Why are there such a large difference on sardine packed in water between different brands? Some have more calories per 100g then others (by a lot)
I think it’s because sardines are a natural product. Because of that, the quality and nutritional value may fluctuate a bit. One fish might contain more fat than the other for example. Note that the nutritional value on any food is always just a snapshot
This is not or less the case with foods produced in factories.