Saturday, July 20, 2013

The Nutrition Debate #127: Fighting Sleep?

“Fighting sleep has become a national pastime,” the headline roars in a November 18th story by syndicated columnist Mitch Albom. And to make the story more topical the lead is, “I have never gulped a 5-hour energy (drink).” Not to be mistaken for a product placement, even the other caffeine-loaded drink, Monster, is mentioned. And, not to neglect the older newspaper-reading demographic, the columnist even mentions popping NoDoz himself in years past. But this opinion piece is not about caffeine drinks, or even about the need for a good night’s sleep, which I don’t dispute. It is about why many people feel sleepy or drowsy a few hours after eating a meal. Let me be clear: I do not, ever, anymore.

The reason why people feel sleepy a few hours after eating a typical meal is physiologic. It is very real. I know because I experienced it frequently myself for most of my life. And it is related to energy, particularly available energy. The body manages homeostasis by summoning energy from available sources. That’s why we eat – to replenish our level of available energy by ingestion, digestion and absorption into the blood stream of nutrients to replace the ones we have used. These are required both to maintain our basal metabolism and to support the activity levels above those requirements. Our body also stores energy for this purpose; however, this stored energy is not always available for use.

There are three macronutrients: protein, carbohydrates and fat. Protein is the only one that does not store energy that can be called upon as a fuel when needed. When protein is digested, it breaks down to amino acids which circulate for 4-5 hours to be taken up by muscle, for repair, and many other uses in the body.  The balance of amino acids, if any, then goes to the liver for storage where they can later be used to synthesize glucose, which is a good thing, generally.

 Carbohydrates (both simple sugars and complex) digest more quickly, in just minutes for highly processed carbs found in most food products in today’s marketplace (especially liquid and refined forms), and just one to two hours for virtually all the rest. All carbohydrates are digested ultimately into single molecule form, almost all of them to glucose, some to fructose, and a few to galactose. When glucose is digested and absorbed, it raises the level of “sugar” in the blood precipitously. Normally, we need just under one teaspoon of sugar in our bloodstream. A meal with 100 carbs is equivalent to 13 teaspoons. Our blood sugar “spikes.” This “quick energy” doesn’t last. The reason many people feel sleepy or drowsy a few hours after eating a meal loaded with carbohydrates is that their blood sugar level “crashes.”

When high levels of glucose are detected in the blood, the body secretes insulin to take it to where it is needed, to the muscles for example. That’s what exercisers call “carb loading.” After replenishing the cells, the balance of circulating glucose goes to the liver to be stored as glycogen. And when the liver gets overloaded with glycogen, especially when it is deluged with a load of liquid sugar (as in soft drinks and fruit juice), it converts the excess to fat by a process called lipogenesis. That’s right; the sugar overload in your soft/juice drink converts to body fat. See

The body does this to protect itself from sugar because the fructose molecule in sugar is toxic when it is over consumed.  That’s why fructose goes straight to the liver. One of the liver’s functions is to detoxify things. The liver then converts the fructose to fat, and some of this fat is stored in the liver. Non-Alcoholic Fatty Liver Disease (NAFLD) is near-epidemic. Fructose is a large part of the food supply. It is 50 percent of table (cane) sugar, 55% of the sweetener HFCS used in soft drinks and 42% in bread and many other processed food products. And fructose is 67% of the sugar in an apple or pear.

Fat, the third macronutrient, is the densest in terms of food energy. It has 9 calories per gram versus 4 for both protein and carbohydrate. This makes it ideal for “long term” storage. The body is designed to “put it away” in storage to make available when needed. But since protein circulates and can be used for its special purpose for only 4-5 hours, and ingested carbohydrates get used for quick energy almost immediately and at most in 1-2 hours, what does our body use for energy after 1-2 hours? The answer is glycogen, the storage form of carbohydrates in the liver and muscles. It will meet our energy needs between meals. We are designed to have enough in storage for that purpose.

What happens when our glycogen storage is exhausted (or non-existent)? Do we have a reliable back-up system? You bet we do. We burn our body fat. This happens every night (14 hours from dinner to breakfast for me), when my body shifts from the “fed” to the “fasting” state. When I am in this ketogenic state, which I strive to be in continuously while I am trying to lose weight, my body burns fat as its primary fuel source. As a consequence, my blood sugars are relatively stable all day long. My blood sugar doesn’t spike after a meal and it doesn’t crash a few hours later. I do not feel sleepy or drowsy between meals. I don’t need to snack for a “pick-me-up.” I do not need 5-hour or Monster or NoDoz or even coffee. Caffeine “treats” the symptom, not the cause of sleepiness. The cause of sleepiness is unstable blood glucose from carb binging and crashing. I have a high, stable energy level all day long. Then I get a really good night’s sleep.
How do you feel after meals?

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