The Short Version
This claim is not supported by scientific evidence. Over a dozen peer-reviewed studies consistently show that microwaving retains nutrients at levels comparable to — or better than — conventional cooking methods like boiling or frying. Key vitamins such as vitamin C show retention rates above 90% when microwaved. All cooking causes some nutrient loss, but microwaving is actually among the least damaging methods due to shorter cooking times and less water contact. The word "most" dramatically overstates the reality.