**Calories**

Acronyms and Definitions

- BEE - Basal Energy Expenditure, or amount of energy the body uses at rest
- MET - Metabolic Equivalent - equal to 1 calorie/kilogram of body weight/ hour
- Calories versus kilocalories - In the context of food, these terms are interchangeable
- kg - kilogram
- 1 kilogram is equal to 2.2 pounds. To convert pounds to kilograms, divide pounds by 2.2
- FDA - U.S. Food and Drug Admin
- BMI -
**Body Mass Index** - USDA - United States Dept of Agriculture

**CALORIES AND BODY WEIGHT**

- A person's weight is a product of the amount of calories they consume minus the amount of calories they expend
**Calories consumed from food - calories burned through activity = net gain/loss of calories**- If a person consumes more calories than they expend, they will have a net gain of calories, and the body will store these calories as fat
- If a person consumes fewer calories than they expend, then the body must utilize stored energy (fat) in order to meet energy demands
**NOTE:**In the context of food, "kilocalories" and "calories" mean the same thing and are interchangeable

**CALORIE EXPENDITURE**

__In general, there are three components to a person's daily caloric requirement:____Basal Energy Expenditure__- Amount of energy required for the body to sustain normal life processes - breathing, tissue metabolism, etc.
- This is dependent on a person's height, weight, age, and sex
__Physical Activity__- Calories burned during activities
- Highly variable between individuals
__Thermic effect of food__- Energy expended by the body to process food for storage and use
- Accounts for about 8 - 10% of daily energy expenditure [1]

**CALCULATING DAILY CALORIC REQUIREMENTS**

__DETAILED METHOD FOR CALCULATING DAILY CALORIC REQUIREMENTS____STEP 1 - Calculate the Basal Energy Expenditure (BEE)__- Basal Energy Expenditure (BEE) is calculated using the Harris-Benedict equation
__Males__BEE (calories/day) = 66 + (6.23 X weight in pounds) + (12.7 X height in inches) - (6.76 X age in years)**English:**BEE(calories/day) = 66 + (13.8 X weight in kg) + (5.0 X height in cm) - (6.8 X age in years)**Metric:**__Females__BEE (calories/day) =655 + (4.35 X weight in pounds) + (4.7 X height in inches) - (4.7 X age in years)**English:**BEE(calories/day) = 655 + (9.5 X weight in kg) + (1.9 X height in cm) - (4.7 X age in years)**Metric:**__Example:__- Patient A is a male, 183 pounds, 73 inches tall, and 39 years old
- BEE = 66 + (6.23 X 183) + (12.7 X 73) - (6.76 X 39)
- BEE = 66 + (1140) + (927) - (264)
- BEE = 1869 calories a day
__STEP 2 - Multiply the BEE by a factor of 1.2 to get the lowest sedentary metabolic rate__- This gives the minimal amount of calories a sedentary person will use in a day doing close to nothing
Patient A - 1869 calories/d X 1.2 = 2243 calories required to be sedentary all day**Example:**__STEP 3 - Calculate calories burned during various activities__- The
*Compendium of Physical Activities*was developed by scientists to measure the amount of energy that is expended during various activities - Values for energy expenditure are expressed in METs or "Metabolic Equivalent of Task"
- One MET is defined as 1 calorie/kg of body weight/hour. It is equivalent to the amount of energy a person would expend sitting quietly and doing nothing.
**NOTE:**While the basal energy expenditure (BEE) can be calculated using the value of one MET, we prefer to use the Harris-Benedict equation because it is more precise.- The
*Compendium of Physical Activities*has an extensive list of physical activities and their MET values. It is available online at the link below. **To calculate the amount of calories burned during an activity, follow these steps:**- 1. Find the MET value for the activity on the list
- 2. Subtract 1 from the MET value of the activity
***** - (NOTE: If you are only calculating the calories burned during the activity, you may wish to leave the 1 MET and disregard BEE (Step 1) calculated above)
- 3. Take the number of minutes you did the activity and convert it to hours
- 4. Multiply the number of hours by the MET value and your weight in kg
- 5. Add this amount of calories to your BEE from STEP 2
**Example:**__Patient weighs 70kg and walked for 30 minutes__- 1. from MET list - walking 2.5 mph, level, firm surface - MET 3.0
- 2. MET 3.0 - 1.0 = 2.0
- 3. 45 minutes / 60 minutes = 0.75 hours
- 4. 0.75 hours X 2.0 METS (calories/kg/hr) X 70kg = 105 calories burned
- 5. Add 105 calories to the value from STEP 2
*****One MET is subtracted in this step because the MET values in the compendium include basal calories that are burned during the exercise (equal to one MET). We used the Harris-Benedict equation to calculate basal calories and need to adjust for this.__Important points about METs__- The compendium is quite extensive and just about any activity can be found
- For weight loss purposes, do not get hung up on calculating calories burned for every little activity you perform
- Only calculate values for major activities and planned exercise (ex. biking, walking, jogging)
- MET values are not perfect and studies have shown they can sometimes underestimate calories burned during activities (In terms of weight loss, this can be advantageous) [3,4]
__SIMPLE METHOD__- A simpler, less exact method of calculating daily calorie expenditure uses the Harris-Benedict equation for BEE, and then multiplies this number by a factor based on a person's estimated activity level
- An interactive calculator is available at the USDA website -
**USDA calorie estimator** - Estimated activity levels are defined on the website

**CALORIE DEFICIT FOR WEIGHT LOSS**

__CALORIE DEFICIT__- In order to lose weight, a person must consume a daily deficit of calories
- In general, the following is true:
__In overweight adults with BMI > 27:__- 500 calorie deficit a day for 7 days will produce one pound of weight loss on average
- A 1000 calorie deficit a day for 7 days will produce 2 pounds of weight loss on average, and so on
- As body weight decreases, further weight loss will require a larger deficit because the BEE decreases (see
**calculate BEE**above) - Further calorie restriction or increased activity is required [5]
__LOW CALORIE DIET METHOD__- Low calorie diets will lead to weight loss in most overweight adults
- This method only requires that an individual count the number of calories they are consuming each day
__Low calorie diet__- A diet that consists of 800 - 1500 calories a day is considered a "low calorie diet" and will lead to weight loss in most overweight adults
__Very low calorie diet__- Diets that consist of < 800 calories a day are considered "very low calorie diets"
- These diets are not recommended because they are difficult to maintain and can lead to vitamin and mineral deficiencies [5]

**FINDING THE CALORIE CONTENT IN FOODS**

__FOOD LABELS__- For most store-bought foods, calorie content can be found on the label
__RESTAURANTS AND FAST FOOD__- Many restaurants and fast food establishments now have calorie contents posted on their websites
- Part of the new healthcare law requires restaurants to show calorie information for their foods
- On November 25, 2014 the FDA issued final rules requiring that calorie information be listed on menus and menu boards in chain restaurants, similar retail food establishments and vending machines with 20 or more locations to provide consumers with more nutritional information about the foods they eat outside of the home
- The FDA gave businesses one year to comply with the law [6]
__CALORIE DATABASES__- The American Diabetes Association has a helpful website that lists the nutritional information for hundreds of foods including many popular restaurant foods. It is available here -
**ADA website** - The USDA has a Nutrient Database which provides extensive information about numerous foods including restaurant foods. It is available here -
**USDA database**

**MACRONUTRIENTS AND ENERGY**

__There are 2 main nutritional categories:__**Macronutrients**- fats, protein, carbohydrates**Micronutrients**- vitamins and minerals__Macronutrients__- Only macronutrients provide calories
- Macronutrients consist of fats, protein and carbohydrates
- See the links below for an extensive review of each

**BIBLIOGRAPHY**

- What is PMID?
- PI = Manufacturer's Package Insert

__#____PMID__- 1 - PMID 16978504
- 2 - PMID 10993420
- 3 - PMID 15831804
- 4 - PMID 17558194
- 5 - PMID 9813653
- 6 - FDA website -
**CLICK HERE**