Gabriel Guzman
06-16-2006, 11:19 AM
Arguably, one of the most common and traditional criticisms of a carbohydrate-controlled diet is the lack long-term studies. Even when the results fly in the face of researchers that have designed studies to test the efficacy of such diets, sometimes with a starting bias against it, only to find out that they do work, their discussion segment of their published papers always contains phrases like this: “…more work needs to be done…”
As Arora and McFarlane explain in their article “The case for low carbohydrate diets in diabetes management (http://www.nutritionandmetabolism.com/content/2/1/16)”, the same “more work needs to be done” caveat is also true of the assumed standard low fat diets which “have an ambiguous record at best” (Arora & McFarlane, 2005).
Although this article is almost a year old, I still recommend those who would like to read about different scenarios in which a carbohydrate-controlled diet has been shown to improve health. The article does go a little technical in some parts but in general, it does present a glance of the research being done in which carbohydrate control has proven its efficacy against the standard low-caloric, fat-restricted approaches tried thus far with little or no result as far as combating the epidemic of metabolic maladies that afflict a large portion of the population of this and other countries.
The article does have a small caveat, which is not really surprising if you think that sometimes peer reviewers need to be ‘pleased’ somehow if one wants to get anything published. There is mention of the reduction of carbohydrate intake to less than 30 g/day as being ‘extreme’ and, of course, the authors suggest that such diets cannot be recommended for a diabetic population at this time without further study. Perhaps their opinion has changed now after more data has been published. Other than that, I think it is a very informative article worth keeping in our archives. You can download the PDF file here: http://www.nutritionandmetabolism.com/content/2/1/16, or from the “Important Link and Resources (http://72.32.36.211/forum/showthread.php?t=68)” under the Getting Started area of the board.
Some points that I thought worth discussing are:
There is no clear cut definition of a low carbohydrate diet in the literature. True, my interpretation of what a ‘low-carbohydrate’ diet is differs from, say Rachel Ray’s. For some, just a modest reduction in their consumption of sugar, bread and sweets is already a ‘low-carbohydrate’ diet. For others, only a zero-, no-carbohydrate-at-all constitutes a ‘low-carbohydrate diet'. The authors, however, distinguish between moderate but significant reduction in carbohydrates (which they call LoCHO), and very low carbohydrate ketogenic diets (or VLKD) with ‘extreme’ reductions to less than 20 or 30 g/day as in the early phase of various popular diets. Here they cite the Atkins, South Beach and Protein Power diets. There is a point here: there is no clear cut definition of what ‘low-carbohydrate’ is; there is no consensus among the researchers of what ‘low-carbohydrate intake’ should be.
We can actually calculate how much is truly needed to supply those cells that are obligatory glucose consumers (red blood cells and some, not all, brain cells). I’m not going to do that here but the breakdown shows something in the vicinity of 30-50 g per day that really ends up in those tissues and is used. More than that, unless there is an immediate energetic demand, is converted into something else for later. That alone should serve as a guideline to define what we mean by ‘dietary carbohydrate requirement’. Another problem is that we’re still stuck in the calorie hole and recommendations are made based on caloric needs, which in turn assume that most of the energy should come from carbohydrate burning, which in turn overestimates the amount of calories a person of a certain size needs. If that person is actually a fat burner, the formulae and numbers involved in the estimation are not the same but no one seems to either know that fact or pay attention to it.
Perhaps a better way to refer to what we call ‘low-carb’ diets should be either ‘lower’ or ‘carbohydrate-controlled’. I prefer the latter because if we throw individual variables, such as exercise (and the type of exercise), lean body mass, etc., then what could be ‘low’ for one individual may still be ‘high’ for another one that doesn’t exercise as much. One thing remains clear, though; anything that falls under the current 250-300 gr of carbohydrate recommended by the medical, nutritional and dietetic establishment should be call ‘lower-carb’. In my opinion, a structured approach with specific amounts not just ‘eye-balling’ estimation of carbohydrate content qualifies for a ‘carbohydrate-controlled’ approach and that is why I always refer to a ‘low-carb’ diet as a ‘carbohydrate-controlled’ diet.
The authors also make a connection between the reduction of carbohydrate and an automatic increase in fat intake as ‘a must’ in what they describe the popular low-carb diets. Unfortunately, this not only shows me that while they may have read Atkins and perhaps South Beach Diet, they definitely didn’t read Protein Power. Also unfortunate is the fact that Protein Power, which distinguishes itself from other approaches precisely because of it’s balanced approach regarding protein and fat, is just dumped into the same ‘low-carb sac’ when researchers try to make a point.
Finally, it’s not uncommon to find out that when researchers try to study the effects of a carbohydrate-controlled diet, they don’t consider the amount of fiberin the food they choose for their studies. Think of a study that describe that the subjects eat a low-carb diet consisting of 50 g/day of CHO. Very rarely, they explain if that is actually ‘effective carbohydrate’ or is ‘total carbohydrate’ (i.e. fiber included). As we all know here, there is a huge difference between 50 g ECC and 50 g of total CHO. To me this is important because one of the common parameters that is measured is ‘compliance’. Fifty grams of fiber-rich food (which normally contains little effective CHO) doesn’t have the same volume as 50 g of ECC-food. As we’ve all experienced on Protein Power, if we choose our carbohydrate source from green-leafy, non-starchy, fiber-rich vegetables, the actual amount of those foods in our plate that actually make 50 g ECC is not ‘small potatoes’, no pun intended! And in terms of signals that trigger satiety, besides the signals from protein-rich food themselves, the volume provided by those ‘low-ECC’ foods helps to curb hunger and keeps us from eating between meals, which in turn has a positive effect in compliance. I’ve asked that question several times during lectures from somebody showing their nice data bout the efficacy of low-carb diets but also mention that sometimes there is low compliance because people feel hungry too often. Their answer is that they did not consider fiber content but total carb. In my mind, that explains a lot!
Low carbohydrate diets and weight loss. One of the most common findings in any study is that weight loss in the range of 5-10% of the initial weight improves a lot of things, including glycemic control, hyperinsulinemia, inflammatory markers, you name it. The way in which weight is lost, however, I believe is also important because it’s not the same to lose weight from everywhere, including muscle mass or lose weight only from fat and there is where nutritional composition plays a key role. Nonetheless, modest weight loss has been shown to be effective in preventing the development of diabetes in a high risk population, as Arora & McFarlane cite in their review. The authors make a valid point when they mention that, despite the traditionally accepted dogma that the root of all evil in terms of the obesity epidemic has been an increased fat consumption (the lipid hypothesis no less), the trends in food intake during the obesity epidemic do not support that notion. We’ve all seen the statistics on this matter (from reading Protein Power) and other material we’ve discussed on this board. The bottom line is that fat consumption hasn’t increased but decreased and carbohydrate intake has increased simultaneously. Incidentally, a few years back I challenged this notion when attending to a lecture. The speaker actually acknowledged that the trend in fat consumption had decreased, according to the data, but she still asked the audience ‘…but is that really true?’ and in support of her hidden statement, she flashed pictures of hamburgers, pizza, fried chicken, subs… Then I asked, but those foods come with a hefty amount of carbohydrates too, don’t they?. There was no response. In fact, a breakdown of the nutritional data of any of those foods spits out a significant amount of starch, sugar or high-fructose corn syrup. That still happens every day. Just ask anyone you know to mention ‘fatty’ foods and they will mention foods that do contain fat but the amount of carbohydrate is not to be neglected… but that escapes most people.
There is a disconnect between nutritional composition and carbohydrate-control when researchers try to study the latter in the context of weight loss. The reason? They are still stuck in the calorie-hole. In their review, the authors write “weight change is governed by two factors: caloric balance and macronutrient composition”. Strictly speaking, there are other factors that are involved in weight change but I think that the way they wrote it is an easier way to understand without getting matters too complicated. The traditional approach to weight loss has rested in caloric balance alone because the accepted dogma is that since fat is the more caloric dense nutrient, then its reduction should achieve significant caloric deficit to induce weight loss. Half true… It does cause a caloric deficit and it may induce weight loss but at the expense of other detrimental outcomes, such as loss of muscle mass, vitamin deficiencies, worsening of lipid profiles, to mention just a few. The reason, again, is the al mighty calorie-is-a-calorie concept that can’t be more wrong when applied to human metabolism. If nutritional composition is considered, then weight loss occurs without detrimental effects and that is what carbohydrate-controlled diets have been showing over the years. In fact, it’s amazing that given the fact that researchers still don’t really understand what carbohydrate-control really is, they still manage to show its efficacy to manage, control and reverting conditions such as hyperglycemia, diabetes, hypercholesterolemia, and obesity. In my opinion, carbohydrate control diets, in which nutritional composition is considered, work for weight loss because they 1) provide an optimum metabolic scenario in which caloric deficit can take place, 2) provide the appropriate nutritional composition to make sure that it is fat that’s being loss during the weight loss period. Besides caloric deficit, there is also a shift in the way calories per se are used. Here is where the calorie is a calorie concept fails so sadly because the data shows that when compared to typical low-calorie (low fat) diets, carbohydrate-controlled diets may not really lower in calories, yet achieve higher weight loss. That actually suggests that weight loss may depend a lot more on nutritional composition than just reducing carbohydrate intake. The reason may be the amount of protein in the diet, which available data suggests that affects metabolism in many ways, including higher thermogenesis, higher satiety and of course, preservation of lean body mass, something that carbohydrate control alone cannot achieve.
In the next installment, I'll continue with other points of discussion, including low-carbohydrate diets and glycemic control, lc-diets and dyslipidemia and other points covered in the review. Until then, I hope your eyes are not yet too crossed!!!:eek:
As Arora and McFarlane explain in their article “The case for low carbohydrate diets in diabetes management (http://www.nutritionandmetabolism.com/content/2/1/16)”, the same “more work needs to be done” caveat is also true of the assumed standard low fat diets which “have an ambiguous record at best” (Arora & McFarlane, 2005).
Although this article is almost a year old, I still recommend those who would like to read about different scenarios in which a carbohydrate-controlled diet has been shown to improve health. The article does go a little technical in some parts but in general, it does present a glance of the research being done in which carbohydrate control has proven its efficacy against the standard low-caloric, fat-restricted approaches tried thus far with little or no result as far as combating the epidemic of metabolic maladies that afflict a large portion of the population of this and other countries.
The article does have a small caveat, which is not really surprising if you think that sometimes peer reviewers need to be ‘pleased’ somehow if one wants to get anything published. There is mention of the reduction of carbohydrate intake to less than 30 g/day as being ‘extreme’ and, of course, the authors suggest that such diets cannot be recommended for a diabetic population at this time without further study. Perhaps their opinion has changed now after more data has been published. Other than that, I think it is a very informative article worth keeping in our archives. You can download the PDF file here: http://www.nutritionandmetabolism.com/content/2/1/16, or from the “Important Link and Resources (http://72.32.36.211/forum/showthread.php?t=68)” under the Getting Started area of the board.
Some points that I thought worth discussing are:
There is no clear cut definition of a low carbohydrate diet in the literature. True, my interpretation of what a ‘low-carbohydrate’ diet is differs from, say Rachel Ray’s. For some, just a modest reduction in their consumption of sugar, bread and sweets is already a ‘low-carbohydrate’ diet. For others, only a zero-, no-carbohydrate-at-all constitutes a ‘low-carbohydrate diet'. The authors, however, distinguish between moderate but significant reduction in carbohydrates (which they call LoCHO), and very low carbohydrate ketogenic diets (or VLKD) with ‘extreme’ reductions to less than 20 or 30 g/day as in the early phase of various popular diets. Here they cite the Atkins, South Beach and Protein Power diets. There is a point here: there is no clear cut definition of what ‘low-carbohydrate’ is; there is no consensus among the researchers of what ‘low-carbohydrate intake’ should be.
We can actually calculate how much is truly needed to supply those cells that are obligatory glucose consumers (red blood cells and some, not all, brain cells). I’m not going to do that here but the breakdown shows something in the vicinity of 30-50 g per day that really ends up in those tissues and is used. More than that, unless there is an immediate energetic demand, is converted into something else for later. That alone should serve as a guideline to define what we mean by ‘dietary carbohydrate requirement’. Another problem is that we’re still stuck in the calorie hole and recommendations are made based on caloric needs, which in turn assume that most of the energy should come from carbohydrate burning, which in turn overestimates the amount of calories a person of a certain size needs. If that person is actually a fat burner, the formulae and numbers involved in the estimation are not the same but no one seems to either know that fact or pay attention to it.
Perhaps a better way to refer to what we call ‘low-carb’ diets should be either ‘lower’ or ‘carbohydrate-controlled’. I prefer the latter because if we throw individual variables, such as exercise (and the type of exercise), lean body mass, etc., then what could be ‘low’ for one individual may still be ‘high’ for another one that doesn’t exercise as much. One thing remains clear, though; anything that falls under the current 250-300 gr of carbohydrate recommended by the medical, nutritional and dietetic establishment should be call ‘lower-carb’. In my opinion, a structured approach with specific amounts not just ‘eye-balling’ estimation of carbohydrate content qualifies for a ‘carbohydrate-controlled’ approach and that is why I always refer to a ‘low-carb’ diet as a ‘carbohydrate-controlled’ diet.
The authors also make a connection between the reduction of carbohydrate and an automatic increase in fat intake as ‘a must’ in what they describe the popular low-carb diets. Unfortunately, this not only shows me that while they may have read Atkins and perhaps South Beach Diet, they definitely didn’t read Protein Power. Also unfortunate is the fact that Protein Power, which distinguishes itself from other approaches precisely because of it’s balanced approach regarding protein and fat, is just dumped into the same ‘low-carb sac’ when researchers try to make a point.
Finally, it’s not uncommon to find out that when researchers try to study the effects of a carbohydrate-controlled diet, they don’t consider the amount of fiberin the food they choose for their studies. Think of a study that describe that the subjects eat a low-carb diet consisting of 50 g/day of CHO. Very rarely, they explain if that is actually ‘effective carbohydrate’ or is ‘total carbohydrate’ (i.e. fiber included). As we all know here, there is a huge difference between 50 g ECC and 50 g of total CHO. To me this is important because one of the common parameters that is measured is ‘compliance’. Fifty grams of fiber-rich food (which normally contains little effective CHO) doesn’t have the same volume as 50 g of ECC-food. As we’ve all experienced on Protein Power, if we choose our carbohydrate source from green-leafy, non-starchy, fiber-rich vegetables, the actual amount of those foods in our plate that actually make 50 g ECC is not ‘small potatoes’, no pun intended! And in terms of signals that trigger satiety, besides the signals from protein-rich food themselves, the volume provided by those ‘low-ECC’ foods helps to curb hunger and keeps us from eating between meals, which in turn has a positive effect in compliance. I’ve asked that question several times during lectures from somebody showing their nice data bout the efficacy of low-carb diets but also mention that sometimes there is low compliance because people feel hungry too often. Their answer is that they did not consider fiber content but total carb. In my mind, that explains a lot!
Low carbohydrate diets and weight loss. One of the most common findings in any study is that weight loss in the range of 5-10% of the initial weight improves a lot of things, including glycemic control, hyperinsulinemia, inflammatory markers, you name it. The way in which weight is lost, however, I believe is also important because it’s not the same to lose weight from everywhere, including muscle mass or lose weight only from fat and there is where nutritional composition plays a key role. Nonetheless, modest weight loss has been shown to be effective in preventing the development of diabetes in a high risk population, as Arora & McFarlane cite in their review. The authors make a valid point when they mention that, despite the traditionally accepted dogma that the root of all evil in terms of the obesity epidemic has been an increased fat consumption (the lipid hypothesis no less), the trends in food intake during the obesity epidemic do not support that notion. We’ve all seen the statistics on this matter (from reading Protein Power) and other material we’ve discussed on this board. The bottom line is that fat consumption hasn’t increased but decreased and carbohydrate intake has increased simultaneously. Incidentally, a few years back I challenged this notion when attending to a lecture. The speaker actually acknowledged that the trend in fat consumption had decreased, according to the data, but she still asked the audience ‘…but is that really true?’ and in support of her hidden statement, she flashed pictures of hamburgers, pizza, fried chicken, subs… Then I asked, but those foods come with a hefty amount of carbohydrates too, don’t they?. There was no response. In fact, a breakdown of the nutritional data of any of those foods spits out a significant amount of starch, sugar or high-fructose corn syrup. That still happens every day. Just ask anyone you know to mention ‘fatty’ foods and they will mention foods that do contain fat but the amount of carbohydrate is not to be neglected… but that escapes most people.
There is a disconnect between nutritional composition and carbohydrate-control when researchers try to study the latter in the context of weight loss. The reason? They are still stuck in the calorie-hole. In their review, the authors write “weight change is governed by two factors: caloric balance and macronutrient composition”. Strictly speaking, there are other factors that are involved in weight change but I think that the way they wrote it is an easier way to understand without getting matters too complicated. The traditional approach to weight loss has rested in caloric balance alone because the accepted dogma is that since fat is the more caloric dense nutrient, then its reduction should achieve significant caloric deficit to induce weight loss. Half true… It does cause a caloric deficit and it may induce weight loss but at the expense of other detrimental outcomes, such as loss of muscle mass, vitamin deficiencies, worsening of lipid profiles, to mention just a few. The reason, again, is the al mighty calorie-is-a-calorie concept that can’t be more wrong when applied to human metabolism. If nutritional composition is considered, then weight loss occurs without detrimental effects and that is what carbohydrate-controlled diets have been showing over the years. In fact, it’s amazing that given the fact that researchers still don’t really understand what carbohydrate-control really is, they still manage to show its efficacy to manage, control and reverting conditions such as hyperglycemia, diabetes, hypercholesterolemia, and obesity. In my opinion, carbohydrate control diets, in which nutritional composition is considered, work for weight loss because they 1) provide an optimum metabolic scenario in which caloric deficit can take place, 2) provide the appropriate nutritional composition to make sure that it is fat that’s being loss during the weight loss period. Besides caloric deficit, there is also a shift in the way calories per se are used. Here is where the calorie is a calorie concept fails so sadly because the data shows that when compared to typical low-calorie (low fat) diets, carbohydrate-controlled diets may not really lower in calories, yet achieve higher weight loss. That actually suggests that weight loss may depend a lot more on nutritional composition than just reducing carbohydrate intake. The reason may be the amount of protein in the diet, which available data suggests that affects metabolism in many ways, including higher thermogenesis, higher satiety and of course, preservation of lean body mass, something that carbohydrate control alone cannot achieve.
In the next installment, I'll continue with other points of discussion, including low-carbohydrate diets and glycemic control, lc-diets and dyslipidemia and other points covered in the review. Until then, I hope your eyes are not yet too crossed!!!:eek: