How to Calculate Maintenance Calories

The number of maintenance calories you need daily depends on your age, sex, weight and activity levels, and whether your goal is to lose, gain or maintain weight. Finding your individual needs will help you find the calorie level you need to maintain your weight.

Maintenance calories are, in theory, the level of calories you take in to remain the same weight, and the calculation is based on something called your resting metabolic rate (RMR), and your total daily energy expenditure (TDEE).

Your RMR, according to the American Council on Exercise (ACE), is the caloric energy expended each day when you are only resting. This number doesn't include any activity and accounts for 60 to 80 percent of the calories you burn each day. The number of calories for your individual RMR will depend on your:

• Weight
• Age
• Sex
• Body composition

To get a more accurate picture of how many calories you burn per day, you will also need to guess your activity level. Your physical activity fluctuates the most, and it is harder to determine precisely for obtaining a standard number. The calories burned through physical activity typically accounts for the second-largest amount of calories burned, according to ACE.

If you are highly active and participate in long duration, high intensity or frequent exercise, your percentage of calories burned per day for activity will be much higher than for a sedentary individual.

The third aspect of your TDEE calorie amount is the thermic effect of food. The thermic effect of food is simply the number of calories your body needs to digest and absorb the food you eat. Certain macronutrients and foods require more energy to burn than others. The thermic effect of food is the smallest component of your total daily energy expenditure, according to ACE.

So, your TDEE includes three aspects: your resting metabolic rate, your activity level and the thermic effect of food. Specific scientific formulas can make calculations to assume your total daily energy expenditure. If you consume the number of calories necessary to meet your daily energy expenditure, you are considered to be eating at the level of maintenance calories.

​Read more:​ How to Calculate How Many Calories I Should Eat

There are several calories per day calculator options. A few different formulas have been created for determining the RMR and TDEE. They are based on several different ways of measuring individual needs.

A June 2014 overview in ​Frontiers in Nutrition​, describes the determinants used in most calculations. First, age can change the level of lean body mass you have, and therefore, how many calories you burn at rest. Since lean mass is metabolically active, it burns more calories than fat mass. Lean body mass tends to decline as we age, and less lean mass means less metabolically active tissue, and a lower RMR.

Sex is the second determining factor. Females tend to have higher fat mass and lower metabolic rates than males of the same height and weight. The difference is approximately 5 to 10 percent lower metabolic rate for females, according to the 2014 overview in ​Frontiers in Nutrition​.

Next is body size, with larger individuals having more tissue and higher energy needs than smaller individuals. These energy needs can depend on differences in ethnicity, environment, the body's ability to grow and repair tissue and genetics. Body composition is another critical underlying factor. The amount of fat-free mass an individual has will contribute to their RMR and TDEE.

There are a handful of scientifically developed calculators for determining TDEE or maintenance calories. Note that these equations use the units of weight in kilograms, height in centimeters and age in years. According to the American Council on Exercise, they are:

• Revised Harris-Benedict BMR Equation =
  • Male: (88.4 + 13.4 x weight) + (4.8 x height) – (5.68 x age)
  • Female: (447.6 + 9.25 x weight) + (3.10 x height) – (4.33 x age)
• Mifflin-St.Jeor Equation =
  • Male: 9.99 x weight + 6.25 x height – 4.92 x age + 5
  • Female: 9.99 x weight + 6.25 x height – 4.92 x age – 161
• Katch-McArdle (BMR) = 370 + (21.6 x LBM)
  
  
• Cunningham Equation (RMR) =

500 + (22 x LBM)

Some of these formulations use data that makes them more or less accurate. For example, the Harris-Benedict equation and Mifflin-St. Jeor equation use sex, age, height and weight, making it an easy to use formula, but due to the neglect to account for body composition of lean body mass (LBM), they are not as accurate as the others.

Since not everyone can easily tell their level of lean body mass, the Harris-Benedict formula is widely used for basic calculations, such as the one on the Mayo Clinic's calorie calculator. The benefit of this formula is that it doesn't require you to make guesses or calculations of your lean body mass.

However, using more accurate calculations such as the Katch-McArdle equation will help you find your maintenance calories much more precisely. This difference in precision is especially significant to keep in mind if you are athletic and have a more substantial proportion of lean body mass, according to ACE.

The variance in your TDEE and maintenance calorie level could be as high as 62.3 percent, and the difference in calories recommended could be off by as much as 1,000 calories, according to ACE.

The first step to finding your maintenance calories is to use a formula for finding your RMR. Use one of the previously mentioned formulas to find this number. Once you have your result, you will need to take into account your current physical activity.

There are multipliers used to add physical activity calories to your RMR in order to determine your estimated TDEE. They are as follows, according to ACE:

• Sedentary: little to no exercise with a desk job = multiply by 1.2
• Lightly active: light exercise 1 to 3 times per week = multiply by 1.375
• Moderately active: moderate exercise 3 to 5 times per week = multiply by 1.55
• Very active: hard exercise 6 to 7 times per week = multiply by 1.725
• Extremely active: hard daily exercise and a physical job = multiply by 1.9

You can see that using these formulas will give you varied results. Choose the equation that works best for you based on the information you have. If you are an athletic individual, it may be worth it to find out your LBM for a more accurate result. Remember to adjust the formula if your activity level changes.

Using more than one of these formulas can provide you with an optimal range for maintenance calories. For example, with our sample individual above, he could use the data for the Katch-McArdle and Cunningham equations to determine a range of 2,983 to 3,230 calories per day.

If you currently count calories and are wishing to transition from weight loss to maintenance calories, knowing your TDEE can be helpful. It is not a good idea to continue eating at a caloric deficit if you have reached your goal weight.

Lowering your calories too much can shortchange you of essential nutrients. The USDA 2015-2020 Dietary Guidelines for Americans recommends not consuming less than 1,600 calories per day for women or 2,000 calories per day for men. This is the lowest amount of recommended calories, and a higher amount is necessary for more active individuals.

More active women should eat closer to 2,400 calories, and active men should eat closer to 3,000 calories. Of course, these are broad estimates that do not take into account body weight or body composition, including lean body mass or any other variables that have been discussed previously.

With this in mind, if you have reached the lowest amount of recommended calories, it may be time to switch to the level of maintenance calories.

If you have been previously attempting to gain weight, then figuring out your current TDEE will help you stop at the weight you are currently. Some tweaks may need to be made as your body and metabolism adjust to your new energy level.

​Read more:​ 4 Types of Diets to Avoid if Maintaining Weight Loss is Your Goal

Losing weight may have been the easy part of your journey. Maintaining weight loss seems to be much more tough for most people. According to a January 2018 discussion in ​The Medical Clinics of North America​, a meta-analysis of 29 long-term studies on weight loss revealed that over half of lost weight is regained in two years or less, and 80 percent of weight loss is regained within five years.

The study says that many people may have concluded by now that weight loss is an impossible goal. Indeed, the environment we live in is thought to contribute to obesity and make maintaining weight loss an arduous task.

​Read more:​ How to Lose Weight Fast — The Healthy Way

The study explains that the industrialized food system and the availability of ultra-processed foods have caused an increase in the number of calories consumed by Americans. Moreover, these calories are unhealthy — high in sugars, refined carbohydrates and fats. We've also become more sedentary with desk jobs and less time for physical activity.

For losing and maintaining weight loss, cutting calories through food may not be the best option. A September 2017 study published in ​Perspectives in Psychological Science​ says that hormonal and metabolic adaptations are made even after one year of dieting. These adaptations include appetite increase and energy expenditure decrease. This makes regaining weight very likely if you lose weight through a reduction in calories consumed.

Both the 2018 ​Medical Clinics of North America​ and 2017 ​Perspectives in Psychological Science​ analyses make suggestions based on the evidence gathered:

• Choose high volume, lower calorie, nutritious foods
• Eat foods that contain more protein, fiber and water, such as fruits and vegetables and lean meats
• Especially choose lower fat, higher protein foods
• Prepare meals at home and avoid restaurant-prepared meals and fast food
• Reduce screen time
• Use portion control
• Plan your meals
• Discover non-food related activities and hobbies as coping mechanisms
• Use mindfulness to prevent overeating

Keep in mind the thermic effect of foods when choosing your meals. The ​Perspectives in Psychological Science​ review says that protein digestion accounts for 23 percent of your thermogenesis calories, whereas carbohydrates account for 6 percent and fat is 1 percent. Choosing high protein meals will cause an increase in calories burned through thermogenesis and also increase meal satiety.

​Read more:​ The Best Tips for Every Stage of Your Weight Loss Journey