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I ran across the following section in a biochemistry text on my bookshelf today and thought I would post it in the science section here at DH to see if people would like to dissect it. No footnotes/endnotes where given for the claims. I've enumerated them below for discussion.From page 585, chapter 18"A Fad Diet--Low Carbohydrates, High Protein, High FatPossibly the most serious nutrition problem in the United States is excessive food consumption, and many people have experimented with fad diets in the hope of losing excess weight. One of the most popular of the fad diets has been the high-protein, high-fat (low-carbohydrate) diet. The premise for such diets is tantalizing: because the tricarboxylic acid (TCA) cycle (see Chapter 20) is the primary site of fat metabolism, and because glucose is usually needed to replenish intermediates in the TCA cycle, if carbohydrates are restricted in the diet, dietary fat should merely be converted to ketone bodies and excreted. This so-called diet appears to work at first because a low-carbohydrate diet results in an initial water (and weight) loss. This occurs because glycogen reserves are depleted by the diet and because about 3 grams of water of hydration are lost for every gram of glycogen. However, the long-term results of this diet are usually disappointing for several reasons. First, ketone body excretion by the human body usually does not exceed 20 grams (400 kJ) per day. Second, amino acids can function effectively to replenish TCA cycle intermediates, making the reduced carbohydrate regimen irrelevant. Third, the typical fare in a high-protein, high-fat, low carbohydrate diet is expensive but not very tasty, and it is thus difficult to maintain. Finally, a high-fat diet is a high risk factor for atherosclerosis and coronary artery disease."- Biochemistry, Reginald H. Garrett and Charles M. GrishamFrom the last paragraph:1. ketone body excretion by the human body usually does not exceed 20 grams (400 kJ) per day2. amino acids can function effectively to replenish TCA cycle intermediates, making the reduced carbohydrate regimen irrelevant3. the typical fare in a high-protein, high-fat, low carbohydrate diet is expensive but not very tasty, and it is thus difficult to maintain4. a high-fat diet is a high risk factor for atherosclerosis and coronary artery disease
Here are my preliminary thoughts.1. ketone excretion is not a necessary requirement for ketogenesis (see ketosis vs. ketogenesis)2. I don't know the rates for gluconeogenesis. How big of an issue is this for those in training? Can gluconeogenesis really keep up?3. This seems to be more a matter of opinion and has no place in a scientific discussion on metabolism in my opinion (okay, maybe compliance is a factor for prescription diets, but less so for people self-motivated by health and performance goals)4. "risk factors" are usually developed from correlative studies. Garrett and Grisham are not epidemiologists, so I assume they got this information from someone else. Without any citations for this section of the text, it is hard to say. High fat/low carb vs high fat/high carb diets may present very different correlative statistics with respect to atherosclerosis and coronary artery disease. Does anybody have a "go to" study for this?Cheers.Honestly i don't think DH falls into this category due to many variables put in place.I think a lot of the fad diets, referred to as low-carb are diets, still say that you can consume carbohydrates regularly, just at a lower amount each day; with CNS or CBL that is not the general consensus. CNS is an ultra low carb diet, it provides a refeed schedule to sort of reset the fat burning hormones to more optimal and reduce the amount of insulin spikes throughout the day. Also it increases insulin sensitivity over a longer period, which is the opposite of insulin resistance. Health benefit? Also, define high fat: that's all relative to the individual. Also, a lot of us do .5:1 gram fat to protein, which doesn't equate to a whole lot of fat.Managing your blood sugar and hormones is the name of the game (which CNS helps with).... just ask your parents or your grandmother how important it is while they are checking their blood glucose and shooting up insulin 6 times a day!
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