How Many Calories Should You Eat to Lose Weight?

How many calories should you eat to lose weight? Eat 300 to 750 calories a day below what it takes to maintain your current weight, which for most adults lands somewhere between 1,500 and 2,200 calories a day depending on size, sex, and activity level. That range produces roughly 0.5 to 1 pound of fat loss per week, which is fast enough to see progress and slow enough to actually hold onto.

The honest answer is that your exact number depends on you, but the deficit size and the guardrails around it are the same for almost everyone. Here is how to land on a sensible target.

How many calories should you eat to lose weight?

First estimate your maintenance calories, the amount that keeps your weight roughly stable, then subtract 300 to 750 calories from that number. Maintenance varies a lot by bodyweight, height, sex, age, and how active you are day to day, which is why there is no single calorie number that works for everyone.

As a rough starting point, many adults maintain somewhere around 14 to 16 calories per pound of bodyweight with a typical activity level. So a 180 pound moderately active person might maintain around 2,500 to 2,900 calories and lose weight steadily eating 1,900 to 2,400. Treat any formula like this as a starting estimate you adjust from, not a fixed truth, since real-world tracking over a couple of weeks is what actually tells you your true number.

How big should the deficit be?

A daily deficit of 300 to 750 calories works well for most people, translating to roughly 0.5 to 1 pound (about 0.5 to 1 percent of bodyweight) lost per week. That pace is slow enough to preserve muscle and energy, and it is realistic to sustain for months, which matters more than any theoretical fastest path.

A deficit of around 1,000 calories a day is generally considered the upper limit, and pushing past that without medical supervision raises real risks: bigger drops in muscle mass, larger metabolic slowdowns, and diets that are miserable enough that most people quit. Slow and steady is not just the safe advice, it is usually the faster path to keeping the weight off.

Is there a floor you shouldn't eat below?

Yes. Most guidance puts a sensible floor around 1,200 calories a day for women and 1,500 a day for men. Going below that without medical guidance raises the risk of missing key nutrients, and very low calorie diets under about 800 calories a day need direct medical supervision.

These are floors, not goals. If your calculated deficit pushes you under one of these numbers, the fix is usually to add more activity rather than cut calories further, or to accept a slower rate of loss. There is rarely a good reason to eat less than this on your own.

Does protein matter while cutting calories?

Yes, more than almost anything else in a deficit. Eating enough protein, close to 1 gram per pound of bodyweight while you are cutting, is one of the best-supported ways to hold on to muscle while the scale drops. Without enough protein, a meaningful chunk of what you lose in a deficit is muscle instead of fat, which is the opposite of what most people actually want.

Keeping your training consistent matters just as much. Lifting through a deficit gives your body a reason to hold onto the muscle it has, even while calories are down, so this is not the time to stop training, if anything it is when consistency matters most.

How do you know if your deficit is actually working?

Track your weight trend over 2 to 3 weeks, not day to day. Daily weight swings from water, sodium, and digestion are normal and can hide or exaggerate real fat loss, so a single bad morning on the scale means nothing on its own. If your weekly average is dropping by roughly 0.5 to 1 percent of bodyweight, your current calories are working. If it has been flat for two to three weeks with honest tracking, your true maintenance is probably higher than you estimated, and it is time to cut a little further.

This is where most people's calorie math quietly falls apart, not because the plan is wrong, but because tracking is tedious and gets skipped after a few days. OneFit's meal scanning is built for exactly that gap: point your camera at a plate and it estimates the calories and protein in seconds, so the deficit you set on paper is the one you actually eat, week after week.

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FAQ

How many calories should I eat to lose weight? Start by eating 300 to 750 calories a day below what it takes to maintain your current weight. For most adults that lands somewhere between 1,500 and 2,200 calories a day, but it depends heavily on your size, sex, and activity level.

How big should my calorie deficit be? A deficit of 300 to 750 calories a day is enough for most people, producing roughly 0.5 to 1 pound of loss per week. Bigger deficits speed up short-term loss but increase muscle loss and make the diet harder to sustain.

Is a 1000 calorie deficit too much? For most people, yes. A 1,000 calorie daily deficit is considered an upper limit and is often too aggressive without medical supervision, since it raises the risk of losing muscle along with fat and makes the diet much harder to stick to.

What is the lowest number of calories I should eat? Most guidance puts a sensible floor around 1,200 calories a day for women and 1,500 for men, and going lower than that without medical guidance risks nutrient deficiencies. These are floors, not targets, most people should eat more than this.

How much protein do I need while eating in a deficit? Aim for the higher end of the normal range, close to 1 gram of protein per pound of bodyweight per day, since protein is what helps you hold on to muscle while losing fat.