The 3 Cs of Weight Loss Series: Calories
Calories Defined
In terms of nutrition, a calorie is a unit of measure that indicates how much energy a food contains. According to Anthony Komaroff, MD, “Calories are units representing the ability of food to be converted by the body into energy. All food contains calories, and we need a certain amount of calories each day.[1]” There are 3,500 calories in 1 pound of fat.
How Many Calories Does Your Body Burn?
Your body naturally burns energy (calories) on its own. This number is called your resting metabolic rate, and will be incorporated into your total daily energy burned. The total daily energy burned is also your weight maintenance threshold. Knowing the amount of energy your body burns in a day is a fundamental step in structuring a sound eating plan.
Example: You’re a 49 year young, 5’2” woman who weighs 140 pounds. Your resting metabolic rate (RMR) is 1,216 calories per day (calculated using Mifflin-St. Jeor Equation)[2]. You participate in intense work outs 6 days a week, burning approximately 900 calories per day.
1. Find your resting metabolic rate (RMR).
2. Calculate your total daily energy expended.
• Find your activity level in the chart below
• Multiply your resting metabolic rate (RMR) by the corresponding number in the last column.
| Activity Level | Description | Multiplier |
|---|---|---|
| Sedentary | Little to no exercise | 1.2 |
| Lightly Active | Light exercise or sports 1-3 days per week | 1.375 |
| Moderately Active | Moderate exercise or sports 3–5 days per week | 1.55 |
| Very Active | Intense exercise or sports 6–7 days per week | 1.725 |
| Extremely Active | Intense daily exercise or sports; or physically demanding job | 1.9 |
Example (cont’d):
| RMR | 1,216 calories per day |
| Very Active | x1.725 (intense exercise 6 days per week) |
| TOTAL | 2,098 total daily energy expended |
If you were to consume approximately 2,100 calories per day, your body would be in caloric balance[3]. This is your weight maintenance threshold, the total number of calories you would need to eat in order to maintain your current weight.
Define Your Deficit
Consuming fewer than 2,100 calories per day, regardless of the amount, will create a caloric deficit. In order to shed 1 to 2 pounds per week, you need to consume 500 to 1,000 calories fewer than the number of calories needed to maintain your weight.
If you reduce your total daily caloric intake by 500 calories per day, you would lose 1
pound per week:
pound per week:
2,100 calories per day (maintenance)
– 500 calories per day
1,600 calories per day (weight loss)
– 500 calories per day
1,600 calories per day (weight loss)
Caloric deficits are only advised if you consume at least 1,200 calories a day for women, or 1,500 calories per day for men[4]. Eating too few calories can actually slows your metabolism, as this is part of your body’s built-in mechanism to help keep you from starving. It can also deprive your body of necessary nutrients[4].
Tip: Get the most out of your calories
Cutting 500 to 1,000 calories from your daily diet may be a significant portion of what you’re used to eating. Whether you’re cutting calories or just looking to tweak your current eating plan, make sure the calories you consume are packed with the nutrients your body needs.
Foods higher in fiber have less impact on your blood sugar levels, and keep you feeling fuller longer.
To get more information on customizing an eating plan especially for you, see
References:
[1] Harvard T.H. Chan School of Public Health. (n.d.). Understanding empty calories. Retrieved February 1, 2020, from https://www.health.harvard.edu/staying-healthy/understanding-empty-calories [2] Kelly, M. P. (n.d.). Resting Metabolic Rate: Best Ways to Measure It-And Raise It, Too. Retrieved January 25, 2020, from https://www.acefitness.org/certifiednewsarticle/2882/resting-metabolic-rate-best-ways-to-measure-it-and/ [3] Finding a Balance. (2018, September 18). Retrieved January 3, 2020, from https://www.cdc.gov/healthyweight/calories/ [4] Harvard Health Publishing. (n.d.). Calorie counting made easy. Retrieved February 3, 2020, from https://www.health.harvard.edu/staying-healthy/calorie-counting-made-easy
