There is a growing tendency on social media to share recipes for the preservation and consuming of food leftovers, especially after holidays and parties. This particular food fad bothers me as a holistic physician.

One of the tenets of living healthy is to turn to nature for nourishment and to eat without reprocessing food. Procure your fresh ingredients and decide just how much you are going to cook so that you will not be wasting natural resources and at the same time, will not be putting your body in jeopardy by reprocessing a partially decomposed food product.

I have a lot of friends and colleagues who cook up copious amounts of food and just keep reheating it whenever they need it throughout the week. However, there are some foods that should never be reheated. Not only does the nutritional value of these foods wane with repeated heating, but with these particular foods, the molecular structure of the substance changes to carcinogenic or otherwise harmful, so it is best to avoid reheating these five foods:

  1. Beets
  2. Potatoes
  3. Eggs
  4. Mushrooms
  5. Rice

Reheating of these foods produces altered protein structures in eggs and mushrooms and nitrites in beets and potatoes, both of which are potentially carcinogenic for humans. This was evidenced by several randomized studies published in the last 10 years. In addition, reheating rice and potatoes can cause botulism and other bacterial diseases. In fact, reheating fried rice accounts for an estimated 63,000 cases of bacillus cereus food poisoning each year within the United States. Some people with low immunity can have critical complications due to this infection.

In general, to avoid decomposition of food, try to eat what you have cooked right away or at least within 24 hours, so that the leftovers will not become a breeding ground for bacteria and fungi. Many people continue to reheat opened soups and sauces and that is just a disaster waiting to happen. The majority of people with food poisoning would develop diarrhea or vomiting as symptoms, but many others may just walk around with other subtle signs of spoiled food toxicity, such as burping, heartburn, headache or itchy rash.

I encourage you to cook every day if at all possible. It’s not easy, but at the same time it can be a very therapeutic de-stressor and a chance to be mindful about what you are going to eat in terms of nutritional value and portions. If it is absolutely impossible for you to cook every day, at least tightly seal and refrigerate or freeze the leftovers in glass or ceramic containers.