Table for Two: Your App and You

You walk into a coffeehouse and look at the menu. Just as you are about to order a large coffee drink with whipped cream and caramel, your phone buzzes--it’s your nutrition app. The app reminds you that you are working on losing a few pounds and suggests that you get a latte with skim milk instead of the whipped-cream-caramel concoction you bought the last three times you were at the coffeehouse.

If this scenario sounds far-fetched, it shouldn’t. It describes what some app developers are already trying to do. For example, a pilot of Project Boundary the headquarters of the U.S. Department Health and Human Services includes several proximity sensors and transmitters around the building. The sensors detect the presence of a program participant. A transmitter then sends “nudges” to her cell phone with suggestions for health-related behaviors. If she is near an elevator, her phone might suggest taking the stairs. If she is near a vending machine, her phone might suggest drinking water instead of soda.

The vision of an app in your pocket that can help you live a healthier life is an attractive one. The iTunes store and Google Play have dozens of nutrition-related apps. These apps promise to help their users lose weight, make healthier choices at the market and at the table, and sometimes even make a little money. Unfortunately, the promotional materials don’t answer some important questions that would help users understand what they are really getting when they download the app.

How does the app get its data about the user’s health, location, food purchases and food consumption? Where else does this data go?

Apps seem to work “auto-magically.” Yet, even non-techies can understand how the “magic” happens if they think about how the app must work in order to do what it does. If the app knows you are in a coffee shop, it probably gets location information from your phone and compares that location with a database of business locations. If it knows what you bought in the past, it must have a database of past purchases. You might have entered those purchases yourself, or the app might receive data from a coffee shop, a supermarket, or some another participating business. If the app knows you want to lose weight, it has the health goals you entered. Or perhaps it decides on its own that you need to lose weight because it has data sent by your scale that morning. Thinking about the way an app must work will help you avoid unpleasant surprises, such as a sudden realization that the app (and the company that made the app) has a record of every food purchase you made.

Knowing where all your data goes is also important. After all, a combination of your location history, your health history and what food you’ve been buying and eating is attractive for many different businesses. Marketers want to use the data to serve you more personal ads. Merchants want it to sell you more of what they want you to buy. Your health plan wants to learn more about how your food history correlates with various health conditions. Learning where your data might go is not easy. One study found that most app privacy policies are long, difficult to understand, and sometimes don’t even address the app specifically. Nevertheless, it is important to try.

How accurate is the data on which the app’s recommendations are based? What level of accuracy is important?

Depending on what the app advises, accuracy of information may or may not matter. If the app advises you to buy a skim latte instead of a whipped-cream-caramel drink because you want to lose a few pounds, it may not matter how well it knows your health, the precise number of calories in the drinks, or whether it thinks that you drank the coffees you actually bought for your cube-mate. However, if you are a diabetic and the app advises you on what to order and how much to eat to balance your blood sugar level, the accuracy of its information is critical. As health-related apps proliferate and increasingly try to replace medical devices, the reliability of their sensors and backend databases is coming under increasing scrutiny.

How do the app creators decide what advice the apps should give? Is the app updated when new research comes out?

App developers decide what data bases to tap for nutritional information and what advice to offer their users. Unfortunately, users don’t usually know whether the advice has a sound scientific basis.

There is a lot of bad or incomplete nutritional information out there, and even some of the most trusted advice is not always based on sound research. For decades the U.S. dietary guidelines advised Americans to limit their intake of cholesterol and fat. When the US Federal Dietary Guidance Advisory Committee reviewed the science underpinning the guidelines in 2015, the Committee’s report received intense press coverage, at least in part because it overturned 40 years of nutritional advice. The Committee found no reason to recommend restrictions on foods rich in cholesterol, such as egg yolks, liver and lobster. It found no evidence that reasonable quantities of these foods harm most people. The Committee also backed off recommendations for limiting overall consumption of fat and salt. The report did advise people to reduce consumption of added sugar, which is found in most processed foods these days.

Research on food and nutrition does not always produce clear results, and the debates between researchers often play out in public. Is weight loss about balancing total calories consumed with total calories burned or does it matter whether the calories come from fat, carbohydrates or proteins? Are low-fat foods “healthy” if they contain added carbohydrates? Do organic foods provide better nutrition or just cost more? Nutrition apps offer advice without letting users know the uncertainties in the science behind it, or even what science they base the advice on, if any.

Before you download a nutrition app

Nutrition apps seem like a cheap and easy way to improve our lives. After all, even expensive apps probably cost less than a diet book, and they can do more. Apps can keep track of what we eat, allow us to see patterns in the data, and even “nudge” us to do better.

Nevertheless, it is important to understand what you get when you download and use a nutrition app. You need to ask questions about the way the app obtains, uses and discloses data, the quality of the data it uses for advice, and the scientific basis for recommended behaviors.

Some developers put in a general disclaimer that apps are provided for educational or entertainment purposes only. They even say that we should not rely on their apps as health and fitness tools. All the while, they build apps with attractive and authoritative-looking interfaces, advertise interesting functionality, and promote the apps as helpful. Downloading the app is cheap and easy, so we forget that apps collect real data about us, and that the science behind the apparently credible recommendations may be weak or non-existent. Before you spend money on an app, ask the developer why you should buy his product and rely on it. Then see whether you like the answers.