MyFitnessPal

As the name implies, this app turns your iPhone into your best friend for weight loss. It supports all your weight loss, weight gain and weight maintenance goals to help you stay in top shape.

Moreover, it offers personalized exercise plans and allows you to track your food, exercise, and health regimen. It also helps you change unhealthy habits, so it's like having a nutrition coach in your pocket or even on your wrist if you have an Apple Watch.

This is not only a regular fitness app with instructions on how to lose weight and stay healthy, but it is also a source of encouragement and motivation for you to be active. MyFitnessPal supports and guides users to follow a scientific exercise diet with a library of more than 350 different exercises and nutrition regimens. This software also helps you set goals and connect with friends who use MyFitnessPal to encourage and share experiences with each other.

Price: Free (MyFitnessPal Premium start from $9.99)