Vittles: accomplishing a healthier lifestyle
Master Computer Science, Human-Computer Interaction
Department of Computer Science, KULeuven, Belgium
Abstract—The abstract goes here.
Upon looking at the important risk factors that are related
to illness and death in most countries, one can uncover
that they arist from non-transitional diseases such as high
blood pressure, high cholesterol, low consumption of fruit
and vegetables, overweight and obesity, sedentary lifestyle
and smoking. Except for smoking, these risks are related to
nutrition and physical activities. Overconsumption of proteins,
fats, carbohydrates and alcohol can cause an excess of energy
that gets stacked in the body. Consequentially, a combination
of lowering the energy intake (what is eaten) and raising the
energy consumption (physical activities) are needed in order
to obtain a healthy energy balance. 
A. Dietary intake
An important aspect of monitoring the dietary intake is
the registration of what is actually eaten by the user. This
registration can be done manually a user can enter what he/she
ate or automatically. Here, it is important that it is easy for the
user to register the dietary intake and that it does not consume
too much time. 
Self-monitoring is proven to be a critical skill for successful
weight management.  In entering what a user eats, an
important concept is that of the kCal. It is an amount that
is used frequently in the context of eating and participating in
B. Energy consumption
In addition to the dietary intake, the activities of a person
also relate to the amount of calories that can be consumed or
that are burned. However, even while sitting idle (or sleeping)
a user consumes energy. This energy consumption can be
calculated according to the Harris-Benedict equation, which
considers the basal metabolic rate (BMR). For men this can
be calculated as:
88.362 + 13.397w + 4.799h − 5.677a (1)
with w the weight in kg, h the hight in cm and a the age in
A whole range of activities exist. And each activity burns
a certain amount of energy. This amount is, for example,
proportional to the level of intensity (e.g. by running you burn
more calories than by walking) or the duration. 
The importance of sports in relation to personal health and/or
weight management is stressed by multiple studies , ,
, . Regular exercise has been shown to help people
maintain their healthy lifestyle and weight loss more easily.
C. Setting goals
Goal setting has been shown to be important to ones ability
to control ones behaviour.  Setting small, reachable, but
challenging goals is an important step in keeping a person mo-
tivated to keep going. , , ,  The road of loosing
weight and maintaining a healthy lifestyle can be challenging.
And some days will be easier than others. Therefore, a positive
stimulant is important.
Working with goals has some important issues to keep in mind
however. Firstly, goals direct the attention, efforts and actions
of the user towards goal-relevant actions. This can be at the
expense of non-relevant (but important) actions.  Second,
making the goals too difﬁcult to reach, can have a negative
effect on the user. In addition, feedback is important : people
need to be able to track their progress. 
People like to reﬂect on their daily activities, much as they
do with a diary, and they can become quite attached to it as
it provides them with a better understanding of what happens
and why.  The goal setting theory here we have to goal of
managing ones weight or obtaining a healthy lifestyle states
the importance of feedback. If people do not know how they
are doing, it is difﬁcult or impossible for them to adjust the
level or direction of their efforts or to adjust their performance
strategies to match what the goal requires. 
Quantiﬁed Self  is a technology movement that tries
to accomplish selfknowledge through visualizing big data
elements, including gamiﬁcation elements and using sensory
equipment in a mobile environment. By employing this in the
project, the user can be triggered to discover ﬂaws in his/her
dietary habits or activity schedule. By gaining this insight, it is
desirable that the user can draw enough conclusions and will
get motivated or stimulated to turn bad habbits into good ones.
This way the user can obtain a healthier lifestyle and, as a side
effect, weight loss.
III. RELATED WORK
Currently there already exist many applications that try and
accomplish similar effects. These applications are mostly based
on the input of a user and this of both dietary consumption
and activity logging. By comparing the existing applications,
some strengths or weaknesses could be discovered. This can
than be included in the design of Vittles. The following ap-
plications were compared i.a.: Calorie Counter by FatSecret1
, Weight Watcher Mobile3
Upon comparing these applications, some important criteria
were chosen. These criteria simplify the comparison and help
with the creation of a benchmark where the important aspects
are indicated. These criteria include the options of entering
food elements as well as activities, setting (user deﬁned)
goals, inclusion of gamiﬁcations and/or a rewarding system,
retrieving reports about the users progress or status and the
social character (integration with social media or an ’in game’
friend list) of the application.
As a conclusion of this study, it was found that currently only
little automation is employed. In addition, most application
do not point out weaknesses in the users lifestyle or caloric
consumption. However, connections with friends, setting goals,
facing challenges and getting visual feedback appear stimulat-
For the design of Vittles it is important to consider the way
we expect users to provide input to the application. As seen
in literature , this can be automated. This automation can
be accomplished by letting the user take a picture of the meal
he/she is consuming. This will mostly lower the amount of
time that is requested from the user. However, the accuracy is
often much lower than with manual input. Nonetheless, input
of data should be fast and easy. 
Next to chosing the way users will enter data, it is also
important to select a device that will be employed by the
application. Herein it is important to note that mobile appli-
cations are widely used and can provide a unique mechanism
for collecting dietary information that reduces the burden on
record keepers. Also, the always-on and always-carried nature
means that users can self-monitor anytime and anywhere. 
This leaves the door open for either smartphones or tablets.
Previously the importance of reports and feedback was already
stressed. With this in mind, the application will mainly be
developped for tablets, since these have bigger screens and
users can browse through their reports more efﬁciently.
Also, a thing to consider is when it is expected that the user
enters information. For example this could be done at the
beginning of the day. When working in a prospective manner,
we could focus on advising the user to eat something healthy.
Hereby the role of the application would be to point out better
or healthier alternatives. On the other hand, the application
could work in a retrospective way. Hereby, the user would enter
what was eaten. Consequentially an advisatory approach would
be less effective. In this approach it will be better to point out
weaknesses and to prevent them from happening again. For the
design of this application a retrospective approach was chosen.
Finally, some design criteria were determined before starting
with the actual design of the application. These criteria are
important elements for reaching the goal of this research. The
design criteria include:
• Consistency: An important aspect of any good ap-
plication, is consistency. For this study, this means
that adding a food item should by similar to adding
3http://www.weightwatchers.be/templates/marketing/marketing utool 1col.
an activity. Also, the transitions between screens, the
coloring etc. should be similar.
• Creating entries in the caloric diary: As with many
of the reviewed applications, an important element of
the application will be a diary. In this diary both food
items and activities will be logged. However, adding
something to the diary should be fast and easy. The
user should be able to do it without having to doubt
their actions and without losing too much valuable
• Simplicity: For the application I do not expect the
users to be experts in nutritional values of food items
nor activities. Hence, the application should be easy
to understand. Throwing around nutritional numbers
might be handy to some, but it can also scare off
others. Mainly in elements like own recipes, it seems
unpractical to make the user work with nutritional
values. The system should calculate the values auto-
• Social character: The application will work with an
internal user base, where friends can be made. This
will not be coupled to a proﬁle on other social
networks. Every user will get their own proﬁle-page,
where his/her badges and completed challenges can
be consulted by their friends. In addition there will
be a timeline-page, where a stream of updates from
the users friends will appear. This social aspect could
then be exploited so that users could stimulate each
other to work towards a more healthy lifestyle.
• Setting goals: The user should be able to set some
goals for himself/herself. Upon creating an account
the application will make a suggestion. However, at
all times the user should be able to adapt the goal. In
addition, the progress should be visualized in an way
that is quick and easy to understand. Goals should
not only be based on a weight loss/gain target and
the user should be able to set more than one goal.
When reaching a goal, the user should receive some
reward. Next to actual goals, the system can register
bad habits. When discovering such a bad habit, the
user will receive an update containing a suggestion to
change it. This could make it easier for the user to ﬁnd
the cause(s) of their unhealthy lifestyle and to change
for the better.
• Gamiﬁcation: Badges, Challenges and Goals. They are
important gamiﬁcation aspects that will be included
in the application. They should make the application
more compelling, so that the user would remain stim-
ulated to keep going and to work towards a more
V. METHODOLOGY: RAPID PROTOTYPING
For the design of the application, an iterative method was
chosen. Hereby, an initial prototype is constructed and then
iteratively tested and adapted, so that a ﬁnal (digital) design can
be accomplished. The ﬁrst two prototypes that were designed,
were designed on paper. By designing on paper, it is easy to
give the user an overview of the look and feel of the application
Fig. 1: SUS scale  with the score for the second paper
without having to spend too much time on the creation of the
prototype. In case problems arise, the design can also be easily
adapted, without having to concider the technical or monetary
complications that could acompany an adaptation.
For the evaluation of the paper prototypes a combination of
widely used techniques were used. Firstly a think aloud user
test  was conducted. With this test, the test person has
to perform some predeﬁned steps and in that way navigate
through the application. This to discover if the test person
had any difﬁculties with speciﬁc aspects of the prototype and
whether or not some functionalities are highlighted appropri-
ately. Secondly, the user was asked to ﬁll in a questionnaire
(after the think aloud test). This questionnaire contained three
• Personal questions: to get an idea about the back-
ground of the user. In this section questions about their
weight (problems) were asked.
• SUS-questionnaire: to (simply and easily) get
an idea of the the usability and simplicity of the
application. The SUS questionnaire can be translated
to a score that represents the quality of the interface.
An overview of meaning of the scores can be found
in ﬁgure 1.
• Detailled questions about the application: to get a
better idea of (un)needed functionalities or other issues
with the application.
After the paper prototype was sufﬁciently evaluated, the
transition to a digital version could be made. The digital
version should resemble the paper version as much as possible.
Again, this prototype is evaluated in a similar manner. TODO:
something about the evaluation of the digital prototype.
VI. OVERVIEW OF PROTOTYPES
In this section the different prototypes that were developed
are discussed together with their evaluation and the results.
There were two paper prototypes developed, followed by one
A. First paper prototype
The ﬁrst paper prototype was designed mainly in a digital
environment. This was initially chosen to, on the one hand,
easily get the look and feel of a digital application, and, on the
other hand, since good tools exist for creating such prototypes.
This prototype is shown in ﬁgure 2.
This prototype was evaluated by only a little number of
(a) The main screen (b) Food diary
(c) Activity logbook (d) Report view
Fig. 2: First paper prototype
test users (four). This since the design was not immediately
percieved as innovative. In addition, a lot of issues arised from
this evaluation. Therefore, I decided to stop the development of
this prototype and focused on changing the design. Important
lessons learned from this evaluation was that at that point, the
application appeared very click based and included a whole
range of functionalities. Consequentially, the next iteration
would have to focus more on creating a smooth ﬂow of
all operations and in addition, focus more on what the core
B. Second paper prototype
The second prototype (ﬁgure 3) introduced a different look
and feel. Mainly the stream of adding items to the food and
activity diary were completely adapted. This prototype was
developed solely on paper. This made it faster and easier
to develop, mainly because the tool that was used in the
previous iteration was quite limited when considering non-
The evaluation of this prototype was done as described in
section V. There were seven test persons involved in the test
phase with ages between 21 and 25 years old. Four of the test
persons had overweight and thus matched the target audience.
The ﬁrst issue that arised from the evaluation was that adding
an item was mostly hard to ﬁnd. However, there exists large
consistency between the food diary and the activity logbook,
since once the users knew how to use the food diary, they
could easily work with the activity logbook as well. Another
thing that came up during the think aloud tests, was that it
is counterintuitive to enter data (like your weight) in a report
view. Challenges and having a friend network are positively
received by most test users. The SUS score of this evaluation
was 81, which corresponds to the ’excellent’ label as shown
in ﬁgure 1.
(a) The main screen (b) Food diary
(c) Adding to the food diary (d) Report view
Fig. 3: Second paper prototype
C. First digital prototype
Since the second paper prototype did not introduce any
major issues with the design or the usability, we transfered to a
digital version (ﬁgure 4). This is mainly a digitalized version of
the paper prototype from the previous iteration. Minor changes
are made, so that they ﬁt current ﬂat design standards.
TODO: write about the evaluation of this prototype.
VII. SOFTWARE DESIGN
(a) The main screen (b) Food diary
(c) Adding to the food diary
Fig. 4: First digital prototype
TODO: ﬁgures of the software design with explanation of
TODO: the application will be used by multiple users for a
longer period. The results from this will be mentionned here.
In this paper a design is introduced that tries to stimulate
users of all age categories who suffer from overweight or
obesity to reach a healthier lifestyle and as a consequence
lose weight. This is accomplished by a system of feedback
through report views and goal setting, gamiﬁcation aspects
such as collecting badges and facing challenges and a social
character that can be exploited to the beneﬁt of the user. This
design resulted in an mobile application, called Vitles, via rapid
prototyping. This consists of different iterations, each having
their own design, development and evaluation phase.
TODO: formulate results at the end.
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