Daily weight fluctuates due to water retention, sodium intake, and digestive contents, so weekly averages are more useful than any single weigh-in. If you’re losing 0.5 to 1 pound per week on average, your deficit is working. If the scale isn’t moving, your actual burn is likely lower than your estimate, and you’ll need to trim another 100 to 200 calories or add more movement. Weight loss is an iterative process, not a one-time calculation.