When cooking, if you cook too much, it will become an overnight meal. Overnight meals will have a certain impact on your health. The most important impact is the production of carcinogenic nitrite. Especially some fresh green leafy vegetables often produce nitrite at this time, which will not only reduce the nutritional value of the vegetables, but also have adverse effects on health. Therefore, in daily life, you should try to eat as few overnight meals as possible. What are the dangers of eating overnight meals? 1. Overnight vegetables produce deadly nitrites. Some overnight vegetables, especially overnight green leafy vegetables, not only have low nutritional value, but also produce disease-causing nitrites. The amount of nitrite produced in stored vegetables increases as the storage time increases and the temperature increases. However, if the vegetables are refrigerated in the refrigerator (2-6 degrees Celsius), the increase in nitrite will be less. Some high-protein and high-fat leftovers are even more unacceptable. Harmful bacteria in the air will attach to leftovers and start to multiply within 2 hours. Everyone knows that under the action of bacteria, most proteins and fats will produce harmful substances, such as hydrogen sulfide, amines, phenols, etc., which are harmful to food. Harmful to human body. 2. Different types of vegetables with different parts have different hazards. Different types of vegetables produce inconsistent amounts of nitrite under the same storage conditions. Generally, stem and leaf vegetables are the highest, melons are slightly lower, and roots and cauliflowers are in the middle. Therefore, if you buy different types of vegetables at the same time, you should eat stems and leaves first, such as Chinese cabbage, spinach, etc. If you plan to cook more dishes to eat hot the next day, you should try to cook less stem and leaf vegetables and choose melon vegetables. Special reminder: Spinach, cauliflower, beans, cabbage, and green peppers will produce more nitrite on the second day after storage at room temperature. The nitrite in spinach far exceeds that of other vegetables. Those that produce less nitrite include tomatoes, lettuce, leeks, zucchini, eggplant, garlic sprouts, carrots, and celery. 3. The aquatic products that are most likely to cause gastrointestinal diseases. People usually think that vegetables that do not cause diseases will increase the nitrite content after being salted overnight, and the toxicity will increase after heating. Therefore, vegetables are the least suitable to be left overnight. In addition, starchy foods are best eaten at one time. Foods such as rice cakes can be stored for up to 4 hours. Eating them without changing their flavor may cause adverse reactions.