Your doctor called. She wants you to switch things up.

Father Son Eating Cereal
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Having a meal routine is one thing. Eating the same foods day after day is another entirely, and it's one that can wreak havoc on your health.

"Humans were designed to graze and hunt, and therefore our diets became naturally varied," nutritionist Monica Auslander Moreno, MS, RD, LD/N recently explained to Reader's Digest. "This is likely an evolutionary design so that we attain and access a wide variety of nutrients throughout the day, week, month, and over long-term periods of time to optimize our body's functions."

It turns out that ingesting the same foods every day can damage a number of your body's most important systems. Not to mention taking all the fun out of eating, which can lead to dieting slumps.

"Our bodies need a wide range of macro- and micronutrients, and eating a wide variety of foods, especially fruits and vegetables, can help us meet our body's needs," Wesley Delbridge, RDN, spokesperson for the Academy of Nutrition and Dietetics, explained to Reader's Digest.

Take your gut, for example. According to Delbridge, eating a wide variety of foods is essential to promoting the healthy bacteria your body needs to drive digestion. "Fermented foods, such as yogurt and kefir, provide the probiotics (healthy bacteria)," he noted. "Eating fruits and vegetables provides fiber and prebiotics (food for the probiotics) to create a healthy gut environment."

It's also possible to "overdose" on certain ingredients. "Too much turmeric, for example, can interfere with blood clotting and liver function," Auslander Moreno said. And eating fish every day (particularly predatory fish like tuna) might mean you're ingesting a whole heap of harmful toxins like mercury. Instead, she recommends wild low-mercury fish like salmon, mackerel, herring, and anchovies.

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To make sure you get enough of what you need and avoid loading up on potentially toxic foods, Delbridge suggests "eating the rainbow."

"Eat the colors of the rainbow when it comes to fruit and vegetables, and don't forget that frozen vegetables are just as healthy as fresh, and they don't spoil as quickly."

And don't forget: eating should be fun.