To lose 10 pounds, most people need to eat 500 fewer calories per day than their body burns, which produces roughly one pound of weight loss per week and gets you to your goal in about 10 weeks. The exact number of calories you should eat depends on your current size, age, sex, and activity level, but the math is straightforward once you know your starting point.
How a Calorie Deficit Produces Weight Loss
Your body burns a certain number of calories each day just by existing and moving around. This is your total daily energy expenditure, or maintenance calories. When you consistently eat less than that number, your body pulls from stored energy (mostly fat) to make up the difference, and you lose weight over time.
A long-standing rule of thumb says that a deficit of 3,500 calories equals one pound of body weight lost. That math traces back to a calculation assuming you’re losing pure fat tissue, which is about 87% fat by weight. In reality, you lose some muscle along with fat, and your metabolism adjusts as you shrink. For people with a relatively high amount of body fat, the 3,500-calorie rule holds up reasonably well. For leaner people, the actual energy cost per pound lost is somewhat lower, meaning weight can come off a bit faster than the rule predicts early on, then slow down.
For practical planning, a daily deficit of 500 calories translates to about one pound per week. A 1,000-calorie daily deficit doubles the pace to roughly two pounds per week. The CDC notes that losing one to two pounds per week is the rate most strongly associated with keeping the weight off long-term.
Finding Your Maintenance Calories
Before you can set a calorie target, you need a reasonable estimate of how many calories your body uses each day. The most widely validated formula for this starts by calculating your resting metabolic rate, then adjusting for how active you are.
For men, the base calculation is: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5. For women, it’s the same formula but you subtract 161 instead of adding 5. That gives you a resting number. Then multiply by an activity factor:
- Sedentary (desk job, little exercise): multiply by 1.2
- Lightly active (light exercise 1-3 days/week): multiply by 1.375
- Moderately active (moderate exercise 3-5 days/week): multiply by 1.55
- Active (hard exercise 6-7 days/week): multiply by 1.725
- Very active (intense daily training or physical job): multiply by 1.9
As a quick reference, the Dietary Guidelines for Americans estimates that adult women generally need 1,600 to 2,400 calories per day, while adult men need 2,000 to 3,000. Those ranges are based on a reference woman who is 5’4″ and 126 pounds and a reference man who is 5’10” and 154 pounds. If you’re larger or more active, your number will be higher.
A Worked Example
Take a 40-year-old woman who weighs 170 pounds (77 kg), stands 5’5″ (165 cm), and exercises a few times a week. Her resting metabolic rate works out to about 1,434 calories. Multiplied by 1.375 for light activity, her maintenance calories land around 1,972 per day. Subtracting 500 gives a daily target of roughly 1,470 calories to lose about one pound per week, reaching 10 pounds lost in 10 weeks.
A 35-year-old man at 200 pounds (91 kg) and 5’10” (178 cm) with moderate activity would have a maintenance level around 2,790 calories. A 500-calorie deficit puts his daily target at roughly 2,290, and a 750-calorie deficit (about 1.5 pounds per week) would mean eating around 2,040 calories daily, reaching 10 pounds in about seven weeks.
Why Your Calorie Needs Drop as You Lose Weight
One important thing the simple math doesn’t capture: your body fights back. Maintaining a 10% or greater reduction in body weight comes with roughly a 20-25% decline in daily energy expenditure. Part of that drop is straightforward physics, since a smaller body burns fewer calories. But about 10-15% of the decline goes beyond what the change in body size alone would explain. Your metabolism genuinely slows down in response to sustained calorie restriction, a process researchers call adaptive thermogenesis.
For a 10-pound goal, this effect is modest but real. You may notice that weight loss slows a bit in the final weeks. If your progress stalls, it usually means your maintenance calories have shifted downward and your original deficit has shrunk. You can either reduce intake slightly further or increase physical activity to restore the gap.
Calorie Floors You Shouldn’t Go Below
Cutting calories too aggressively backfires. The federal Dietary Guidelines explicitly state that calorie patterns of 1,000 and 1,200 per day are not designed for adults. Dropping below roughly 1,200 calories (for smaller, less active women) or 1,500 calories (for most men) makes it very difficult to meet basic nutrient needs for vitamins, minerals, and fiber. It also increases the proportion of weight you lose as muscle rather than fat, which works against you in the long run because muscle tissue is what keeps your metabolism running.
If a 500-calorie daily deficit would put you below these floors, a smaller deficit of 250-300 calories combined with increased physical activity is a safer approach. The timeline stretches out, but the weight loss is more sustainable and preserves more of your lean tissue.
Protecting Muscle While Cutting Calories
When you eat less than your body needs, it doesn’t pull exclusively from fat stores. Some muscle breaks down too, and the more aggressive the deficit, the more muscle you lose. This matters because muscle is metabolically active tissue. Losing it lowers your daily calorie burn and makes regain more likely.
The single most effective strategy for protecting muscle during weight loss is eating enough protein. A 2024 meta-analysis found that intakes above 1.3 grams of protein per kilogram of body weight per day (about 0.6 grams per pound) are associated with actual increases in muscle mass even during a calorie deficit, while intakes below 1.0 gram per kilogram raise the risk of muscle loss. For a 170-pound person, that means aiming for at least 100 grams of protein daily. Spreading it across meals rather than loading it into one sitting improves absorption.
Resistance training is the other half of the equation. Lifting weights or doing bodyweight exercises signals your body to hold onto muscle and preferentially burn fat for energy. Even two to three sessions per week makes a meaningful difference.
A Realistic Timeline for 10 Pounds
At a 500-calorie daily deficit, expect to lose 10 pounds in roughly 10 to 12 weeks. The first week or two often shows a larger drop (3-5 pounds) due to water and glycogen loss, not pure fat. That early number will level off, and the real rate of about one pound per week kicks in.
At a 750-calorie daily deficit, the timeline compresses to about 7-8 weeks. At 1,000 calories per day below maintenance (the upper end of what’s generally advisable), you could reach the goal in 5-6 weeks, though this pace is harder to sustain and carries more risk of muscle loss and nutrient gaps.
Weight doesn’t drop in a perfectly straight line. Day-to-day fluctuations of 1-3 pounds from water retention, sodium intake, and hormonal shifts are normal. Tracking a weekly average rather than obsessing over a single morning weigh-in gives you a much clearer picture of actual progress. If your weekly average hasn’t budged in two to three weeks, your deficit has likely closed and it’s time to recalculate.
Putting It All Together
Start by estimating your maintenance calories using the formula and activity multipliers above, or use any reputable online calculator based on the same equation. Subtract 500 calories from that number. That’s your daily target. Make sure the result doesn’t fall below 1,200 for women or 1,500 for men. Prioritize protein at roughly 0.6 grams per pound of body weight, and include some form of resistance exercise to protect the muscle you already have.
At that pace, 10 pounds is a 10-to-12-week project. Expect the scale to wobble, expect a slight slowdown as your body adapts, and recalculate your target if you hit a plateau lasting more than two or three weeks. Ten pounds is an achievable, moderate goal, and a steady deficit is the most reliable way to get there and stay there.