Alexa Skills can give users access to accounts they've already set-up, such as the Alexa Skill for SiriusXM radio, ESPN, or even their car insurance if they have Alliance Insurance. With Alexa connected to these accounts, people can pull up details and content through their Alexa-enabled device. For example, the Alexa Skill for Major League Baseball lets Alexa users stay current with baseball stats and hear shows. Use the Alexa Skill for Fandango to not just find a movie but buy a ticket.
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."
If you want to do some casual research for a future trip, you can get fare estimates using the Kayak skill. You can say, "Alexa, ask Kayak where I can go for $400" or "Alexa, ask Kayak how much it costs to fly from Los Angeles to Dublin." The skill will ask for additional information and eventually provide you with a series of options and price ranges.