Thrive: The Vegan Nutrition Guide to Optimal Performance in Sports and Life

only a certain amount of stress; there is a finite amount it can cope with. Strain beyond that point manifests itself in various ways. The first indications that the body is stressed beyond its ability to cope are relatively mild: fatigue, sleep disturbances, and mental fog. If stress overload is more severe, significant weight gain, intense food cravings, and depression become the telltale signs that stress has overwhelmed the system. If these symptoms are not dealt with, if they are allowed to become chronic, the chances of developing a disease such as type II diabetes, fibromyalgia, or even cancer greatly increase.
     

nutrition and cognitive ability
     
    It continually surprises me how little credence many people place on nutrition’s role in achieving and sustaining mental health. As I discuss in Chapter 2, the impact of high-quality food on the reconstruction of cellular tissue cannot be underestimated. The quality of this reconstruction is heavily dependent on the building blocks we make available—as with all other body parts, the brain is sustained and nourished by the food we eat. Constantly orchestrating countless calculations and assessments in just milliseconds, the brain is responsible for keeping us safe. It is in our best interest to keep it healthy.
     
    Amino acids, found in unrefined protein, are our body’s prime construction foods. Essential fatty acids are also vital for healthy brain construction and function. Glucose and fructose, two sugars found in fruit, are the brain’s preferred source of fuel. I discuss all these nutrients later in the book.
     
    Another important role nutrition plays in brain function involves our blood cells. Our blood cells serve several purposes, including distributing nutrients throughout the body and aiding digestion. Although many parts of the body require blood to function properly, blood is drawn to the part of the body where it is needed most. When we eat poorly digestible refined foods, extra blood is drawn to the stomach to help digestion. Because the blood is drawn away from parts that also require it, other bodily functions are slowed. You may have noticed after eating a large, heavy meal that your energy dwindles, that your body slows down. Try concentrating on something that requires considerable thought—it’s difficult. The brain cannot get the blood it needs to function optimally. Not enough blood in the head means not enough nutrients to the brain, and since red blood cells carry oxygen, a heavy meal deprives the brain of oxygen as well. It’s no wonder people have trouble concentrating after a big meal. In Spain, it is common to take a nap after lunch. Lunch is that country’s heaviest meal of the day. The Spanish don’t fight it; they know the body needs to work hard to digest, so they give themselves a break and allow themselves time to recharge. One of the benefits of eating whole, unrefined foods, like those featured in the Thrive Diet, are their low impact on the digestive system and other biological functions. Those who eat according to the Thrive Diet will have a greater ability to think clearly after consuming a meal.
     

cravings
     
    One reason why people become overweight is because they eat too much of the unhealthy types of fat. Why do people crave fat? Fat helps numb the receptors in the brain that regulate emotional responses; that is, eating foods high in fat will help diminish certain unwanted feelings—at least in the short term. The best way to stop fat cravings is to eliminate the cause of the sadness, and that’s easiest done once mental and physical well-being is achieved. The Thrive Diet meal plan will get you on your way.
     
    Too much stress can result in depressed, low moods. In response, the ever resourceful brain attempts to self-medicate. Cravings are the first sign of this. To understand why our brain behaves this way, we again need to look to our primitive roots, to a time when forms of sugar could be found only in nutrient-rich fruit. Early humans craved sweet foods, just as we do, yet these cravings were satisfied exclusively by eating fruit. When stress goes up, so does our need for high-quality nutrition. Fruit provided it for early humans: The brain “assumed” that sweet meant nutrition in the form of fruit. However, most sweets that people eat today—in the form of refined carbohydrates and processed sugars—are nutritionally empty.
     
    A sweet tooth also helps us maintain a positive outlook: