In the frozen aisle. In reality, however, the opposite is often true: frozen and canned produce can have many more nutrients than its fresh counterparts. That's because the moment produce is picked, its nutrients start to degrade. Plucking a fruit or vegetable from the tree, bush, or vine takes it away from its food source, so it starts using up its own nutrients to stay alive. The produce you find in the grocery store may have taken days or weeks to get there and experienced significant nutrient changes as a result. In order to keep it from spoiling before reaching its destination, fresh produce is also usually picked before it's ripe, so it doesn't even contain all the nutrients it could. Canned and frozen produce, on the other hand, is processed right when it's ripe, so its nutrients are locked in and aren't given much of a chance to degrade over time.
Then why do people say the opposite? It's true that canning and even freezing can expose fruits and vegetables to some amount of heat, which can destroy nutrients. But compared to the natural degradation that fresh produce experiences, that nutrient loss is often pretty minimal. The biggest losses are in water-soluble vitamins like vitamin B and C; according to a systematic review in the Journal of the Science of Food and Agriculture, broccoli loses 13% of its vitamin C when refrigerated for 21 days but a whopping 50% when frozen. But it found that other nutrients, in particular antioxidants like polyphenols, hardly degrade at all in freezing and canning processes. Of course, processing always leaves room for unhealthy additives like sodium, and produce picked and eaten that day is healthier than any alternative. But in general, there's no need to avoid canned or frozen produce. When it comes to fruits and vegetables, the amount you eat is more important than the form they take. Learn more about the science of food storage with the videos below.