Does school lunch bring back memories of scoops of buttery mashed potatoes and greasy chicken drumsticks served with whole milk and a spork? With the national obesity rate on the rise, schools are opting for healthier food choices and are asking parents to do the same. One Kindergarten teacher specifically requested parents to pack snacks with high protein and fiber, since they are best for learning. As graduate students, we can perhaps learn from this advice, as scientific evidence suggests that certain foods support brain function significantly better than others.
I learned this the hard way back in graduate school when I used to fight the mid-afternoon lows with tasty pastries from the local coffee shop. Aside from the unwanted effects of the extra calories, I noticed another disturbing phenomenon. While the sugar and chocolate fueled me for a little while (30-60 minutes), my energy plummeted rapidly afterwards, and I felt moody and hungry again.
Assuming this was the only way to get through the day, I just accepted the consequences of this unhealthy habit. As a senior graduate student I came across a nutrition book which explained the relationship between diet and blood glucose, and how one could regulate their moods and energy levels by eating certain food combinations. The details of the mechanism by which food affects blood glucose could fill an entire textbook chapter, but I will try to summarize it briefly here. So, what is the best food for thought?
Glucose is the preferred fuel source for your brain, and your brain functions best when you have a steady blood glucose level. When simple sugars, such as those found in sweets, and white bread, are consumed by themselves, they will lead to a sudden increase in your blood glucose levels, stimulating your body to releases insulin. Insulin signals the body to store the excess glucose as glycogen in the liver and muscle. Excess glucose will be stored as fat, a consequence most of us would rather avoid. The sudden drop in blood glucose, caused by the release of insulin, will lead to feelings of drowsiness and fatigue.
Does this mean you should not eat carbs? Absolutely not. The secret to maintaining your blood glucose level is to eat complex or mixed meals. A mixed meal includes a balanced combination of proteins, carbohydrates and fats (yes, you need a little bit of fat in your meals, about 30% of your total calories). When your meals are “complex” your blood sugar rises more steadily, and your body will not be stimulated to release insulin so quickly. What are examples of mixed snacks? Try yoghurt with nuts, bread and cheese with vegetables, cottage cheese and fruit, or whole grain cereal with milk.
Where does fiber fit into the picture? As a nutritionist once told me, the fiber content of a food is a signal of how close to nature it is. The higher the fiber content of breads, the less processing they went through. Fiber increases the feeling of fullness, so you will be satiated for longer. Foods with high fiber content, such as whole grain pastas, breads, and cereal bars take longer to break down, and help maintain your blood glucose levels and fuel your brain. When the teacher asked parents to pack snacks with protein and fiber, she certainly knew what she was talking about: weight control and brain food at the same time!