5 Simple Steps to Nourishing Your Brain

B-list foods to include

• Beans and other legumes​
• Whole fruits (in addition to berries)​
• Low-sugar, low-fat dairy (e.g., plain yogurt, cottage cheese)
• ​Poultry​
• Whole grains

C-list foods to limit

• Fried food​
• Pastries, sugary foods​
• Processed foods
• ​Red meat (e.g., beef, lamb, pork, buffalo)​
• Red meat products (e.g., bacon)​
• Whole-fat dairy high in saturated fat, such as cheese and butter ​Salt

SLAY PUBLIC ENEMY #1

Sugar is public enemy #1 to a healthy brain. How much sugar you consume relates directly to metabolic health, which then plays directly into brain health. Nearly 35 percent of all U.S. adults and 50 percent of those sixty years of age or older are estimated to have what’s called metabolic syndrome, a combination of health conditions you don’t want to have, such as obesity, high blood pressure, insulin resistance, type 2 diabetes, or a poor lipid profile (too much bad cholesterol, not enough good cholesterol).

Since 2005, researchers have found correlations between diabetes and Alzheimer’s disease, especially when the diabetes is not controlled and a person suffers from chronic high blood sugar. Some scientists have gone so far as to refer to Alzheimer’s disease as “type 3 diabetes,” because the disease often involves a disrupted relationship with insulin, the body’s chief metabolic hormone. At the root of type 3 diabetes is the phenomenon that neurons in the brain become unable to respond to insulin, which means they can no longer absorb glucose, leading to cell starvation and death. Some researchers believe insulin deficiency or resistance is central to the cognitive decline of Alzheimer’s disease and could be implicated in the formation of those infamous plaques that bungle up the brain’s systems.

People with type 2 diabetes—a disease characterized by the inability to manage healthy blood sugar levels—may be at least twice as likely to develop Alzheimer’s disease, and those with prediabetes or metabolic syndrome may have an increased risk for having predementia or mild cognitive impairment (MCI), which often precedes dementia. But you don’t need to have been diagnosed with type 2 diabetes to be on the path to Alzheimer’s. In other words, studies are now showing that people with high blood sugar, regardless of a formal diagnosis of diabetes, have a higher rate of cognitive decline than those with normal blood sugar. The studies are clear: Get your blood sugar under control and avoid metabolic dysfunction—your brain (and your waistline) will thank you. And the first thing you can do to support healthy metabolic function is to slash that sugar. In doing so, you’ll likely slash a lot of salt as well.

2. H: Hydrate smartly

One of my mantras is “drink instead of eat.” We often mistake hunger for thirst. Even moderate amounts of dehydration can sap your energy and disrupt your brain rhythm. Because our brains are not really that good at distinguishing thirst from hunger, if there is food around, we generally tend to eat. As a result, we walk around overstuffed and chronically dehydrated. Or we quench our thirst with the wrong drinks. Beverages are the leading category source of added sugars (47 percent of all added sugars). Let’s see if we can avoid the brain-sapping beverages and drink brain-friendly ones this week.

Here’s your cheat sheet:

• Drinks to ditch or severely limit (this should sound familiar): diet sodas, sweetened teas, energy drinks, blended coffees, milk shakes, smoothies, and juices (including pulverized vegetable drinks or pressed juices)
• Drinks to enjoy in moderation: coffee and tea, but cut yourself off from caffeinated beverages by 2:00 p.m. so as not to interrupt sleep
• Unlimited drinks: filtered fresh water—aim to drink half of your body weight in ounces daily (so if you weigh 150 pounds, that means drinking around 75 ounces)
• If you don’t drink alcohol, don’t start now. Recent studies have shown that alcohol reduces overall brain volume even at light-to-moderate consumption. If you drink alcohol, drink in moderation. For men, doctors recommend they drink only up to two drinks a day (a drink is 12 ounces of beer, 5 ounces of wine, or 1.5 ounces—one shot glass—of liquor); for women it’s one drink.

3. A: Add more omega-3s from dietary sources

The impact on the brain of omega-3 fatty acids from foods has been extensively studied, and a wealth of information links omega-3 fatty acids and a healthy brain. The best way to consume more natural omega-3s is to incorporate more of the following into your diet from food (the evidence is not established that supplements work the same!). Check some of these off your grocery store list this week:

• Raw, unsalted nuts: almonds, hazelnuts, walnuts, cashews
• Seeds: sesame, flax, hemp, pumpkin, chia, sunflower
• Whole olives​
• Avocados
• ​Extra virgin olive oil. Canola, peanut, and avocado oils are high in omega-3s, but I prefer extra virgin olive oil in cooking and dressing dishes because it is rich in antioxidants, healthy monounsaturated fats, and compounds like polyphenols that are extra good for the brain. Many brands of extra virgin olive oil will make a “reserve” variety that’s richer and has more robust, complex flavors from a more selective process of choosing which olives to use. ​
• Fatty fish: salmon, trout, herring, sardines, anchovies, albacore tuna, mackerel, oysters, Arctic char, black cod

When buying fish, know where it’s coming from. Avoid fish from polluted waters or places where the mercury content in the fish can be too high. Mercury is a heavy metal that can harm the brain and is not easily eliminated from the body. The Monterey Bay Aquarium’s Seafood Watch website can help you choose the cleanest fish (wild or farmed) that are harvested with the least impact on the environment.

4. R: Reduce portions

You can automatically rein in your portions by preparing meals yourself at home, using smaller plates, and avoiding second and third helpings. You know what you’re putting into the meals you cook and have better control over ingredients and portion sizes. When possible, avoid frying and turn to boiling, poaching, steaming, or baking. This is yet another reason to cook more at home: You get to decide which method to use and control for those mystery oils, sauces, and added ingredients that come with food from restaurants. If you’re at a restaurant, ask for a to-go container when you order. When your meal arrives, eyeball an adequate portion and put the rest in your box.

In Keep Sharp, I didn’t thoroughly address fasting, but I want to share some new research that has emerged since its publication. It appears that the very act of restricting your calories, and I will define that in a moment, induces an altered metabolic state that, according to a 2019 review paper, “optimizes neuron bioenergetics, plasticity and resilience in a way that may counteract a broad array of neurological disorders.” The authors even boldly state: “Fasting improves cognition, stalls age-related cognitive decline, usually slows neurodegeneration, reduces brain damage and enhances functional recovery after stroke.” The benefit may be coming entirely from just eating fewer calories, though another paper suggests limiting your calories creates surges of beneficial stem cells to replenish the cells unable to survive the fast. I don’t think the data is strong enough to recommend one type of fasting over another, but there are generally four types of fasting (“intermittent fasting”) to consider.

• Time-restricted eating (the 16/8 or 14/10 split). In this option, you have set fasting and eating windows. For example, under the 16/8 protocol, you eat only within an eight-hour window and fast the remaining sixteen hours.
• The twice-a-week method (the 5:2 method). Following this formula, you eat normally for five days per week, then on the other two days you reduce your calorie intake to a quarter of your daily needs. For most women, this means reducing your caloric load to about 500 calories per day; for men, it’s about 600 calories. Do not fast on back-to-back days. Have regular eating days in between the fasting days. For example, Mondays and Thursdays can be the days you fast.
• Alternate-day fasting. Using this method entails limiting calories every other day (again, restrict to 500 calories for women and 600 for men), and eating normally on the other days.
• The twenty-four-hour fast (or eat: stop: eat method). Before trying a full twenty-four-hour fast, however, it’s ideal to experiment with the previous options first and be sure to take into consideration any metabolic conditions you have. If you’re diabetic, for example, you will want guidance on any kind of fasting regimen.

You should check with your doctor before trying any intermittent fasting protocol. Do not fast if you have a history of blood sugar problems, heart conditions, or eating disorders. There remains plenty of debate on intermittent fasting, with conflicting data and different outcomes in different people. Intermittent fasting can affect you in ways you may not expect so if you want to try it, ease into it and journal the experience in detail to document how you feel, how your hunger cues change, and whether or not you’re getting what you want out of it (e.g., weight loss). It’s not for everyone. Again, check with your doctor first.

Here’s how to take the beginner’s route: Simply start by cutting yourself off from food and caloric beverages by 7:00 p.m. (drinking water is okay) and skipping an early breakfast, delaying the morning meal to 11:00 a.m. By taking advantage of your natural overnight abstinence, it’s practically effortless to reach a fasted state. Every hour after the twelve-hour fasting mark moves you toward better metabolic health. I try to only eat when the sun is shining, which is another guide to follow that helps you stick to a natural overnight fasting routine.

5. P: Plan ahead

Don’t get caught starving without a meal or snack planned. This week, map out your meals. You can pick and choose or use the 12 Weeks to a Sharper You workbook to fill in your own blanks based on the above guidelines.