The leftover spaghetti in the fridge would certainly be easier to warm up rather than cooking a new meal, however it might not be the healthiest decision.
Yes, it is really convenient to warm up leftovers from the past two nights, but it can also cause some health issues. However, not all leftover food is spoiled, some of it is. It sucks to throw out expensive food that was fresh a day ago, but it is necessary to remain healthy. These are the foods that you never want to reheat!
Vegetables
You never want to reheat vegetables after about a day. Celery, lettuce, beets, and spinach all have stored accumulated nitrates that can be detrimental to your health. It can cause a rare blood disorder in children called methemoglobinemia. If you are trying to save vegetables for longer than a day, they need to be frozen. Otherwise, throw them out!
Vegetable oil
of course, you aren’t going to heat up vegetable oil and dig in, however, you might reheat meats and other foods that were cooked in it. In fact, reheating vegetable oil has been linked to heart disease, stroke, and an increased risk of cancer!
Chicken
Chicken is known to be the perfect living environment for many different bacteria. It also contains lots of proteins that can take a violent turn when reheated. If you are reheating chicken make sure that it is hot all the way to the core.
Rice
This is one of the biggies. You never need to reheat rice. Uncooked rice has spores of harmful bacteria that can survive the first cooking process. If it is then stored at room temperature, the spores can double and even multiply. They can also cause a world of digestive issues! If you have to reheat rice, add some water and cook it on the stove again. Make sure it is thoroughly hot all the way through.
Food is expensive these days, no doubt. It seems like it is harmless and cost efficient to be reheating your leftovers. While it is, you have to be careful what you’re reheating. To avoid the risks, cook as much fresh food as you can!