What "maintenance calories" really means, and how to measure yours
Maintenance calories are the calories your body uses in a typical day: what you'd need to eat for your weight to stay where it is. Formulas can estimate it, but the only way to know your own is to measure it, from what you eat and how your weight moves over a few weeks.
Key takeaways
- Maintenance calories are your total daily energy use: your body at rest, plus movement, plus digesting food.
- Formulas such as Mifflin-St Jeor estimate the resting part from weight, height, age and sex; an activity factor adds the rest.
- Formulas are averages, and your own maintenance can differ from them.
- Measured maintenance comes from a few weeks of honest logging alongside a weight trend.
- It's a measurement, not a target.
What maintenance calories are
Your body uses energy all day. Most of it goes to keeping you alive at rest: breathing, circulation, keeping warm, the work of every organ. That's your resting energy use, often called BMR (basal metabolic rate) or REE (resting energy expenditure). On top of that comes everything you do, from walking to the bus to exercise, and a smaller amount used to digest food.
Add those together for a typical day and you get your total energy use, which is what people mean by maintenance calories. If you eat about that many calories on average, your weight stays about the same. For what typical Indian dishes add, see Calories in Indian food.
Estimating it with a formula
A widely used formula for resting energy use is the Mifflin-St Jeor equation, published in the American Journal of Clinical Nutrition in 1990 from measurements of 498 adults:
- Men: 10 x weight in kg + 6.25 x height in cm - 5 x age + 5
- Women: 10 x weight in kg + 6.25 x height in cm - 5 x age - 161
To get from resting energy to a whole day, it's multiplied by a physical activity level (PAL). The FAO, WHO and UNU's report on human energy requirements classes a sedentary or lightly active lifestyle at a PAL of 1.40 to 1.69, an active or moderately active one at 1.70 to 1.99, and a vigorously active one at 2.00 to 2.40.
A worked example
Take a woman aged 30, 160 cm tall and 60 kg: 10 x 60 + 6.25 x 160 - 5 x 30 - 161 = 1,289 calories at rest. With a desk job and little other movement, a PAL of 1.40 to 1.69 puts her maintenance at roughly 1,800 to 2,180 calories a day.
For a man aged 30, 175 cm and 75 kg: 10 x 75 + 6.25 x 175 - 5 x 30 + 5 = 1,699 calories at rest, and roughly 2,380 to 2,870 a day at the same activity level.
Why a formula is only a starting point
Formulas describe averages. In the original study, weight, height, age and sex together explained about 71% of the differences in measured resting energy use between people. The rest came from things the formula can't see, such as how much of your weight is muscle.
The activity factor is a wider guess still. Two people with desk jobs can move very differently through the day. So a formula gets you into the right area, and for some people it's well off in either direction.
Measuring your own
The way to know your own maintenance is to measure it. If you log what you eat honestly and your weight trend stays flat, your average intake is about your maintenance. If the trend drifts up or down, your maintenance is below or above what you've been eating. Turning the speed of that drift into calories needs a few weeks of data, and it's the arithmetic Slate Plus does for you, described below.
- Log everything you eat and drink for at least three weeks, as consistently as you can. Rough numbers are fine if you count the same way each day, though if you always undercount, the measured number comes out low by about the same amount. The home cooking guide covers counting dal, roti and oil.
- Weigh yourself a few times a week, at the same time of day.
- Look at the trend, not single weigh-ins. Water, salt and meal timing move the scale from one day to the next; a smoothed trend line shows the direction.
- Compare your average daily intake with the direction of the trend.
Weight also takes a long time to settle after a lasting change in eating. A 2011 analysis in The Lancet put the half-time of the body's response at about a year. So a few weeks of trend shows the direction you're moving in, not where your weight will end up.
What maintenance is not
Maintenance describes what your body has been doing. What you do with that number is up to you.
If you have a medical condition, are pregnant or breastfeeding, or are under 18, energy needs work differently and the formulas above don't apply in the same way. Talk to a doctor or a registered dietitian.
Measured maintenance in Slate
Slate shows your BMR and sedentary baseline for free, from your age, sex, height and weight, and updates them as your weight trend changes. With Slate Plus, after about three weeks of logging and a few weigh-ins, Slate works out how many calories your body has actually been using each day from what you logged and how your weight trend moved. It shows it as a measurement and doesn't turn it into a goal or a suggestion.
Questions people ask
What are maintenance calories?
The calories your body uses in a typical day, at rest and moving. Eating about that many on average keeps your weight about the same.
How do I calculate my maintenance calories?
A formula such as Mifflin-St Jeor estimates your resting energy use, and multiplying by an activity level (1.40 to 1.69 for a sedentary or light lifestyle, from FAO, WHO and UNU) gives a starting estimate. Measuring it from a few weeks of logging and a weight trend is more accurate.
Is BMR the same as maintenance?
No. BMR is what your body uses at rest. Maintenance adds movement and digestion on top, so it's higher.