How Many Calories Should Women Eat?

I get asked a common question from women with all body sizes and activities levels: "How many calories should I be eating each day?"  Now, this is a loaded question because our calorie needs vary so greatly based on our individual hormonal balance, muscle mass, activity level, and even the types of food we consume. The simple answer is: Eat as much as you are hungry for. In a perfect world that would work for everyone! This is not a perfect world.

This is a common source of confusion for men and women. There is a lot of misinformation available online and in the community, and our diet culture perpetuates low calorie diets for weight loss which work, but only temporarily. I am going to address the question of how many calories should women eat each day to the best of my ability without burying you with detail.

Disclaimer: This is my opinion as a dietitian but does not constitute as medical advice and may not apply to women with certain health conditions.

Energy Expenditure 101

If you already know the basics of what makes up your daily energy requirements then please feel free to skip to the next section. For those who could use a quick brush up on the components of energy expenditure then read on.

What is energy expenditure?

Energy expenditure is the amount of energy (food) needed to support daily activities. Obviously, daily activities include moving, working and exercising, but a large amount of energy is also needed to sustain normal biological functions which allow you to be a living being. Our daily energy expenditure also includes the calories needed to breath, circulate blood, digest food and produce hormones. Total Energy Expenditure (TEE) is composed of Basal Energy Expenditure, Thermic Effect of Food (TEF) and Physical Activity.

Basal Energy Expenditure (BEE)

The best way to increase your BEE is to build muscle. Muscle is amazing because it burns energy at rest, so the more muscle mass you carry the more calories you will need to consume to maintain your weight.

BEE is the energy your body requires in a resting state. This includes every process your body does while you are completely at rest, the energy you would need if you were to stay completely still and not eat or drink anything all day. Basal metabolic rate must be measured after 8 hours of sleep and 12 hours of fasting. BEE is the largest contributor to your TEE accounting for anywhere from 45-70% of your total caloric expenditure. The best way to increase your BEE is to build muscle. Muscle is amazing because it burns energy at rest, so the more muscle mass you carry the more calories you will need to consume to maintain your weight.

Physical Activity

This one is a no-brainer. We all know that if we move more we will burn more calories. Our physical activity includes structured exercise, but also Non-Exercise Activity Thermogenesis (NEAT). NEAT involves activities like taking the stairs, doing yard work, standing, or fidgeting. These activities are not thought of as exercise but contribute to your daily energy expenditure. Physical activity can account for 20% (sedentary individuals) to 50% (athletes) of your daily energy needs, but usually ranges from 30%-40%.

Ways to increase your physical activity without spending more time in the gym:

• Always take the stairs
• Pace while on the phone
• Stand while you work
• Listen to music that makes you want to dance
• Play with your pets
• Walk to the store if you live in the city

Thermic Effect of Food (TEF)

The TEF generally accounts for 8-10% of your daily expenditure. This can influenced by the types of foods you choose to eat and the macronutrient makeup. Foods that are less processed will be harder for your body to breakdown and therefore require more energy to complete digestion.

Eating burns calories. How great is that? Our digestion processes are complicated, and highly intricate. There are many steps required to turn the food we eat into usable building blocks within our cells. The TEF generally accounts for 8-10% of your daily expenditure. This can influenced by the types of foods you choose to eat and the macronutrient makeup. Foods that are less processed will be harder for your body to breakdown and therefore require more energy to complete digestion. Macronutrients also require differing amounts of energy to breakdown. Protein requires the most energy, carbohydrates are second, while fats require the least amount of energy to digest. Please note that fats are still incredibly satiating, are necessary for hormone production and are vital components of brain and cellular tissue. They remain an very important component of a healthy diet.

Estimating Your Calorie Needs: Where to start?

1.) Calculate your BEE (or BMR)

The first step towards figuring out the amount of calories you need per day is to calculate your BEE. Since we are not in a metabolic lab, this, of course, will be an estimation but it can be extremely helpful. As a dietitian, we  use the Mifflin-St Joer equation to calculate BMR (Basal Metabolic Rate - the estimation of BEE). This equation provides a reliable estimation and a good starting point towards understanding your calorie needs.

Mifflin-St Joer Equation for Women

BMR = 10 × weight(kg) + 6.25 × height(cm) - 5 × age(y) - 161

You can use this site to input your data if you don't feel like busting out your TI-83.  Remember to select BMR for activity level.

This number is the amount of calories you will burn each day without eating or moving. YOU SHOULD NEVER RESTRICT YOUR CALORIES TO YOUR BMR. Even if you are trying to lose weight it is wise to keep your caloric intake above this leveL because your body needs this number of calories to function effectively and efficiently. Restricting your calorie intake to your BMR will cause cravings, over/undereating cycles, nutrient deficiencies, weight cycling, decreased metabolism and unsustainable weight loss.

Some of you are going to shake your head at this after you calculate your BMR (which usually ranges from about 1100-2000 calories depending on your body size and stature). I've been there. There's been a period in my life when I would restrict my calories to 1200 (I am 5'8 and very active - sustainable? nope). Sure I lost weight, but it was impossible for my body to sustain this weight loss because at this calorie level my body was unable to maintain normal metabolic rate (decreasing weight, muscle mass and TEF will ALWAYS decrease your metabolic rate). After I realized this wasn't a long term solutotion I upped my caloric intake to 1600 which seemed totally reasonable to me. At this level (which is pretty close to my BMR) I gained all the weight I had lost right back within the first 8 months. Unfortunately, I was still starving. I gained weight while under eating  How unfair is that? I had done metabolic damage, yet I still wasn't giving my body the calories it needed to function properly. I was caught in a binging and purging cycle because I was perpetually under eating and over exercising. I blamed it on lack of self control but really I just needed to eat more. I thought to myself, if I gained 30 pounds in less than a year eating 1600 calories/day I certainly could not eat more than that or my weight would be out of control. It took me years to come to terms that 1600 calories was not appropriate for a women my height. Today I eat 2300-2600 calories every day and I weigh a couple pounds more than I did in high school before I developed an eating disorder and have a heck of a lot more muscle mass. I eat until I am full at every meal, I never go to bed hungry, I overeat sometimes, I eat what I want and I don't obsess about it. If you are eating dangerously close to your BMR try eating 100 more calories every 2 weeks until you are eating an amount where you feel satisfied and satiated.

2.) BMR x Activity Factor

Sedentary = BMR x 1.2 (little or no exercise, desk job)
Lightly active = BMR x 1.375 (light exercise/ sports 1-3 days/week)
Moderately active = BMR x 1.55 (moderate exercise/ sports 6-7 days/week)
Very active = BMR x 1.725 (hard exercise every day, or exercising twice/day)
Extra active = BMR x 1.9 (hard exercise 2 or more times per day, or training for
marathon, or triathlon, etc.)

Your BMR x Activity Factor = Calories needed every day of the week in order to maintain your current weight.

If you are trying to lose weight I would suggest reducing your daily intake by 250 calories per day keeping in mind that you always want to keep your intake above your BMR.

A quick trick for estimating energy needs:

Weight Loss = 12-13 calories per pound of body weight
Maintenance = 15-16 calories per pound of body weight
Weight Gain = 18-19 calories per pound of body weight

When Should You Count Calories?

Counting calories is not always a healthy habit. Counting calories can perpetuate an unhealthy obsession about food and body image. If you are counting calories for months (or years) you may need to take a step back and evaluate why you are counting calories, assess your relationship with food and take a different approach towards weight maintenance.

When is counting calories helpful?

• • • Transitioning from prolonged periods of bingeing and restricting. Counting calories can be helpful when you have lost touch with your innate hunger and fullness cues. When you begin to adopt normal eating patterns after struggling with binge cycling, some people find it helpful to track calories for several weeks to aid in allowing the nervous and digestive system to adapt to accepting an appropriate amount of food without under or over eating. This is not meant to be something you continue indefinitely. Once you have eaten reasonably within your calorie range for 1-2 weeks, it would be appropriate to transition to a more intuitive eating style where you focus on eating whatever your hungry for and really pay attention to your satiation and motivation for eating.
    • To ensure you are eating enough calories. In specific situations you might find that you need to assess your caloric intake in order to prioritize your health or meet your athletic or performance based goals. Women who are coming off of hormonal birth control, struggling with hypothalmic ammenorhea, or dealing thyroid dysregulation may need focus on adequate food intake in order to support hormonal balance, improve thyroid function or begin menstruating again. Counting calories to ensure that you are not hindering your fertility is absolutely a valid reason to track your intake. Those who have specific goals relating to athletic performance, endurance activities, or gaining muscle mass may also need to track calories and/or macros occasionally for several days to ensure you are eating to perform.
    • After a prolonged period of unintentional weight loss or gain. Alright friends, I know this is hard to swallow but you are going to gain 5-10 pounds for various reasons throughout the month. Your weight can fluctuate because of your hydration status, sodium intake, carbohydrate intake, the time in your menstrual cycle, changes in muscle mass, inflammation, how hard your are training, and countless other reasons. This is all the more reason to ditch the scale. If you experience weight gain or loss that sticks around for several weeks, changes in  caloric intake could be the culprit. Track your calories to ensure you are eating reasonably within your TEE for several days and then move on with your life.

  I hope this information was helpful. Remember that the best way to maintain a healthy weight is to eat whole foods, honor your cravings, and focus on being present and mindful during your mealtimes. No calorie estimator is perfect so it is important to listen to your unique body and choose foods that feel nourishing to you. The best indicator that you are over or under eating is sustained changes in your body size. Your health status is fluid, and it will fluctuate. Your body size will also. Continuously working to make sustainable choices that promote both physical and emotional wellness will help you achieve long term health and a body size that is right for you. Cheers!

  

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