Smartphone displaying new health app © Hadrian/Shutterstock.com

We may promise ourselves we’ll eat better or exercise more, but surveys show we rarely achieve our healthy-living goals.

A bit of motivation to stay on track may be what the wellness doctor ordered, and it’s right in your pocket.

Your smartphone can help set you straight and keep you moving, says Dr. Garth Graham, president of the Aetna Foundation, the philanthropic arm of the health insurance company. His research has focused on how mobile technology can change health outcomes.

Your phone “can empower you to make the right decisions around diet and exercise by providing you feedback” in real time, he says.

Here’s an example: Your smartphone can quickly tell you the calorie counts in two different foods you’re thinking of eating. The instant feedback means you can easily pick the healthier option.

Apps that encourage social media engagement can also spur you on. “It can inspire you to do more of an activity to meet a goal,” he says. It can also create an app-based buddy system “where you build accountability into what you’re doing.”

Free, but at a cost

What’s more, many of the top fitness apps are free. You can’t say that about the gym.

A word of warning, though: While you might not have to dig into your wallet to get these apps, you’re most likely giving something up in return for the free download, says Joe Schumacher, senior security consultant at Neohapsis, a mobile and cloud security services provider.

“You’re still paying a price for the information,” Schumacher says. He’s reviewed user agreements on a few health-related apps and says that they’re so vague that you can’t really tell what personal data the app developer is keeping — and selling. “You’re giving off a lot of sensitive data of yourself.”

Most users are fine with that; otherwise, these apps wouldn’t be so popular. But if you don’t want what you’re eating or where you’re running stored somewhere, you may want to skip free fitness apps altogether or look for a paid app that doesn’t sell your data.

Here are eight of the most well-known (or ubiquitous) health and fitness apps available today.

Apple Health

  • Price: Free
  • Available on: Comes preloaded on the iPhone 6 and iPhone 6 Plus. It’s part of the iOS 8 download, available on iPhone 4 and later, as well as the fifth-generation iPod Touch.

Apple Health tracks just about everything about you, including steps, flights climbed, workouts and sleep. It also links in with other apps and devices, like Jawbone’s UP, Garmin devices, fitness and calorie-counter apps to give a rounder picture of what’s going on in your body. You can also keep track of your body measurements and weight if you’re looking to drop some pounds. In its Medical ID section, the app stores medical information about you, like your blood type, allergies and whether you’re an organ donor.

Google Fit

  • Price: Free
  • Available on: Comes preloaded on all Android 5.0 Lollipop devices. It’s part of the Android 4.0 and later downloads.

Google Fit is more like a wearable tracker but in your phone. Unlike Apple Health, it doesn’t track health data. Google Fit automatically logs your movements and lets you set targets for each day. It can differentiate between walking, running and cycling, too, without you having to notify your phone as to what activity you’re about to do. You can manually input your workouts, too, if it’s not one of those three exercises, or have Google Fit draw in information from other fitness apps.

MyFitnessPal

  • Price: Free
  • Available on: Android, iOS

This free app includes a calorie counter (just put in what you’re eating, and that food’s information will be added to your food log) and exercise log with calculator to determine how many calories you burned in whatever activity you’re doing. MyFitnessPal does not track your exercise in real time (no GPS tracker here), but it does link up with a Fitbit or a Garmin if you use either of those devices, and inputs your exercise from there into the app, and vice versa.

Pedometer++

  • Price: Free
  • Available on: iOS

If you’re wary of wearables tracking your steps, this free app may be the answer. It tracks your movements and translates them into steps, miles and floors climbed. You can also set goals. It’s as simple as that.

RunKeeper

  • Price: Free
  • Available on: Android, iOS

This app turns your smartphone into a GPS tracking device. While walking or running, the app can give you updates through your earphones on things like time, distance and pace. (And if these updates annoy you, you can turn them off.) You can also take pictures to log along with your run and brag about your workout on Twitter and Facebook. If you’re bored with your regular routine or want to find a running route in a new-to-you city, you can search routes that other runners have uploaded in that area.

Tap & Track

  • Price: $3.99
  • Available on: iOS

This is a no-frills calorie counter that costs a few bucks. That’s because it has an offline database, meaning that your food searches and log stay within your account. It also allows you to input exercise if you want to see how that counteracts with what you’re eating that day.

Strava

  • Price: Free
  • Available on: Android, iOS

This free app is big in the cycling community, but it can be used for running, too. It captures information from your smartphone or one of more than 50 GPS-enabled devices, then data-tizes your activities so you can see how you’re doing and track your progress. It also allows you to compare your workouts with your friends and even professional athletes. You can also earn badges for meeting fitness challenges that are always changing (and often sponsored by fitness-related companies).

FitnessBuilder + FitnessBuilder Plus

  • Price: Varies
  • Available on: Android, iOS

The basic FitnessBuilder app, which is focused on weightlifting and strength training, is free. It includes pictures and videos of specific workout moves plus fitness plans, and stores your past workouts so you can keep a log. But if you’re looking to turn your smartphone into a personal trainer, upgrade to FitnessBuilder Plus, which costs $6.99 per month or $59.99 per year. To start, you’ll have access to more than 7,000 workout pictures and videos (versus 200 in the free edition) and more than 1,000 workouts (versus 400 in the free version), and you’ll also unlock the “Ask a Trainer” feature, which allows you to get one-on-one coaching. The upgraded edition also lets you create PDFs of workouts and customize your exercises.