Please try re-syncing your activities by completing the following steps:
1) In the Pact app, go into Start Activity > Select the Food pact icon (fork)
3) Tap "Sync Now" under the orange bar that indicates your successful connection to MyFitnessPal.
4) You will receive a confirmation if any new activities have synced
Here's a quick video on how to force sync your food logging activities: http://youtu.be/WBbGXfxsQss
If force syncing does not resolve the issue, can you send our CX team screenshot(s) from MyFitnessPal from the days of your missing food logs.