The 37-year-old mom of three, known for her super strict diet, sticks to all organic, gluten-free and dairy-free foods in her home, while staying clear of sugar and soda. Another thing she avoids? Microwaves.
“One kitchen appliance I never use is a microwave,” she writes on her app and website. “If anything needs to be heated up, I prefer to use the oven, stovetop or toaster oven instead.”
The health fanatic explains that she first enforced the rule after she had her first baby. “When I had Mason, I did a lot of health-related research and decided to get rid of my microwave when I read that toxins from plastic containers can be transferred to food when reheated (this applies to BPA-free plastic containers too),” she says.
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Even swapping out plastic containers for glass and stainless steel didn’t do it for her. “I didn’t want to risk having something reheated in plastic when I wasn’t around,” she adds.
People love microwaves because they’re quick and efficient—but the eldest Kardashian sister disagrees, praising her toaster oven instead.
“It only takes a few more minutes and the toaster oven heats food evenly (whereas microwaves can sometimes heat food unevenly, so some parts are scorching hot and others are cold, which is obviously a concern for babies and children),” she says.
“Also, I’ve heard that microwaves can leach nutrients from food and use radiation to heat food,” she continued. “I’m not sure how accurate this is, but when it comes to my family I play it safe.”
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This article originally appeared on PEOPLE