Leftover potatoes, when not refrigerated quickly and properly, can develop Clostridium botulinum—the bacteria responsible for botulism. Reheating doesn’t always destroy this toxin, making reheated white potatoes a risky choice, especially for older adults.

Tip: If you must store potatoes, refrigerate them within two hours and heat them to a high internal temperature before consuming.

3. Mushrooms

Mushrooms contain proteins that are particularly sensitive to changes in temperature. When reheated, especially in a microwave, they can break down and produce digestive issues or even release toxins if not stored correctly.

Safer Choice: Only cook the amount you plan to eat, or enjoy leftover mushrooms cold in a salad or sandwich.

✅ 3 Foods You Should Reheat – Even Daily

1. Oatmeal

Reheated oatmeal is not only safe—it can be even healthier. Oats contain resistant starch, which supports gut health and can help control blood sugar. When oats are cooled and reheated, resistant starch levels increase, making them more beneficial for digestion and metabolism.

Pro Tip: Batch-cook steel-cut or rolled oats and reheat with a splash of milk or water for a quick, fiber-rich breakfast.

2. Brown Rice