Scientific Basis of eaTracker

This background document provides users and health professionals with details about eaTracker, the food and activity databases, the source of nutrition and activity recommendations, and their interpretation.

Purpose of eaTracker

The purpose of eaTracker is to help consumers better understand their eating and activity choices.  This interactive web tool lets consumers track their eating and activity choices, analyze their recipes, plan meals and set goals for healthy eating and physical activity.  Users can post pictures or quotes to keep them motivated and determined to succeed.  Users can also sign up to have a Registered Dietitian be their “Coach” to help them achieve their healthy eating and weight goals.  The eaTracker web tool also lets users track their progress over time.  Users will get a summary of their feedback based on the food and activity choices they made over their last seven visits.  Whenever they visit eaTracker, users will see the goals they have achieved.  The eaTracker web tool provides recipes as well as fitness and nutrition tips to help consumer learn how to eat well and keep active. 

Personalized feedback is provided based on the user’s age, gender, weight, height, whether they are pregnant or breastfeeding, and the activity level they selected in their profile.  The feedback includes:

          Body Mass Index (BMI)

Canada’s Food Guide Servings

Nutrients listed on the Nutrition Facts table, with an option to expand the reported list to potassium, the B-Vitamins and Vitamins D and E

Calories consumed from food and beverages and burned in physical activities

Time spent in physical activities 

The results are based on the food and activity choices the user made on one specific day.   To get a better picture of usual eating and activity habits, it is recommended to repeat eaTracker on several different days. 

Target - eaTracker is appropriate for individuals 14 years and older, males and females, pregnant and breastfeeding women.

Food Database & Food Search

The food included in the food search and the nutrient data is from the Canadian Nutrient File, Health Canada, 2010.

The serving size for each food is based on the Food Guide Servings used in Eating Well with Canada's Food Guide, Health Canada, 2007

Food Selection

Food items are searchable by the full or partial name of the food e.g. milk, chicken, cream cheese, bread stick. The search results provide a scrollable list of foods containing that food name.

When entering the quantity of a food or beverage consumed, the user can enter partial portion sizes. For example, if you eat a half of a muffin, enter 0.5 for the quantity consumed. Users are reminded to add beverages, snacks, oils and fats, and vitamin supplements. Search tips and advice for what to do if user can't provide a food are provided.

Try simplifying your search by searching for one word (e.g flax). Also, check the spelling (e.g. broccoli not brocolli). If a food cannot be found it may not be in the database. You may need to choose an alternative food item that is similar to the item you are searching. You may make a suggestion using the feedback button to suggest a food be added to the database. Please be advised that we cannot guarantee that all suggestions will result in a food being added to our database.

Recommended number of Food Guide Servings

Eating Well with Canada's Food Guide, Health Canada, 2007 recommends a certain number of "Food Guide Servings" depending on age and gender (see Daily Food Intake Pattern). The user's intake of foods is compared to the age specific recommended number of Food Guide Servings.

Daily Food Intake Pattern as outlined by Canada's Food Guide

Males

14-18y

19-30y

31-50y

51-70

71+y

Vegetables and Fruit

8

10

8

7

7

Grain Products

7

8

8

7

7

Milk and Alternatives

3-4

2

2

3

3

Meat and Alternatives

3

3

3

3

3

 

Females

14-18y

19-30y

31-50y

51-70

71+y

Pregnant

Breastfeeding

Vegetables and Fruit

7

8

7

7

7

7-8

7-8

Grain Products

6

7

6

6

6

6-7

6-7

Milk and Alternatives

3-4

2

2

3

3

2-4

2-4

Meat and Alternatives

2

2

2

2

2

2

2

The food database calculates the number of Food Guide Servings for each food that is in a Food Group. The total number of Food Guide Servings are tallied and rounded to half servings.

Energy & Nutrient Recommendations

eaTracker is appropriate for individuals 14 years and older and thus nutrient data feedback is provided for male and female teens and adults, as well as pregnant and breastfeeding women.

Energy

Energy (kcal) is reported as actual intake (based on total calories consumed) and is compared to Estimated Energy Requirements (EER) based on age, weight, height, and activity level and whether the user is pregnant or breastfeeding. National Academy of Sciences. Institute of Medicine. Food and Nutrition Board.

The Estimated Energy Requirement (EER) is defined as the dietary energy intake that is predicted to maintain energy balance in a healthy adult of a defined age, gender, weight, height, and level of physical activity consistent with good health.

The Estimated Energy Requirements (EERs) equations are from the Institute of Medicine (IOM) Dietary Reference Intakes macronutrients report (2002). These equations provide an estimate of energy requirement. Relative body weight (i.e. loss, stable, gain) is the preferred indicator of energy adequacy.

Equations to estimate energy requirement

Boys 14 -18 years

88.5 - (61.9 x age [yr]) + PA x (26.7 x weight [kg] +903 x height [m]) + 25

Males 19 years and older

662 - (9.53 x age [y]) + PA x (15.91 x weight [kg] + 539.6 x height [m])

Girls 14 – 18 years

135.3 - (30.8 x age [yr]) + PA x (10 x weight [kg] +934 x height [m]) +25

Women 19 years and older

354 - (6.91 x age [y]) + PA x (9.36 x weight [kg] + 726 x height [m])

Pregnancy & Breastfeeding: girls 14 to 18 years

First trimester - same as teen female EER
2nd trimester - teen female EER + 340 calories*
3rd trimester - teen female EER + 452 calories
Breastfeeding - teen female EER + 330 calories

Pregnancy & Breastfeeding: women 19 years and older

First trimester - same as adult female EER
2nd trimester - adult female EER + 340 calories*
3rd trimester - adult female EER + 452 calories
Breastfeeding - adult female EER + 330 calories

* The 2nd trimester EER was used in eaTracker for pregnant and breastfeeding women.

Physical Activity Coefficients (PA values) for use in EER equations

 

Sedentary
(PAL 1.0-1.39)

Low Active
(PAL 1.4-1.59)

Active
(PAL 1.6-1.89)

Very Active
(PAL 1.9-2.5)

 

Typical daily living activities (e.g., household tasks, walking to the bus)

Typical daily living activities PLUS 30 - 60 minutes of daily moderate activity (ex. walking at 5-7 km/h)

Typical daily living activities PLUS At least 60 minutes of daily moderate activity

Typical daily living activities PLUS At least 60 minutes of daily moderate activity PLUS An additional 60 minutes of vigorous activity or 120 minutes of moderate activity

Boys
3 - 18 y

1.00

1.13

1.26

1.42

Girls
3 - 18 y

1.00

1.16

1.31

1.56

Men
18 y +

1.00

1.11

1.25

1.48

Women
18 y +

1.00

1.12

1.27

1.45

Source: Dietary Reference Intakes Tables
ISBN: 0-662-41134-X
Cat. No.: H44-87/2005E-HTML
www.hc-sc.gc.ca/fn-an/nutrition/reference/table/index_e.html

Protein, Fat and Carbohydrate

Protein, fat and carbohydrate are reported as total intake (grams), as a percentage of total calories, and then are compared to the recommended range defined in Dietary Reference Intakes for Energy, Carbohydrates, Fiber, Fat, Protein and Amino Acids (Macronutrients), National Academy of Sciences, 2002.

Protein: Recommended range 10 - 35% of total calories

Fat: Recommended Range 20 - 35% of total calories for adults and 25-35% of total calories for 14 to 18 year olds.

Carbohydrate: Recommended range 45-65% of total calories.

Percentage of total energy (calories) coming from protein, fat, carbohydrates and alcohol are calculated as follows:

% of calories from protein = (grams of protein x 4 kcal/g) divided by total calories x 100

% of calories from fat =
(total fat in grams x 9 kcal/g) divided by total calories x 100

% of calories from carbohydrate =


(grams of carbohydrate – fibre/2) x 4 kcal/g, divided by total energy (kcal) x 100

 

% of calories from alcohol =
(grams of alcohol x 7 kcal/g) divided by total calories x 100

Example calculations:

User ate 1800 calories, 100 grams of protein, 60 grams of fat, and 225 grams of carbohydrate, including 15 g of fibre)

(100 g protein x 4 kcal/g) divided by 1800 kcal x 100 = 22 % of calories from protein

(60 g fat x 9 kcal/g) divided by 1800 kcal x 100 = 30 % of calories from fat.

(225 g carbohydrate15 g fibre/2) = 217.5 x 4 kcal divided by 1800 kcal x 100 = 48% of calories from carbohydrate.*

*Quick estimations of percentages of calories from protein, fat, carbohydrate and alcohol are typically based on factors of 4, 9, 4 and 7 calories per gram respectively. Because many carbohydrates in fact yield less than 4 calories per gram, the total of percentages calculated by this method usually is greater than 100%. To produce a total to 100% one can prorate each individual percentage. This adjustment will, however, overstate the percentage of calories from carbohydrate and understate that from fat. To provide a closer estimate of the actual percentages eatracker compensates by deducting half of the fibre from the carbohydrate before multiplying by 4 calories per gram.  The American Diabetes Association recommends this deduction to patients who are counting carbohydrate grams.

Nutrient Recommendations and Feedback

Results are reported for Calories and 13 core nutrients found on the Nutrition Facts table, with an option to expand the reported list to potassium, the B-Vitamins and Vitamins D and E.  Nutrients are expressed as total intake and as percent of Daily Recommended Intake.

 

Nutrition Facts Label

 Nutrient

 Units

Recommended

Daily Intake1 2

 

Y

Calories

kcal 

EER

Y

Fat

g

 

AMDR expressed in grams

Y

Saturated

g

*

Y

Trans

g

*

Y

Cholesterol

mg

 *

Y

Sodium

mg

AI

E

Potassium

mg

AI

Y

Carbohydrate

g

AMDR expressed in grams

Y

Fibre

g

RDA

Y

Sugars

G

**

Y

Protein

g

AMDR expressed in grams

Y

Vitamin A

RAE

RDA

Y

Vitamin C

mg

RDA

Y

Calcium

mg

RDA

Y

Iron

mg

RDA

E

Vitamin D

mcg

AI

E

Vitamin E

mg

RDA

E

Thiamin

mg

RDA

E

Riboflavin

mg

RDA

E

Niacin

NE

RDA

E

Folate

DFE

RDA

E

Vitamin B6

mg

RDA

E

Vitamin B12

mcg

RDA

 

* Saturated fat, trans fat, cholesterol - should be as low as possible while consuming a nutritionally adequate diet.

** Sugars – no recommendation for daily intake

 

1, Recommended Daily Intakes are based on Dietary Reference Intakes (DRIs) published from 1997 to 2005 for all nutrients except calcium and vitamin D which were updated in 2010. National Academy of Sciences. Institute of Medicine. Food and Nutrition Board. See Health Canada for Dietary Reference Intake Tables.

 

2. Estimated Energy Requirements (EER) are based on your age, weight, height, and activity level and whether pregnant or breastfeeding. National Academy of Sciences. Institute of Medicine. Food and Nutrition Board.

 

Percentage of Recommended Daily Intake for vitamins, minerals and fibre were calculated as follows:

The total intake of particular nutrient was divided by the Recommended Daily Intake and multiplied by 100 to get percentage of Recommended Daily Intake.

For example, if a 29 year old female consumed a total of 300 mg of calcium and the Recommended Daily Intake is 1000 mg/day: 300 divided by 1000 mg x 100 = 30 % of the Recommended Daily Intake.

Vitamin and mineral supplement data were selected from Canadian vitamin manufacturer websites accessed in June, 2011.

Activity Database & Activity Search

Physical activities are searchable by name. The list of activities is based on research that identified common activities that 90% of Americans do daily (Dong L, Block G, Mandel S. Activities Contributing to Total Energy Expenditure in the United States: Results from the NHAPS Study. Int J Behav Nutr Phys Act. 2004 Feb 12;1(1):4). This list has been adapted to apply to the Canadian population and includes activities recommended by the Canadian Physical Activity Guidelines developed by the Canadian Society for Exercise Physiology.

If an activity cannot be found, try simplifying your search by searching for one word or browse by category (e.g. if you can't find "Nordic skiing" try "skiing"). You should also check the spelling of the activity. If an activity cannot be found it may not be in the database. You may need to choose an activity that is the most similar to the activity that you are looking for (e.g. if you are looking for "carpentry" choose "housework - home repair" instead). You may make a suggestion using the feedback button to suggest an activity be added to the database. Please be advised that we cannot guarantee that all suggestions will result in an activity being added to our database.

Activity categories for time spent in activities of different intensities

The activities were categorized into 3 different activity levels based on the number of metabolic equivalents (MET) or the rate of energy expenditure each activity provides.  One MET is considered a resting metabolic rate obtained during quiet sitting. Activities are listed according to METS ranging from 2 METs for walking at a slow pace to sleeping to 16 METs for running at 16 km (10 miles) per hour. The METs were derived from the "Compendium of physical activities: an update of activity codes and MET intensities" by Ainsworth BE, Haskell WL, Whitt MC, Irwin ML, Swartz AM, Strath SJ, O'Brien WL, Bassett DR Jr, Schmitz KH, Emplaincourt PO, Jacobs DR Jr, Leon AS. Med Sci Sports Exerc. 2000 Sep;32(9 Suppl):s498-504.

  • Low Effort Activities (2.0 - 3.0 METS OR less than 3.5 kcal/min)
  • Moderate Effort Activities (3.0 to 6.0 METS OR 3.5 - 7 kcal/min)
  • High Effort Activities (Greater than 6.0 METS OR more than 7 kcal/min)

Activity Recommendations and Feedback 

Results are based on the total time spent in moderate to high intensity activities as recommended by the Canadian Physical Activity Guidelines developed by the Canadian Society for Exercise Physiology.  

Activity Time:

For youth aged 12-17 years, at least 60 minutes of moderate- to vigorous-intensity physical activity daily is recommended. Youth should include vigorous-intensity activities at least 3 days per week. 

150 minutes of moderate- to vigorous-intensity aerobic physical activity per week, in bouts of 10 minutes or more.

Muscle and Bone Strengthening Activity:

For youth aged 12-17 years, activities that strengthen muscle and bone should be done at least 3 days per week.

For adults aged 18 and over, the recommendation is muscle and bone strengthening activities using major muscle groups at least 2 days per week.

The Canadian Physical Activity Guidelines do not indicate the amount of time required in bone strengthening activities.  For the purposes of eaTracker we chose a minimum of 15 minutes in any muscle or bone strengthening activity to count.  This was done under advisement from CSEP Certified Exercise Physiologists.

Calories Burned in Physical Activities

The activities included in the activity database were used to calculate the calories burned in activity.  The database does not include sedentary activities such as sleeping, sitting, driving a car, etc.

The METS were used to calculate the calories burned or used in physical activities.

Data used for calculations

o    Body mass in kg

o    Minutes spent in activity

o    MET of activity

Calculation:  Kcals = body weight (kg) x time in activity (min) x MET (kcal/kg/hr) ¤60 min

-          based on the fact that 1 MET = 1kcal burned/kg/hr (i.e. 5MET = 5kcal/kg/hr)

-          Example: A 60 kg woman walks at a speed equivalent to 5 METS for 30 mins

o    Calories burned = 60 kg x 30min x 5MET / 60 min/hr

o                          = 150

 

Calories burned or used in activity feedback

 

This was calculated using the equations to estimate energy requirement and the physical activity coefficients (PA values) based on the physical activity level chosen by the user on their “My Details” page (i.e. sedentary, low active, active, very active).

 

The feedback includes:

 

o    the calories needed for basic body functions such as breathing, digesting, etc. and your activities of daily living (e.g. moving around the house, office, etc.)

o    the calories for the activity level indicated on the “My Details” page

o    the calories burned in physical activity from the activities the user selected on the activity search

 

The Feedback compared the calories burned in activities to the calories needed for their selected physical activity level.

 

If the calories burned are within 50 calories needed for their selected PA level - the calories you burned in activity are close to the calories you need for your stated activity level. 

 

If calories burned are greater than 50 calories needed for their selected PA level - the calories you burned in activity are greater than the calories you need to use based on your stated activity level.  If you keep this up you should start to lose weight.  You may need to have more calories if your goal is to maintain your weight.   If the increased activity level from today becomes normal, you may want to increase your activity level category on your “My Details” page.

 

If calories burned are at least 50 calories less than needed for their selected PA level – the calories you burned in activity are less than the calories you need to use based on your stated activity level.  This may result in weight gain over time. If this was an unusual day you are probably fine, but if not and you are hoping to maintain your weight, you may want to consider adding more activity in your day to use more calories. 

 

Sample calculations

 

User:  29 yr old female, 55 kg. 1.62 m, not pregnant or breastfeeding

-          example #1 – sedentary

-          example #2 - low active

 

Formula to use:  (Woman 19 yrs +)

354 - (6.91 x age [y]) + PA x (9.36 x weight [kg] + 726 x height [m])

 

Example #1

If self-selected PA level = Sedentary (PA coefficient = 1)

(i.e. accounts for BMR (basic body functions & processes) plus typical daily living activities (e.g., household tasks, walking to the bus))

 

354 – (6.91 x 29) + 1 x (9.36 x 54 + 726 x 1.62)

354 – (200.4) + 1 x (1681.56)

= 1835 calories

 

Interpretation:

A 29 yr old female weighing 55kg and 1.62 m should consume approximately 1835 calories/day to remain in energy balance, when she is not participating in any activity above and beyond activities of daily living (i.e. typical household tasks, walking to the bus etc.).

 

If this woman then decides to participate in extra activity in addition to daily living, 2 situations could arise.

1)    She could expect to see weight loss if she does not increase her calories consumed.

2)    She could increase her calories consumed to match the extra energy burned during exercise to remain in weight balance.

 

Example #2

If self-selected PA level = Low active (PA coefficient = 1.12)

(i.e. accounts for BMR, plus typical daily living activities PLUS 30 - 60 minutes of daily moderate activity (ex. walking at 5-7 km/h))

 

354 – (6.91 x 29) + 1.12 x (9.36 x 54 + 726 x 1.62)

354 – (200.4) + 1.12 x (1681.56)

354 – 200.4 + 1883.35

= 2037 calories

 

***Difference between EER for low active female vs sedentary female

= 2037-1852

= 202 calories

 

Interpretation:

To account for the 30 – 60 min of daily moderate activity that this woman does, she should consume 2037 calories / day (i.e. 202 calories more than would be predicted if she was sedentary.)  If she maintains both this activity level and this energy intake, she should remain in energy balance.

 

However, if this woman decreases her activity level, she must also decrease her calorie intake, or weight gain may occur.  In a similar sense, if she increases her activity level, without increasing her calorie consumption, weight loss may occur.