Nestlé Hydration Calculator 01: Brief, Competitive Research and Data

A brief introduction: During my graduation internship at Poke I was asked to work on the Nestlé Pure Life website, specifically the hydration calculator and infographics. In this series of post, I’m writing about my design process and what I’ve been learning along the way.

Problem Analysis

The challenge

The health benefits of switching from carbonated sugary drinks to water are generally understood. However, there are many different opinions about how much water we should be drinking per day. As with most things, this depends on the individual and there are many associated factors, both internal and external. How can we help people find out their recommended water intake in a way that is tailored to their individual needs?

Additionally, organic search results for Nestlé hydration content are very weak. This needs to be changed.

Problem statement

How to make the hydration calculator as engaging, efficient and useful an experience as possible and how to leverage the calculator to achieve both business and user needs.

Business Needs:

  • Deliver an engaging experience by giving users information that helps them stay adequately hydrated.
  • Talk directly to engaged parents, promoting healthy hydration.
  • Offer a seamless e-commerce experience. According to Poke’s research, competitors do e-commerce badly. NPL has the opportunity to offer regular delivery service through the hydration calculator.

User Research

Since this is such a large-scale project, a lot of research had been conducted by the team at Poke before I started. The following personas that I received were part of the research outcomes.

4 personas that gave me a better understanding of whom I was designing for.

In addition to the personas, I also got the following list of 8 experience principles of the new Nestlé branding. I reviewed this list together with our Head of UX at Poke, Jen Williams. As Jen has been part of this project from the start, she advised me to focus on “caring, reassuring, and helpful” when it comes to the hydration calculator.

Experience principles

The understanding of the experience principles led me to question whether “fun” was still relevant to my criteria. This was included in my initial Implementation Plan.

Job Stories

Using the Jobs To Be Done framework, I explored different scenarios in which a user would want to find out their hydration needs. I created the following job stories based on my study of Sarah, Ricky, Jane, and Johan.

Competitor Review

I conducted a small competitor review on existing hydration calculators to see how others do it and also to set the bar for what we need to surpass.

What I looked at:

  • Purpose and the required data needed for the calculator.
  • Notable features and functionality.
  • Result for me: 50kg, 157cm, exercise daily, cloudy climate.

Who I looked at:


Non-competitor Review

I continued with a non-competitor review where I looked at various water tracker and fitness & health apps.

Some water tracker apps measure user’s recommended hydration needs before tracking their fluid intake. In other words, these apps tend to have a hydration calculator as part of their sign-up process.

On the other hand, fitness & health apps generally require similar inputs from users during the sign-up process. These include age, gender, weight, height, and activity level.

What I looked at:

  • For water tracker apps: I looked at how they calculate the recommended amount of daily water intake. Input types, the structure, and my result.
  • For fitness & health apps: I look at how they ask users for their sensitive information and form usability.

Who I looked at:


Summary of competitor & non-competitor review:

  • Input: Most calculators ask for user’s weight, activity level, and climate. Some ask for gender and height.
  • Results: Not very consistent across different calculators. My result fluctuates between 1.8 and 3.2 litres.
  • Usefulness: Most calculators give useful tips and facts. The IBWA Calculator even reminds users that food and other drinks also contribute to their total fluid intake.
  • Usability Observation: Use help text when asking for sensitive information. Related fields are grouped. Reduce the amount of thinking for your users (ie. pre-selected fields). Subtle movements and animations can add a lot to the total experience of users (examples from Lifesum). Error prevention using back buttons, sliders, radio buttons, drop-downs and checkboxes.


  • Be transparent about the methodology
  • Educate users as they go along by giving useful tips and facts
  • Only ask users for necessary information.
  • Result page: Make it useful and rewarding. Offer coupons, convert result into cups per day, show the best time to drink in a day…

Methodology Review

From the competitor review, I noticed that the results I received from different sources are quite inconsistent. They ranged between 1.8 litres and 3.2 litres. With an attempt to find out what the most realistic method to estimate your daily water intake is, I put together the following list of various methodologies that I collected from the internet.

  1. Myth: Drink at least eight glasses of water a day

Drink at least eight glasses of water a day (called “8 x 8” for short) has been a widely held belief. Is it really true? With an attempt to find a fair answer, I came across this research paper from Heinz Valtin of Dartmouth Medical School and several articles that back it up:

The brilliant research paper that I found online.

After an extensive research in 2002, Heinz concluded that it most likely came from the following passage. The passage is found in a book that Drs. Stare Fredrick co-authored with Dr. Margaret McWilliams in 1974. Here it is:

“How much water each day? This is usually well regulated by various physiological mechanisms, but for the average adult, somewhere around 6 to 8 glasses per 24 hours and this can be in the form of coffee, tea, milk, soft drinks, beer, etc. Fruits and vegetables are also good sources of water.”

Note two things: First, there is a huge difference between “…somewhere around 6 to 8 glasses” 7 and “at least eight glasses of water”. It was misinterpreted. Moreover, in “Drs. Stare and McWilliams’s passage, caffeinated and alcoholic drinks such as coffee, tea, soft drinks, and beer are allowed, whereas these categories are excluded by the proponents of 8 x 8”.

According to Heinz, there is no such thing as a universally true guideline governs ideal water consumption. “Water requirements depend so much on outside temperature, activity levels, and other factors that there isn’t one rule that fits everybody”.

2. Method suggested by Slender Kitchen

Formula: Your weight (pounds), multiply by 2/3. Then add 12 ounces of water to your daily total for every 30 minutes of work out (according to The American College of Sports Medicine recommends)

For example, I weigh 110 pounds and I exercise roughly 45 minutes daily so my water intake should be about 2.6 litres a day. Here is the math:
110 pounds s x 2/3 + 12 x 1,5 = 92 ounces = 2.614 litres

3. Method suggested by Katherine Isacks

Formula: Estimate the basic number based on body weight and age, using the chart below.

A simple method to estimate basic water requirement based on body weight, by Katherine Isacks.

Consideration: Ms. Mary Nadelen, a certified trainer, recommends that during exercise, 200 ml — 250ml of water should be consumed every 15 minutes.

For example, I am a 22-year-old adult who weighs 50 kg and exercise roughly 45 minutes a day, so my water intake from all sources should be about 2.35 litres — 2.75 litres. Here is the math:
35 ml /kg x 50 kg = 1.75 litres
40 ml / kg x 50 kg = 2 litres
200 ml /15' x 3= 0.6litres
250 ml / 15' x 3= 0.75 litres
Intake range = 2.35 litres — 2.75 litres

4. Method suggested by Jennifer Stone

Formula: Your weight (pounds), multiply by 1/2 = oz of water per day. Add 12 ounces of water to your daily intake for every 30 minutes that you work out

  • Special consideration: “If you are pregnant or breastfeeding, you need to increase your fluid intake by 24 to 32 ounces depending on how much you weigh, according to the American Pregnancy Association.”
For example, I weigh 110 pounds and I exercise roughly 45 minutes daily so my water intake should be about 2.07 litres a day. Here is the math:
110 pounds s x 1/2 = 100 oz = 1.56 litres
12 ounces x 1,5 = 18 ounces = 0.51 litres
Intake = 2.07 litres

5. Guidelines suggested by USDA

The US Department of Agriculture says people need from under one litre to nearly four litres a day depending on their age, sex and health status.

The guidelines below was taken from their Dietary Reference Intake report.

  • Newborns & Infants: 0.7 — 0.8 litres of water a day from breast milk or formula.
  • Toddlers: 1.3 litres
  • Young children up to eight: 1.7 litres.
  • Boys, ages nine to thirteen: 2.4 litres.
  • Teenage boys and adult men: 2.7 litres.
  • Girls, ages nine to thirteen: 2.1 litres
  • Teenage girls: 2.3 litres.
  • Adult women: 2.7 litres.
  • Women need at least 3 litres of water during pregnancy and 3.8 litres daily for lactation.

Other interesting findings:

  • Trust your thirst. It’s there for a reason. The thirst instinct is very reliable and has managed to keep us humans alive for a very long time (source).
  • People at the extremes of age, such as children and the elderly, are more at risk of becoming dehydrated (source).
  • Water need is also increased during pregnancy, breastfeeding, as well as several disease states like vomiting and diarrheas (source).
  • Older people are more at risk of becoming dehydrated because some studies show that the thirst mechanisms can start to malfunction in old age (source).
  • Rule of thumb: A light yellow urine colour is generally a good indicator that you’re well hydrated.

Methodology Summary

Putting my research findings together, it became clear that there is no universal method when it comes to water requirements. Thus, they only serve as a guideline. This was confirmed by the team on returning from a client workshop. It transpires that Nestlé’s approach is to advise and inform, never to prescribe.

I brought up this problem as soon as our UX team got back from the content workshop. I then got to know that the methodology will be handled by a team of researchers and scientists at Nestlé. They also told me that the methodology Nestle would be using was defined in the USDA’s Dietary Reference Intakes report, a guideline I had already found during my research. The team advised me to progress, using the questions already identified in my brief, knowing they would be commented on at a later date by the client.