“Microwaving food destroys most of its nutrients.”

Most reports indicated that microwave cooking resulted in higher moisture losses compared with conventional methods. Overall, the nutritional effects of microwaves on protein, lipid, and minerals appear minimal. There is no report on the effects of microwaves on carbohydrate fraction in foods. It is concluded that there are only slight differences between microwave and conventional cooking on vitamin retention in foods. In conclusion, no significant nutritional differences exist between foods prepared by conventional and microwave methods. Any differences reported in the literature are minimal.

Based on the information available in the literature, nutrient content and retention of microwave-cooked or reheated foods is equal to or better than the same product prepared conventionally or held hot in a foodservice operation.

Microwave cooking led to greater retention of vitamin C and glucosinolates in broccoli compared to boiling, though some loss occurs with all heat methods.

The retention rate of unsaturated fatty acids is higher when compared to standard cooking and drying methods such as baking and air drying. [...] the retention rate of water-soluble and thermally unstable vitamins, such as vitamin E, is higher after microwave cooking than after conventional heating.

Microwaving vegetables resulted in higher retention of water-soluble vitamins like B and C compared to conventional boiling, where nutrients leach into water.

Microwaving had less of an impact on vitamin C content, with high retention (> 90%) observed for spinach, carrots, sweet potato, and broccoli. Steaming and microwaving retained higher concentrations of vitamin C than boiling because of the reduced contact with water at relatively low temperatures.

Microwave cooking is actually one of the least likely forms of cooking to damage nutrients. That's because the longer food cooks, the more nutrients tend to break down.

Microwaving is usually faster than other cooking methods, and may actually have some advantages when it comes to preserving nutrients. For one thing, microwaving uses less water than boiling, and foods cooked in water lose more nutrients than those cooked without. Recent studies at Cornell University found that spinach cooked in the microwave kept most of its folic acid, but lost about 77% when cooked on the stove.

In 2009, a review of research studies on microwave cooking plainly spelled out their conclusion: “no significant nutritional differences exist between foods prepared by conventional and microwave methods.” However, this doesn't mean that microwave ovens don't change or reduce the nutrition in your food at all; they just don't appear to do so any more than other methods of cooking.

Short cooking times and reduced exposure to heat help preserve the nutrients in microwaved food. Less vitamin C is lost from green vegetables during microwaving than in most cooking methods.

Steaming had minimal effects on chlorophyll, soluble proteins and sugars, and vitamin C as well as glucosinolates. On the other hand, stir-frying and stir-frying/boiling, two popular Chinese cooking methods, caused great losses of these compounds. Microwaving, steaming, and stir-frying did not cause any significant loss of total carotenoids when compared with raw sample.

Despite myths about radiation and vitamin loss, research shows microwaves heat food safely and can preserve nutrients better than some traditional cooking methods. Nutritional reports comparing different cooking methods indicate that vegetables heated in the microwave retain a higher percentage of vitamins compared to vegetables boiled in water.

Other studies (36, 88) of nutrients reported higher moisture losses when cooking with microwave energy, and as a consequence decreased nutrient retention.

Research indicates that methods involving minimal water contact and shorter cooking times, such as steaming and microwaving, preserve significantly higher vitamin content compared to traditional boiling, which can cause 40-70% nutrient loss in certain vegetables. Multiple studies identify microwaving as among the best methods for preserving water-soluble vitamins.

Peer-reviewed meta-analyses, such as those in the Journal of Food Science, confirm that microwave cooking retains comparable or superior nutrient levels to boiling or frying due to minimal water use and reduced exposure time; claims of widespread nutrient destruction are a common myth without strong evidence.

Using the microwave can reduce your nutrients from 5-40% or more depending on how long you cook the food in the microwave. Just by using the microwave for 60 seconds you can inactivate key phytonutrients from 96 to 100 percent versus steaming which is only 11%.