Whether you’re trying to get ahead of a little holiday weight gain or just interested in keeping better track of what you’re eating, My Fitness Pal is an easy, yet robust app that should help you with your goals. It functions both as food diary and a source of advice — though, of course, you should speak with your physician before you embark on any major change to your diet and lifestyle. Its fairly complete database of food means you won’t have to spend a lot of time hunting around for nutritional information to input on your own. And its data not only show you how many calories you’ve consumed (and burned) throughout the day, but also give you information on how you’re doing on your intake of carbs, fat, protein and more. Users also can choose to share their progress with each other (because, sometimes, it’s not easy to go it alone). Finally, the app also works with several other popular fitness apps, including those for trackers such as Jawbone UP and Fitbit, to keep all your info in one easy-to-find place. Free, for iOS, Android, Windows Phone and BlackBerry devices.