What are ‘maintenance calories’ or ‘calorie maintenance’?

Most people start thinking about the calories in food and drink when they’re looking to lose weight. 

That’s because, to achieve weight-loss, the number of calories you consume must be lower than the number of calories you expend or ‘burn’. In simple terms, calories in must be less than calories out.

The total number of calories you burn on a daily basis is known as your maintenance calories. So-called because if you consume no more and no less than your maintenance calories you will maintain the same weight – in other words, your weight will stay the same.

You can see, therefore, why calculating maintenance calories is a critical task if you want to know how many calories you can eat to stay as you are, to lose body fat or, indeed, to gain muscle mass (for which the best results are achieved by eating more than your calorie maintenance, combined with an effective resistance training programme).

If you eat below your maintenance calories you will lose weight. If you consume above calorie maintenance you will gain weight. 

What factors affect your maintenance calories?

Everyone’s maintenance calories are different and are affected by two main factors.

The first of these is your lean body mass (your muscles and major organs). So someone who has a lot of muscle mass (like a body builder) will, even at rest, before they even start to move or do exercise, burn more calories than somebody with very low muscle mass. (The energy/calories your body burns whilst at rest is known as your ‘resting metabolic rate’, or RMR.)

If you are someone who is sedentary and doesn’t activate your muscle with exercise, it is your internal organs (required to keep you alive and maintain normal bodily functions) that will account for as much as 70% of your calorie expenditure.

The second contributing factor to your maintenance calories is the amount of exercise and physical activity you do. That’s not just ‘scheduled’ or ‘formal’ exercise like playing a game of netball or going to the gym, it’s also the activities and movements you make you don’t even think about. For example, if you walk a lot (have a high step-count), do a lot of housework or gardening, and live in a house with stairs, you will burn more calories than if these were not the case. Even less conscious than walking are things like fidgeting. Someone who “can’t sit still” will have a higher calorie maintenance than someone who is “laid back”.

This ‘non-formal’ activity is known as NEAT – non-exercise activity thermogenesis – and can account for a ten-fold (yes, ten-times!) difference in fat-gain among individuals fed the same surplus above their maintenance calories over a fixed period.

How do you calculate maintenance calories?

There are two main ways to calculate maintenance calories. The first is to use a maintenance calorie calculator. The second is to do it empirically and observe what happens in real life. Let’s explain those in more detail.

Using a maintenance calories calculator

There are many maintenance calorie calculators (like this one) on UK and international websites that will attempt to work out your caloric maintenance. But without knowing your lean body mass, these online calculators are forced to use a formula that assumes an ‘average’ or ‘typical’ level of muscle for your age and sex.

Because organs and muscle are big contributors to your maintenance calories, a DEXA body scan, which establishes your lean mass accurately, means you can use a maintenance calculator built on a better formula, like Bodyscan’s here. Without a DEXA scan, you won’t have the inputs (bone, fat and lean mass) to get this more accurate maintenance calories result.

But all calorie calculators, even ones built around the results from a DEXA scan, require a certain leap of faith (or trust) when it comes to the level of activity you claim to do. In Bodyscan’s experience, the vast majority of people over-estimate how active they are, which will give them a higher number of calories for maintenance than is the case. Remember, there are 168 hours in a week, so if going to the gym three hours a week is your only activity, you are sedentary!

If you watch this video clip from Bodyscan, you can see a real-life example why using a maintenance calorie calculator without a DEXA scan can lead to bad results and a lot of frustration.

Working out your maintenance calories by real-life observation

Even when a calculator is ‘on the money’ (and Bodyscan’s, teamed with our consultants’ experience, almost always is), maintenance calorie calculators require you, necessarily, to know how many calories you’re consuming in order to meet the maintenance (or suggested deficit) target.

If you don’t want to count calories, then a far simpler way is to observe your weight. If your weight remains stable then you are, by definition, eating maintenance calories! If your weight is falling, then you are below maintenance.

Of course, without calorie counting, you will not know an actual number for your calorie maintenance but you will know that, whatever the number, if you reduce your consumption, you will be in a deficit and your weight will fall.

Using DEXA for calculating maintenance calories

In our experience, a calorie calculator that uses DEXA scan inputs gives very reliable results, and this has been validated by Bodyscan customers who have assiduously measured and weighed their food, counted calories and achieved the results we predicted they would.

But whichever calculator you use to arrive at a number for your maintenance calories, always treat it as a guide and see what results it gives in real life. Many people “live their life” by the number and doggedly treat it as sacrosanct even though, after months of sticking to what they believe is a deficit, their weight doesn’t change. If your weight does not fall then you are not eating below calorie maintenance!