The brain is the most complex organ in the body. It regulates everything from body temperature to memories to breathing and generates thousands of thoughts every day.

So, how do we keep our gray-and-white matter in top form?

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That’s what we — Raj Punjabi and Noah Michelson, the co-hosts of HuffPost’s “Am I Doing It Wrong?” podcast — asked Dr. Madhureeta Achari, a neurologist in independent practice for 30 years, when she recently dropped by our studio.

Listen to the full episode by pressing play:

Achari said the “No. 1 reason” for many of the problems she sees in patients is that they are “nutritionally deficient.”

The United States is suffering from “high-calorie malnutrition,” she noted, which means individuals are eating a lot of food but aren’t getting the vitamins and minerals they require from it.

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“The brain has to have a balanced diet,” she said. “In terms of vitamins ... each of them does something. It’s like a finely tuned machine. So you can’t just fix one part, right? It’s like a car. If everything’s great, but one tire is flat, the car is still not going to go.”

Achari advised that if trying to get everything we need to keep our brains in superb shape feels “overwhelming,” we should concentrate on “eating the rainbow.” 

“[We should be eating] lots of fresh fruit and vegetables, whole grains — I think 90% of us, or something, consume most of our grains in an ultra-refined form. We need to go back to whole grains, whole foods, meats, fish, poultry that is whole ... and you want some dairy, and you want some nuts and seeds ... and you want to try to, throughout your day, get all of those things.”

Achari tells her patients to avoid supplements that claim to enhance brain function and instead focus on nutrition. 

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“They don’t help you,” she said, noting that the “wellness industrial complex” has promoted the “weird idea that somehow we are smarter than our bodies.”

So, if you want to keep your brain as healthy as possible, “feed your cells” a wide variety of foods full of micronutrients daily, Achari said, and chew your food well.