Food for Thought: Can the Paleo Diet Heal Mental Disorders?

The Paleo Diet is one of the latest trends in eating plans, promising to deliver leaner bodies and heightened energy. But David Perlmutter, author of "Grain Brain: The Surprising Truth About Wheat, Carbs, and Sugar," supports the diet primarily because of the benefits he says it can have on your brain.

In his book, Perlmutter, a neurologist and fellow of the American College of Nutrition, writes that grains cause degenerative brain disorders, including dementia and Alzheimer's disease, and play a role in attention-deficit hyperactivity disorder, epilepsy, anxiety, migraines and depression. Gluten, which is a "glue" that holds flour together, is the main culprit of obesity and why people suffer from brain diseases, Perlmutter says. Most people have gluten sensitivity, he writes, because humans were never wired to eat foods such as cookies, pizza and bread. The bread products of our ancestors also had lower levels of gluten than today's processed foods. When your body encounters gluten your blood sugar spikes, causing inflammation and severe harm to your brain, he says.

As a result, Perlmutter preaches: Ditch the carbs, take up aerobic exercise and you can control your genetic destiny. He also devised his own diet plan, which he lays out in "Grain Brain." The diet is similar to the Paleo Diet, though it allows for small amounts of dairy, legumes and gluten-free grains such as rice and quinoa, a few times each week.

In an interview with U.S. News, Perlmutter addressed critics' concerns about Paleo and shared lifestyle tips he says will optimize brain health.

[Search: U.S. News Top-Ranked Hospitals for Neurology & Neurosurgery.]

What You'll Eat on Grain Brain

Grain Brain closely resembles the Paleo Diet, also known as the Stone Age or Caveman Diet, which mimics our ancestors' eating habits and is comprised of foods people have eaten for 2 million years -- mainly plants, fruits and meat.

In Best Diets Overall. The warned that a lack of dairy and grains in their diet could lead to nutrient deficiencies. They also noted that Paleo followers need to be careful about making lean meat choices; otherwise, they may increase their risk for heart problems.

Yet Perlmutter disagrees. "The idea that people are nutritionally deprived because they don't eat grain has no scientific basis," he says, adding that the nutritional value of grain products is nothing more than a marketing ploy.

Though the staunchest Paleo followers rid dairy products from their diets, Grain Brain allows them in moderation. Cottage cheese, yogurt and kefir, for example, can be used sparingly in recipes or as toppings. The Grain Brain diet is essentially a vegetarian diet with animal products as a side dish, or "a vegetarian diet with qualifiers," Perlmutter says. You can ditch the meat entirely, or have meat portions no larger than the size of a deck of cards.

When it comes to red meat, Perlmutter says, people need to be selective and eat only the meat of animals that have been grass fed. Most cattle are fed genetically modified grain, not their natural diet of grass, which he says is high in fatty acid and provides what the brain needs for optimum health. The brain contains 60 to 70 percent fat, Perlmutter says. Therefore, the more fat and cholesterol you eat, he explains, the healthier your brain will be.

The typical American diet is high in sugar and carbs, which are harmful for the brain, he says. Many people begin their day with orange juice, which he says is pure sugar, followed by whole-grain cereal. "By 10 a.m. you're breaking open the vending machine at work because your blood sugar has plummeted," he says. You will not feel this fluctuation on a fat-based diet, he says.

Instead, consider this example of a day on the Grain Brain diet: For breakfast, have half an avocado drizzled with olive oil and two poached eggs topped with salsa. For lunch, eat lemon chicken with herb garden salad and balsamic vinaigrette. At dinner, enjoy salmon with mushrooms and unlimited roasted vegetables. For dessert: Two chocolate truffles.

While some people on the Paleo Diet customize it to what they think is reasonable, the Grain Brain is less flexible. For example, Paleo followers may allow themselves to eat gluten once a week, or an occasional slice of birthday cake. But Pelmutter does not encourage even occasional "cheating," since he argues one slice of cake still affects the brain. "Halfway measures work halfway," he says. "Even small amounts of cheating can have large inflammation results."

Fitness

Our ancestors moved a lot, and so should we, according to the Paleo exercise plan. The Paleo Diet suggests 2.5 hours of moderate to intense activity a week, while the Grain Brain exercise regimen focuses on getting your heart rate up through aerobic exercise, Perlmutter says. Spend 20 minutes a day walking, jogging, using the elliptical or biking.

Exercise stimulates the growth of new brain cells, Perlmutter says. "There's no prescription that can do this," he says. "All you have to do is exercise."

Certain exercises that involve stretching, like yoga, are good for mobility, flexibility and balance, he says, but tend to be less optimal for reaching memory goals. Continue yoga classes, he says, but couple them with aerobic exercise like Pilates or take your program to the next level by doing hot yoga.

[Read: Don't Just Diet -- Exercise to Lose Weight, Too.]

Supplements and Sleep

Perlmutter lists seven "Super Supplements" he says nourish the brain. They include: DHA, an omega-3 fatty acid; resveratrol, a supplement that slows aging; turmeric, a supplement that improves glucose metabolism; probiotics, which fight bacteria; alpha-lipoic acid, an antioxidant; and coconut oil and vitamin D. People who decide to follow the Grain Brain regimen can expect to pay about $50 a month for supplements.

And don't forget to sleep, which allows the brain to heal itself on a daily basis, Perlmutter says. People should try to maintain a regular sleep schedule by waking up and going to bed at the same time each day. He adds that you should sleep at least seven hours a night and allow at least three hours between mealtime and bedtime.

It's never too late to change your diet, fitness and eating habits, he says, because you have the ability to grow new brain cells your entire life.

[Read: How to Fall Asleep When It's 4 a.m. and You're Wide Awake.]