Because Amazon opened up the development of Alexa Skills to anyone with the free Alexa Skills Kit (ASK) in 2015, anyone can create an Alexa Skill. As Alexa uses Natural Language Programing (NLP), those looking to build a skill don't need to worry about complex speech recognition. The ASK tools also makes it easier for novices to work with sophisticated NLP ideas.
For tracking your food, you can use the Track by Nutritionix skill, which lets you record your food intake using your voice, or ask for caloric values of foods. (Alexa does the latter by default.) Say things like, "Alexa, tell Food Tracker to log a cup of almond milk" or "Alexa, ask Food Tracker how many calories are in two eggs and three slices of bacon."
In the Alexa app, this is achieved by selecting the main menu button (found in the upper left-hand corner of the screen) and choosing the Skills option. From here you can browse Alexa skills by category or other criteria such as those favored the most by its large user base. You can also search for skills by keyword or name through this same interface.
Note: Your Flash Briefing settings apply to all Alexa devices registered to your Amazon account, and all users in your home get access to the same Flash Briefing content. However, if you or anyone in your home has a voice profile, Flash Briefing automatically skips stories and news items you've already heard. To learn more, go to About Alexa Voice Profiles.