Runtastic

Running is one of the most popular forms of exercise on the planet for a few good reasons: it’s incredibly cheap (just buy some shoes and maybe a Spotify subscription for the Running Originals), it can be done anywhere (and anytime) and it’s effective.
There are tons of apps out there that can help you track your running stats. Map My Run, Nike+ Running, RunKeeper, Strava Running and Cycling and on and on. In truth, most of these apps are pretty good and have similar functionality. 
The history feature is awesome. It’s great to be able to compare past runs — including things like weather, running surfaces and even pictures.

MyFitnessPal

Despite a girly-looking logo, which perhaps adds to the stigma that only girls count calories, I’ve found MyFitnessPal to be an invaluable piece of my fitness and health app arsenal. It’s made me smarter about what I’m putting into my body and, as hinted at in the previous paragraph, it integrates with lots of other apps making it a health and fitness hub of sorts.
The easiest way to add a good item into the app is to scan it’s bar code. Simple. If you want to use this app just know that the first week or two will be the hardest and after that it’s relatively painless. That’s because recently entered items show up when you go to add a meal or a snack.

WaterMinder

WaterMinder is sort of like MyFitnessPal in that it helps you track what you’re putting into your body. But unlike the comprehensive MyFitnessPal, WaterMinder is laser-focused on one task alone: tracking water intake. And before you squawk too loudly that MyFitnessPal can track water too, I know, but…
WaterMinder has an awesome interface. It’s simple and fun: there’s a body that fills up with water as you add it. When you move your phone the water sloshes around. It’s a good visual indication of how close you are to your water goal.
The app itself gives some great reasons why you should care about drinking more water: it can help you lose weight, it can make your skin healthier, it can help prevent infections, it can help your brain work better and more.
Aside from seeing your daily fill and getting a percentage of what you’ve downed thus far (and how much further you have to go), you’ll also get a history which is a nice way to see how you’re doing over time.

Lark

Lark’s main feature is feedback: you enter in things like what you ate for the last meal and Lark tells you what’s up. Maybe it’s just me, but Lark is super positive too. It could find negative things to tell you (like you ate too much sugar today), but instead it seems to focus on positive reinforcement which is nice. It’s almost like talking to a friend.
And that’s exactly how it works. Lark simply has conversations with you (as if you’re texting a buddy).
The reason that it works is that it’s easy. You don’t have to remember to open the app to input stuff. If you turn on notifications (which I recommend and which aren’t at all too frequent or intrusive) Lark will strike up a conversation with you every now and then at times when it thinks you’re ready to talk.

Withings

The Withings app is one of the most important health and fitness apps on my iPhone. Not because of it ability to track steps or features similar to other health hub apps, but because it can accurately track weight by connecting with a Withings smart scale.
Whether you are in great shape or overweight, metrics like body fat percentage, heart rate and, of course, weight are important to track. The Withings smart scale — and accompanying app — are the perfect way to follow all three.
The Withings Healthmate app also integrates with Apple Health and other apps which means it doesn’t lock you into a separate tracking ecosystem.