A calorie counting app can be helpful if you are trying to lose weight and being mindful of what calories are in what foods, and how many you will burn with exercise.
I'd recommend checking out the following apps if you're interested in keeping track of your calorie intake:
Losing weight is a fairly straightforward equation: You need to burn more calories than you consume, so in this respect, an app will no doubt be really helpful.
Calorie counting isn't everythingCalorie counting is only one part of weight loss and a healthy lifestyle, and in my opinion, is something that people can become unnecessarily fixated upon. Whilst it's good to be aware of the nutritional value of food, I believe you can do this without becoming obsessed with kilojoules.
Realistically, you can divide food up into three groups- foods you should eat regularly, foods you should eat occasionally, and foods you should eat rarely. If you follow these guidelines and add exercise into the equation, you will reach your goals without having to worry about counting calories.
But in saying that, weight loss is a personal thing, and what works for some people will not work for others, so if you need more structure, then a calorie counting app might be great.