Key Takeaways:
- Use the Mifflin-St Jeor equation to calculate your caloric needs and adjust your calorie intake based on your activity level. (1)
- Whether you’re aiming for weight loss, maintenance, or gain, adjust your caloric intake accordingly. A good rule of thumb is to subtract up to 500 calories for a caloric deficit and to add up to 500 calories to create a surplus for weight gain. (2)
- Ensure your calories come from a healthy balance of proteins, fats, and carbohydrates. A general guideline is to aim for a ratio of 40% carbs, 30% protein, and 30% fats. (3) This will help you get the nutrients your body and brain need to operate at peak performance while also helping you feel full for longer. (3)
- Make gradual changes. Too many changes at once can feel stressful and overwhelming. Making gradual, sustainable changes is helpful for achieving your goals. (4)
- While the premise of the CICO diet is simple and logical, everyone’s body is different. Factors like your metabolism, genes, age, and more play a role in weight management. Use MyFitnessPal to optimize your caloric intake and be gentle with yourself, as calorie counting is not a perfect science. (2)
If your health and wellness goals include losing, gaining, or maintaining your weight, it’s helpful to learn how to calculate your caloric needs. Knowing how many calories you need can help guide your food and activity choices to reach your goals. This is the whole idea behind the CICO diet, which stands for Calories In Calories Out.
The logic behind the CICO diet is that once you know your caloric needs, you can add, subtract, or meet them to gain, lose, or maintain weight.
Keep reading for a step-by-step guide to calculating your caloric needs using the Mifflin-St Jeor equation. Plus, you’ll learn how to work with that number once you know it.
Step 1: Calculate Your Basal Metabolic Rate (BMR)
It all starts with the basal metabolic rate (BMR). That’s the number of calories your body burns just to stay alive. (1) Even if you stayed in bed all day, your body would still require energy (aka calories) to breathe, pump blood, produce cells and hormones, and so on.
One of the most reliable ways to calculate BMR is by using the Mifflin-St Jeor equation, which factors in your weight, height, age, and gender. (1, 5)
By plugging your own numbers into this formula, you can get a personalized estimate of how many calories your body burns at rest. I say “estimate” because while this is one of the most accurate ways to calculate your BMR, it’s not a perfect science. (More on this later.)
Let’s take an example and calculate this together. For instance, if you’re a 35-year-old woman who’s 5’4’’ and weighs 165 pounds, you’d first need to calculate your height and weight in centimeters and kilograms.
- Height in centimeters = height in inches x 2.54 or 64 x 2.54 = 162.56
- Weight in kilograms = weight in pounds ÷ 2.2 or 165 ÷ 2.2 = 75
Now, let’s plug these numbers into the BMR equation.
- BMR = (10 × 75) + (6.25 × 162.56) – (5 × 35) – 161
- BMR = 750 + 1016 – 175 – 161
- BMR ≈ 1,430 calories/day
This means your body requires about 1,430 calories each day just to maintain essential functions. However, since you don’t spend all day lying down, you need to adjust your energy needs based on how active you are. (If you’d rather skip the math, you can easily calculate your BMR here.)
Step 2: Adjust BMR Based on Your Activity Level
Now that you know your BMR, you can factor in your activity level to get a more accurate picture of how many calories you really need each day. That’s your total daily energy expenditure (TDEE). TDEE considers your daily movement and adjusts your caloric needs accordingly. (1) To estimate your TDEE, you can use the following activity level multipliers:
Sedentary (little to no exercise)
Use this activity level multiplier if you get minimal activity or movement throughout the day–say, because you drive to work and have a desk job. (1)
Activity multiplier: BMR × 1.2
Lightly active (exercise 1-3 days per week)
This is when you perform some activity–such as going for a walk–up to three days a week. (1)
Activity multiplier: BMR × 1.375
Moderately active (exercise 3-5 days per week)
Let’s say you walk a lot in your day-to-day life and exercise most days; you’d be considered moderately active. (1)
Activity multiplier: BMR × 1.55
Very active (exercise 6-7 days per week)
If you’re engaging in any purposeful exercise–like hopping on the elliptical –most days, or you have a physical job, you’d be considered very active. (1)
Activity multiplier: BMR × 1.725
Super active (hard exercise or physical job)
You’d be considered super active if you pushed yourself hard when you work out–say in spin class–or if you have an intensely physical job. (1)
Activity multiplier: BMR × 1.9
Getting back to our example, if you exercise four times per week, your activity multiplier would be BMR × 1.55. Your BMR was 1,430 calories, so the equation looks like this.(1)
TDEE = 1,430 × 1.55 = 2,216.50 calories/day
This means that for you to maintain your current weight, you’d need around 2,215 calories per day. Now, we’ll adjust this number based on your goals.
Step 3: Set Your Goal: Weight Loss, Maintenance, or Gain
Here’s where you’ll learn how to calculate your caloric needs depending on your personal goal.
For weight loss:
The logic behind the CICO diet is that a pound is roughly equivalent to 3,500 calories. (6) Therefore, to lose weight, you’d subtract 250 to 500 calories from your TDEE.
Using our example TDEE of 2,215, you can cut your intake by 500 calories, aiming for a daily intake of around 1,715 calories. This should lead to a gradual, sustainable weight loss of about 1 pound per week.
Remember that gradual changes are helpful because they don’t feel overwhelming. Also, keep in mind again that while calorie counting is a helpful tool for weight loss, it isn’t a precise science. You may lose more or less weight than predicted after calculating your personal caloric needs for weight loss.
For weight gain:
If you’re trying to gain muscle or increase your weight, you’ll need to consume more calories than your TDEE. Your caloric needs for weight gain can increase by about 500 calories per day, bringing your total to around 2,715 calories.
A calorie counting tool will come in handy as you focus on adding calories for weight gain. MyFitnessPal can also make it easier to ensure you’re adding calories from nutritious sources.
For maintenance:
For weight maintenance, aim to match your calorie intake to your TDEE. In our example, that would mean consuming about 2,215 calories per day.
Whatever your goal, making small, gradual adjustments is the best way to ensure long-term success. Extreme caloric deficits or surpluses can be difficult to sustain and may negatively impact your health. A calorie counting app, like MyFitnessPal, can help you follow the CICO diet for weight gain, loss, or maintenance.
About the Experts:
Samantha Cassetty, MS, RD, is a nationally recognized food and nutrition expert, media personality, nutrition consultant, and author. Cassetty is a former nutrition director for Good Housekeeping and the co-author of the book Sugar Shock.
Daisy Mercer, RD, is a Food Data Curator at MyFitnessPal. She graduated with her bachelors of Food Science and Dietetics from Colorado State University and completed her dietetic internship with the VA San Diego Healthcare system.
Macronutrient Balance: Optimizing Your Caloric Intake
The CICO diet can help you manage your caloric intake, but macronutrient balance helps you optimize your nutrition.
The three macronutrients are proteins, fats, and carbohydrates. The right balance helps you fuel your body properly for specific goals, whether that’s losing weight, building muscle, or weight maintenance. (You can determine a personal macro goal using this free macro calculator.)
Protein:
Protein is essential for maintaining muscle strength and mass. (7) Protein is also associated with increased satiety, helping you feel full for longer stretches after meals. (1) Getting enough protein while you’re losing weight will help you preserve muscle mass and improve satiety while you’re in a caloric deficit. (6)
Fats:
Fats not only help you absorb nutrients, but they slow the rate at which food is digested and metabolized. That means, like protein, fat can help you feel fuller longer. (8) A beneficial macronutrient balance includes about 30% of your daily caloric needs from heart-healthy fats, like those found in avocados, nuts, seeds, and extra virgin olive oil. (3)
Carbohydrates:
Carbs are often maligned–particularly among those trying to lose weight. However, carbs are your body and brain’s main energy source, and your muscles need carbs to fuel physical activity. (9) The net-net is that carbs are a vital part of your macronutrient balance. Typically, 40% of your daily caloric needs should come from carbohydrates.(3)
Of course, these are general guidelines, and some people prefer to balance their macronutrient intake differently.
Calorie Counting Isn’t an Exact Science: Other Factors to Consider
While calorie counting can be a helpful tool for managing your weight, there are other things that influence your body’s ability to lose or gain weight.
That’s why it’s important to be gentle with yourself as you embark on a weight management journey. While calorie tracking is helpful, there’s still some trial and error to the process.
Metabolism:
You don’t have as much control over your metabolism as you think. Everyone’s metabolism is unique, and age, genetics, and gender influence your metabolic rate.(7) Of course, your activity levels–how active or inactive you are–is a factor of your metabolic rate that you can control. (More on this below.)
Hormones:
Hormones, particularly those related to thyroid function, can affect weight gain or loss. Hormones related to menopause may also influence your ability to lose weight. Talk to your doctor if you suspect hormonal imbalances are making it harder for you to manage your weight. (7)
If you’ve lost weight in the past, appetite-regulating hormones may make it more difficult to maintain this weight loss because these hormones make you hungrier. (10)
Exercise and muscle mass:
In addition to improving your health and burning some calories, exercise–particularly strength training– helps you build more muscle tissue. (5) Muscle burns slightly more calories than fat, even at rest.(5) So, the more muscle mass you have, the higher your metabolism and caloric needs.
The Bottom Line: Understanding and Adjusting Your Caloric Needs
To optimize your health and reach your goals, start by calculating your caloric needs using the Mifflin-St Jeor equation, adjusting for your personal activity level. Then you can start counting calories for weight loss, maintenance, or gain. (MyFitnessPal can make this so much easier!)
While this is a good start, it’s also helpful to consider your macronutrient balance since some calories are more filling and nutritious than others.
Remember, this process is highly individual, and other factors like genes, hormones, and muscle mass also play a role. With gradual, sustainable changes and a balanced approach to calories and macronutrients, you can make progress toward your personal goals.
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