Also make sure that you know what foods have mostly carbs, fat, and protein, so you can make the right choices. For instance, it’s not just bread, pasta, chips, cookies, candy, and ice cream that contain carbs. Beans may contain protein, but they’re also very high in carbohydrates. Fruit and veggies also mostly contain carbs. The only foods that don’t contain carbs are meat (protein) and pure fats, like butter and oils (including olive oil and coconut oil).

Focus on exercise: The most compelling studies favor physical activity for mental acuity, says Gary W. Small, M.D., the director of the UCLA Longevity Center and a coauthor of The Alzheimer’s Prevention Program ($14, A study from the Annals of Internal Medicine found that people who were fitter at midlife had a 36 percent lower risk of developing dementia later in life than did their less-fit peers. “When people exercise, the areas that control memory, thinking, and attention increase in the brain,” says Small. “Regular exercisers also have less of the abnormal protein deposits in the brain that have been linked to Alzheimer’s.” That’s not to say that diet has no impact, says Small: “It’s just that the effects of exercise are more pronounced based on the evidence we have now.” Foods rich in omega-3 fatty acids (such as fish, nuts, and flaxseed) and antioxidant-rich fruits and vegetables (like strawberries and spinach) have been shown to improve brain health, while refined sugars and processed foods can have the opposite effect.
When you eat foods high in carbohydrates and fat, your body naturally produces glucose. Carbohydrates are the easiest thing for the body to process, and therefore it will use them first – resulting in the excess fats to be stored immediately. In turn, this causes weight gain and health problems that are associated with high fat, high carbohydrate diets (NOT keto).
Fiber aids digestion, prevents constipation, and lowers cholesterol -- and can help with weight loss. Most Americans get only half the fiber they need. To reap fiber's benefits, most women should get about 25 grams daily, while men need about 38 grams -- or 14 grams per 1,000 calories. Good fiber sources include oatmeal, beans, whole grain foods, nuts, and most fruits and vegetables.