Point the camera at a product barcode (EAN/UPC) or a QR code. Barcodes are looked up in Open Food Facts. QR codes can hold a barcode, a GS1 link, or JSON like {"name":"Oat bar","calories":190}.
Recipes come from TheMealDB and don't include calories. Enter kcal per serving the first time you log a recipe, and BiteLog remembers it for next time.