Friday, November 19, 2010

The Nutrition Debate #2: Nutrition 101: A Primer on the Fundamentals of Nutrition

Food has three principal nutrients. They have been designated the Macronutrients. They are: Fat, Protein and Carbohydrate (hereinafter sometimes referred to as “carbs”). Essentially, all of the energy (measured in calories) derived from food comes from these three components.

Foods also have non-caloric nutrients, namely vitamins and minerals, called Micronutrients, as well as water and ash. In addition, foods have important but not yet well understood (or even discovered) Phytochemicals, such as antioxidants, whose benefits are believed vital, indeed essential, to our health and well being.

The energy content of either a gram of protein or a gram of carbohydrate is four (4) calories. The energy in a gram of fat is nine (9) calories, thus making it more than twice as “dense” in calories as either protein or carbs. A gram of ethyl alcohol (ethanol) in an alcoholic beverage contains seven (7) calories but alas no nutrient value.

The 97 calories in a 1 ½ ounce jigger of spirits (vodka, gin, scotch, etc.) are 100% ethyl alcohol. These are indeed “empty calories,” whereas the 119 calories in a 5 oz. glass of white wine are about 90% alcohol and 10% carbs (red wine: 122c./88%/12%). The 146 calories in a 12 ounce regular Budweiser are 67% alcohol, 29% carbs and 4% protein, while the 96 calories in a 12 ounce Michelob Ultra are 85% alcohol, 11% carbs and 3% protein. So, drink beer and wine -- for energy!

Most “sugar-free” candies and “energy bars” contain “sugar alcohol,” which does not elevate blood sugar levels (making them tempting to diabetics). They are, however, not carb-free or calorie-free!

The total available energy of a food is therefore the sum of the products of the weight (in grams) times the calories per gram of the macronutrients of which it is comprised. Fortunately, there are lots of software programs and books (including a USDA database: (www.nal.usda.gov/fnic/foodcomp/search/) that could do all this work for us, so no math is necessary to know how many grams or how many calories of each macronutrient, or the total potential energy (in calories), are contained in a portion of food. Suffice it for this primer to establish an understanding of this basic science.

To that end you should, I think, if you are interested in healthy eating and a long life, be interested to know the macronutrient distribution and balance of your diet. It was not so in the Paleolithic Era, referenced in the 1st installment of this tract. It was then just about survival. It should be noted, though, that it was by “survival of the fittest” and “natural selection” that we “learned” what we needed to eat to enable our survival and evolutionary development. Obviously, from the point of view of an individual’s survival, heuristic learning (by trial and ERROR) is a tough way to learn what to eat!

Half a century ago, in the U. S., some big-government advocates apparently thought so. That’s when politicians and public health officials got involved in establishing nutrition standards (and later, Dietary Guidelines) for Americans. The HHS/USDA is the purveyor of the current U. S. standard. It is represented by the “Nutrition Facts” panel that is required by them to be on all manufactured and processed food packages. It states: “Percent Daily Values are based on a 2,000 calorie diet.” Within the Nutrition Facts panel it also states the percentages for each Macronutrient that one “portion” of that food contains. In addition, it states the percentages for the various sub-classes of Fat (saturated, monounsaturated and polyunsaturated and trans fats) within Total Fat, and also the sugar and fiber (if any) within Carbohydrates. Further, the manufacturer is required to provide percentages for Cholesterol and Sodium, as well as for two (2) minerals and two (2) vitamins. Some manufacturers add percentages for other ingredients as well.

Of course, you cannot have a percentage of something without having a 100% value for it; therefore, it follows that the HHS/USDA has established that value and by extension the “standard” that has become known today as the “Standard American Diet” (unfortunately, SAD, for short). In the SAD, if you do the math, you will see that the minimum “percent daily value” (no longer “Recommended Daily Allowance”) for carbs is 300 grams (times 4 calories per gram = 1,200 calories, or a whopping 60% of a 2,000 calorie diet). The “daily value” for protein is 50g (x 4 = 200 calories or 10% of 2,000). And the “daily value” for fat is 65g (x 9 = 585 calories or +/- 30% of a 2,000 calorie diet. Add it up: 60%+10%+30% = 100% and 1,200 + 200 + 585 calories = 1,985, rounded to 2,000 calories. Note that there is no government “percent daily value” for sugar on the panel, whereas there is a standard for saturated fat. Hmmm…

This means that our government currently recommends that Americans eat a diet comprised of 60% carbohydrates (all of which break down to sugars in the blood, i. e. glucose), with unlimited sugars within that 60%, all this while enjoining us to avoid eating fats, especially saturated fats. Simultaneously, during the same 40 to 50 years, most of us have become fatter, and many of us are becoming (or have become) Type II diabetics (like me). There is, or if not, ought to be, therefore, a raging debate on the subject of nutrition, as we see the increasingly obese population all around us, and hear about the emerging “diabetes epidemic.” I will have more to say on this debate in the next and future installments, but first, I want to say a word to exculpate the average beleaguered physician with a clinical practice.

For over 50 years (longer than the entire time that virtually any doctor still in practice has been in practice), the prevailing wisdom passed down from the powers-that-be has wavered but little. The sources of information that the medical practitioner has relied on are, writ large, our public health officials and, in particular, the practitioner’s medical community, through their specialty practice standards, medical journals and conventions, and the ubiquitous pharmaceutical salesperson. For the most part, practicing physicians were not trained much (if at all) in nutrition, except for basic biochemistry; they have had little time to “bone up” on an area that isn’t being pushed by big pharma. And, finally, the nutrition field, especially the basic science with which the clinical practitioner has less interest and exposure, has advanced very dramatically in the last twenty years. So, I do not blame them. I sympathize with (most of) them. They are stuck in the status quo of the mainstream message and, like the government, are “committed” and unable to turn around, or even waver, in the face of compelling and mounting evidence.

This suggests to me that it may be time for the patient to assume responsibility and take charge of his (or her) own health, from a dietary point of view. In the next installment, I will tell you how I think we got to be in this place. It’s an interesting story.

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