Adam Hoover, Eric MuthElectrical & Computer Engineering Dept

Psychology DeptClemson University

The Bite Counter

Outline

1. The obesity problem

2. Our concept

3. How it works (and how well)

4. Manufacturing

5. Pilot study

The Obesity Problem

More than 27% of U.S. adults, ages 20-74, are obese

U.S Department of Health and Human Services, 2007

Worldwide, over 1 billion adults (ages 15+) are overweight or obese

World Health Organization, 2009

Related health risks include cardiovascular disease, diabetes, cancer, and hypertension

$117 billion annualy to treat obesity-related issues in U.S.

Kelly, “Obesity: Health and Medical Issues Today”, 2000

New tools needed

04/21/23 4

• Joint NSF/NIH Workshop• (Ershow et al. 2007) “Engineering Approaches to Energy Balance and

Obesity: Opportunitites for Novel Collaborations and Research”

• Journal of the American Dietetic Association• (Thompson et al. 2010) “Need for Technological Innovation in Dietary

Assessment”• (McCabe-Sellers et al. 2010) “Advancing the Art and Science of Dietary

Assessment through Technology”

International Obesity Society: 10,000 researchersObesity Society (U.S.): 2,500 researchers

Balancing Energy Output and Intake

Tools can assist counting input and output

X Y+ = weight loss/gain

exercise diet healthy weight

Tools: Measuring Energy Output

Odometers measure time, distance, velocity

Provide rough estimate of calories burned

Commonly used in exercise

Tools: Pedometer

A pedometer is worn on the waist

Measures steps, e.g. during exercise

Can be worn all day, used anywhere

Tools: Measuring Energy Intake

Manually counting calories

Calorie or food diary

Pre-packaged foods and serving sizes

None of these are easy to use consistently over long periods of time

Our concept: Bite counter

Automatically tracks how many bites of food have been taken

Can vibrate to tell you when to stop eating

Worn like a watch

How do bites relate to calories?

Weight loss does not happen in a single meal (or bite); it takes weeks to months of consistently consuming less food

1 pound per week is a common guideline (American Heart Association)

People are bad at counting calories

Undercounting 200-500 calories per day (Champagne et. al. 2002)

Calories are not as accurate as we like to believe

Frozen dinners 8% under, fast food 18% under (Urban et. al. 2010)

People tend to eat the same foods week-to-week

Reduce the bites … reduce the calories

Does bite size matter?

At daily and weekly intervals, goals could be given to smooth out spikes in eating behavior

10-75, based upon our testing

Example: After a week of monitoring, we determine your average lunch bite count is 38; we recommend reducing that to 32

Example: Upon reaching dinner, the device indicates you have already consumed 183 bites today; a small dinner is recommended

How many bites do you eat in a meal?

Bite count goals will be customized to the individual, and will be based upon monitoring the individual for a week

Advantages of our device

Objective

No guessing, or thinking back over a day to total consumption

Automated

You can be doing other things (talking with friends, working, watching TV, etc.); the device does all the counting

Real-time feedback

The device can give you cues to stop eating BEFORE you have consumed more than you intended

How it works

The wrist undergoes a characteristic roll motion during the taking of a bite of food

Biologically, this can be related to the necessary orientations for (1) picking food up, and (2) placing food into the mouth

How it works

Tracking the wrist roll motion, we have identified a 3-event pattern that corresponds to the taking of a bite of food

Demo

How well does it work?

Experiment #1: Waffles

51 subjects, 139 meals, same food (waffles), same utensil

94% bites correctly detected

80% positive predictive value

Experiment #2: Any foods, in lab

47 subjects, 49 meals, any food (and drink), any utensil

88% bites correctly detected

76% positive predictive value

Talking, other actions during 67% of bites

Experiment #3: Two weeks

04/21/23 17

Test relationship between bites and calories• 83 subjects wore for 2 weeks• 3246 meals• 76% have correlation > 0.4• 69% between 0.4 and 0.7

Correlation: 0.4

Correlation: 0.7

Experiment #4: Cafeteria

04/21/23 18

Instrumented dining tableHarcombe Dining Hall; seats 800 people

How do we build it?

Embedded System Design

Lab model Watch model

Breadboarding and parts selection

gyroscope

LCD

processor

battery, holder

charger

I/O (buttons, speaker, vibratory motor, USB port)

Processor

development board dev board JTAG-USB

LCD

surfboard and custom breakout board

Gyroscope

typically follow “application circuit” from manual

Battery

How long will it run?

What can you wear?

Design stages

Breadboard Circuit diagrams

Design stages

Circuit diagrams Printed circuit board (PCB) & manufacturing

EEEA, Inc

Design stages

PCB Molding and case production

Center Line Technology

Design stages

PCB, case

Assembly

Bite counter PCB

gyroscope

processor

LCDbattery

USB port

USB-RS232 bridge

speaker

buttonsJTAG

charger