I use mysugr, which lets you input your blood sugar, carbohydrate intake, insulin doses, details of your meal (I think that's it). I don't know if it does for Dexcom, but you can automatically import your libre data by linking your scanning app on your phone to it, and I also have mine linked to Google Fit to track activity. Not an iphone user, so don't know if you can do that with myfitnesspal, which I'm not familiar with. But I like mysugr, much better than carrying around three or four different notebooks!