As we approach the new year, nutrition and dieting are hot topics. Many people have put on a few pounds over the holiday season and want to lose it, or they are seeking to finally lose the extra weight they’ve been carrying around for years. There are also lots of other reasons to follow a particular diet. Some people want to go all organic, some people will only eat local, some people follow traditional diets and cut out all processed foods, and still others are seeking healing from intestinal problems and food allergies. It’s been said that nutrition gets people as passionate as religion. Everybody thinks they’ve got the perfect way to eat, and it’s hard to argue with them otherwise. I think there are different ways of eating that work for different people, dependent on your goals, your desires, and your own unique biochemistry. In the next few posts, I’d like to try and demystify some of the science behind nutrition. My ultimate goal is to help you understand what your body needs so you can figure out the best plan for you, otherwise you may be left following the advice of your neighbor down the street who lost 40 pounds on grapefruit and coffee. (Not ideal, just in case any of you were wondering!)
One of the best ways to understanding what your body needs is to to take a look at your pancreas. Yep, that lowly, lumpy, weird shaped organ just may hold the keys to this year’s swimsuit season. It’s not just important for diabetics, and it’s a lot smarter than you think. We’ll start this discussion by examining two of the main hormones of the pancreas: glucagon and insulin.
Glucagon is a mobilization hormone. When your blood sugar drops, glucagon is secreted in order to protect your body from the dangers of low blood sugar. With low enough blood sugar, your brain can’t function, your heart stops, and the end result is death. Glucagon sends signals all throughout the body that there is a critical energy shortage. (In my mind, glucagon is a guy in a hard hat pulling a lever on the wall that sets off flashing red lights and a really annoying alarm. What can I say, I’m a visual person.) The liver starts breaking down stored forms of glucose, and your adrenal glands release cortisol to start breaking down your muscles to rapidly produce glucose and bring your sugar levels back up. You’ve probably felt that jittery feeling after going too long without eating. That’s your body going into a stress response, trying to maintain functions with a limited energy supply. But its not just for emergencies. Glucagon in small amounts also keeps your body fueled through the night when you go for a prolonged period of time without eating.
Insulin, on the other hand, is a storage hormone. It’s what allows the cells of your body to actually take nutrients in and use them for energy. When you eat a lot of carbohydrates, your pancreas wants to protect your brain from the insult of high glucose levels. Insulin gets secreted to store those carbohydrates in the cells, thus keeping your blood sugar levels within an acceptable range. It also stimulates your liver to make glycogen, which is stored for later use when you need more energy for exercise or have a lower glucose intake.
When you eat a balanced meal, with some protein, some fats, and some carbohydrates, these hormones are balanced. There’s enough carbohydrates to provide your body with its immediate fuel needs, and enough protein and fats to use for stored energy and other bodily functions like making enzymes and hormones, and carrying on the work of tissue maintenance and repair.
The problem lies in eating an imbalanced meal. Say you have a big bowl of pasta, without any protein. The carbohydrates start entering the blood stream, and the body senses that the blood sugar is about to go up, way up. Insulin is secreted by the pancreas, which signals all the glucose to go running into the cells and out of the blood stream. Your brain is protected by the quick thinking of your pancreas. But wait….where’s the protein and fat? Without something to sustain you for the long haul, to provide a source of long term stored energy, blood sugar goes below normal levels because of the high insulin response. Sensing its mistake, the pancreas releases glucagon, but by now the adrenals are alerted to the hypoglycemia and start pumping out cortisol. You feel fatigued and jittery, and start craving carbohydrates to bring your blood sugar back up. And so the cycle continues.
Now lets consider the opposite extreme. You believe that your body can run fine without carbohydrates, so you severely limit or even eliminate them completely from your diet. You eat a high protein, high fat diet instead. Your pancreas detects the low levels of incoming glucose, and releases glucagon to provide that critical level of fuel for the brain and other organs. Because low blood sugar will kill you a whole lot faster than high blood sugar will, your body goes into an extreme stress response. Cortisol is released, muscles are broken down, and everything is up for grabs in your body’s fight to maintain its critical glucose levels.
This all makes a whole lot more sense if you view it from an evolutionary medicine perspective. Our bodies were designed for survival. While those of you reading this blog probably don’t struggle with starvation and food scarcity, that’s a relatively new development. For as long as mankind has existed, the availability of food has been less certain and its acquisition often a painful struggle. Our pancreas reacts to low blood sugar in survival mode, not knowing that we could make the choice to walk to the fridge and get an apple and peanut butter for a snack. It’s also used to more complex foods. Traditionally, sweet foods were a bit more complex than they are now. Sweetness primarily came from fruits, complete with lots of fiber and complex carbohydrates that made for a more even release of glucose into the blood stream. With today’s highly processed, highly refined sweets and simple carbs, glucose hits the blood stream like a fire hose, and the body doesn’t know that there’s nothing behind it to keep that glucose from being suddenly cut off. Thus, an overproduction of insulin.
Whew, that was a lot! If any of you are still reading at this point, thanks for sticking with me! I promise once we lay down some of the basics we’ll get into the more interesting stuff. I’d appreciate any feedback about whether you loved this post, hated it, found it easy to understand, or even just plain boring. Next week we’ll tackle the macronutrients themselves: proteins, fats, and carbohydrates. Until then, have a happy New Year!