Adam Hoover, Eric Muth Electrical & Computer Engineering Dept Psychology Dept Clemson 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 5/11/20154 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 researchers Obesity Society (U.S.): 2,500 researchers

Balancing Energy Output and Intake Tools can assist counting input and output XY+= weight loss/gain exercisediet 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 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 5/11/ Test relationship between bites and calories 83 subjects wore for 2 weeks 3246 meals 76% have correlation > % between 0.4 and 0.7 Correlation: 0.4 Correlation: 0.7

Experiment #4: Cafeteria 5/11/ Instrumented dining table Harcombe Dining Hall; seats 800 people

How do we build it?

Embedded System Design Lab modelWatch 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 BreadboardCircuit diagrams

Design stages Circuit diagramsPrinted 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 LCD battery USB port USB-RS232 bridge speaker buttonsJTAG charger