Whether you’re returning home late after a long day at the office or find yourself with precious little in the way of fresh ingredients in the fridge, grabbing a microwaveable meal often seems preferable to ordering another unhealthy—and expensive—takeout meal. However, while many microwave meals may bill themselves as healthy or diet-friendly, experts say they often do more harm than good. According to a 2015 study published in The British Journal of Nutrition, there were startlingly deleterious health effects recorded among adult study subjects who consumed prepared foods, including microwaved meals, on a daily basis.

You may be at greater risk forcancers

The ingredient list on the back of that microwave meal may not tell the whole story when it comes to what you’re actually consuming.

“Using electromagnetic radiation, the microwave causes food and the containers in which the foods are cooked to super-heat,” says Spencer Kroll, MD, PhD, an internal medicine specialist with Kroll Medical Group. “This super-heating can cause breakdown of the chemical components of the containers surrounding your food and these dangerous chemicals can potentially leach into your food.”

Your blood pressure may rise

Just because that microwave meal is low in calories doesn’t mean it’s good for you. In fact, the copious amounts of salt used to make many microwave dishes palatable could contribute to serious health problems down the line.

“Microwave ready meals are high in sodium and other preservatives,” says Kroll. “High sodium foods accelerate blood pressure problems and can lead to heart disease.”

You might retain water.

It’s not just your cardiovascular health that’s at risk when you consume sodium-laden microwave meals. As registered dietitian nutritionist Shena Jaramillo, MS, RD, explains, microwaved meals “are high in sodium which can lead to water retention.”

Over time, this may lead to other healthy habits, like drinking enough water, falling by the wayside.

You could put yourself at risk for food poisoning.

Though microwaving has been touted as a means of killing everything from viruses to bacteria, it may not actually mean you’re in the clear when it comes to food poisoning. In fact, it’s one of the microwaved meal side effects that could leave you sidelined in the short term.

You might see your waistline expand.

If you’re eating microwaved meals in an attempt to whittle your waistline, don’t hold your breath.

According to the British Journal of Nutrition study, greater consumption of prepared foods, including microwaved meals, “was found to be independently associated with abdominal obesity.”