Contents
To lose 2 pounds a week, the old arithmetic says cut about 1,000 a day from your burn. But 2 pounds a week is the ceiling of a sensible pace, not a default, and a target never goes below your resting burn. Whether that limit arrives before 2 pounds depends on your burn.
The arithmetic, in words
Take your daily burn. Subtract a cut. Check the result against your resting burn.
The cut comes from a pace. Mayo Clinic gives the old rule: about 3,500 calories make up about one pound of fat. Two pounds is 7,000 calories. Spread over seven days, that is 1,000 a day. One pound a week is 500 a day.
Mayo adds a caution to that rule: it is not true for everyone. We agree, and we will show why below. Treat the number as a starting point.
Example A: two pounds fits
This is an illustration, not a target for anyone. Take a man whose daily burn is 3,000 calories and whose resting burn is 1,800.
Two pounds a week needs a cut of 1,000 a day. His target is 2,000. That is above his resting burn of 1,800, so the pace fits his burn.
Example B: two pounds does not fit
Another illustration. Take a woman whose daily burn is 2,300 and whose resting burn is 1,450.
Two pounds a week needs a 1,000-a-day cut. That lands 150 below her resting burn, so the pace has to come down. At one and a half pounds a week, the cut is 750 a day (5,250 calories over seven days). Her target is 1,550, which is above her resting burn.
The same rule gave two different answers, and neither person did anything wrong. The difference was the burn, which is why we start with the burn and end with a pace.
When two pounds meets the floor
The National Academies report resting burn at 60 to 70 percent of total burn. A 1,000-a-day cut falls below your resting burn whenever your total burn is under roughly 2,500 (at a 60 percent share) to 3,300 (at 70 percent). That is our own arithmetic on their range, not a figure from the report.
If your total burn sits under that line, a calculator that says "cut 1,000 a day" gives you a number that needs checking. A calculator that never asks for your resting burn cannot tell you whether the target it gives is one you can use.
If your burn is very high or very low, check any target against your resting burn before you use it. The check takes one subtraction.
A target below your resting burn is a sign the pace is too fast, not a sign you should eat less.
Why the old rule drifts
The 3,500 rule treats your burn as fixed. It is not. As you get lighter, your body burns less.
Kevin Hall and colleagues built a dynamic model of adult body weight and published it in The Lancet in 2011. Their example was one simulated 100 kg sedentary man. For a cut of about 2 megajoules a day (roughly 480 calories), the static rule predicted 22 kg lost in the first year, about 100 percent more than their model. In the model, weight responds with a half-time of about a year.
Two limits apply. The figures come from one simulated man, in a model checked against small studies, not a measurement of you. And it assumes perfect adherence.
Hall's paper also gives the energy in body tissue: 39.5 megajoules per kilogram of fat and 7.6 per kilogram of lean mass. So the energy in a kilogram of weight change depends on what it is made of. A single calories-per-pound figure is a shortcut.
What to do instead: use the rule to set a first target, then re-check it every few weeks as your weight and burn change. Your weigh-ins tell you whether the target is working.
Choosing a pace
The CDC says people who lose weight gradually, about 1 to 2 pounds a week, are more likely to keep the weight off. Two pounds is the top of that range, not a default.
Faster paces carry costs. MedlinePlus says losing more than 1 or 2 pounds a week is not safe for most people, and that it can cost you muscle. It lists gallstones among the side effects of rapid loss. It also says people who lose weight quickly are much more likely to regain it.
Our view on pace: pick the pace your burn supports, and treat 2 pounds as a ceiling you may not reach. A pace that leaves your target above your resting burn, and that you can keep up, beats a faster one you drop.
This is a general guide, not advice for any one person. If you are under 18, pregnant or breastfeeding, managing a medical condition, or have a history of disordered eating, set calorie targets with a doctor or registered dietitian. The same goes for anyone considering a very-low-calorie diet, which is a treatment for a doctor to supervise.
What these numbers do not show
Both examples are invented to show the arithmetic. They do not predict what the scale does. Your burn is an estimate, and a formula for it is a guess. The 60 to 70 percent share is a typical range, so yours may sit outside it.
Questions people ask
How many calories a day do I cut to lose 2 pounds a week?
The old rule of thumb says about 1,000 a day, from 3,500 calories per pound. It is a rough guide, not a promise. Check the target it gives you against your resting burn, and slow the pace if the target would fall below it.
What if my target would be lower than my resting burn?
Slow the pace until the target is at or above your resting burn. A slower pace is the usual fix. A calorie target should be no lower than your resting burn, whatever pace you wanted.
Is 2 pounds a week safe for everyone?
No. MedlinePlus says losing more than 1 or 2 pounds a week is not safe for most people. Two pounds is the top of the range, not a default. Some people should set targets with a doctor or registered dietitian.
Does the 3,500 calories per pound rule work?
It is a rough starting point. Mayo Clinic says it is not true for everyone, and a published model of body weight says it overstates loss because your burn falls as you get lighter. Re-check your target every few weeks.
A target at the pace you choose
BurnCurve gives a daily calorie target for losing, holding, or gaining, at the pace you choose. It suggests a calorie target no lower than your resting burn. Fast paces carry plain-language cautions. BurnCurve is for general wellness and is not medical advice.