There are a couple of reasons why you might be having issues with viewing your friend's meals correctly. The MyFitnessPal apps currently allow you to see other users' meals correctly only if all of the meal titles match exactly. On our site, we offer the option to add meals and customize meal names. Custom meal names can cause discrepancies when viewing the Diary via the app.
If this is the case, you will still be able to see a friend's full diary on the website. We hope to have a solution for the in-app diary viewing issue in a future update.
The other reason is that if your friend is experiencing sync issues with their app and our server, you will not be able to view their data. One way to check is to ask your friend to log in to their account online at www.myfitnesspal.com. If the data is not showing on the website, then there is no way you will be able to see it. We recommend having your friend reach out to our support at support@myfitnesspal.com so we can take a closer look at their account and hopefully resolve the issue!