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."
Alexa Skills themselves are quite helpful. However, even with an updated Skills section in the Alexa app and the ability to add skills using only your voice, discovering new and useful skills is a less than desirable experience. So much so that Amazon actually created a skill called Skill Finder which, you guessed it, helps you discover new skills. Launch it by saying, "Alexa, open Skill Finder" or "Alexa, tell Skill Finder to give me the skill of the day."
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.