low carb diet has been debunked

DeguelloTex

yarwell wrote: »

DeguelloTex wrote: »

yarwell wrote: »

0.35 seems a reasonable start point, if a little arbitrary and perhaps reminiscent of low fat diets. Combined with another rule of thumb 10 kcal/lb it ends up at ~31.5 %cals from fat.

Are you saying 31% of calories from fat is reminiscent of low fat diets? That number is pretty much right in the middle of most every recommendation I've seen (25-35%). Or am I misunderstanding your point with that comparison?

25-35% is the low / reduced fat diet we're encouraged to eat.

How much fat were we encouraged to eat before we were encouraged to eat 25-35%?

Gianfranco_R

goldthistime wrote: »

yarwell wrote: »

goldthistime wrote: »

it could be argued that the difference in the fat loss for those six days is just that the subjects' bodies found the low fat diet to be more of a metabolic adjustment than the lowish carb diet.

During the six days the restricted carb diet was reducing glycogen reserves and burning carbs other than from food, which reduced the fat burn. By about 8.5 days this would have disappeared and something else would have to replace it - perhaps more fat burning. One the first day 400 cals came from this source

Thanks for your response. Forgive my confusion, I'm not well versed in low carb, but you are saying that while the low fat diet allowed body fat to be burned beginning from day 1, the low carb diet reduced glycogen reserves before any body fat could be burned. Yes? Do you believe that after 8.5 days the weight loss and ratio of fat/lbm henceforth should be roughly equal between the two groups?

For you and any of our other science-y people here, maybe you could help clear up a few questions I had about this study...

To begin with, if you look at Figure 3 H, the graph is meant to represent a prediction of what would happen after six months. As the carb level approaches zero (probably 5%?), the weight loss is predicted to be around 17kg for the low carb (RC) group, whereas the low fat (RF) group is shown to have a predicted weight loss of around 10 or 11kg. I thought we all agreed that after a certain point the two methods should converge and it becomes just about calories in/out again. The authors of this study really believe that there would be over a 5kg difference for two diets identical in CICO?

That same graph shows that after six months the fat mass loss for RC group would be as low as 7.5kg, where the fat mass for the RF group would be about 10kg. This means that the RF group lost ONLY fat, no LBM whatsoever. Cool. Seems hard to believe though. Looking at a 25% carbs level, an individual is predicted to have lost around 8kg of fat and 15kg of total weight. I recall reading that depleting glycogen reserves reduces water weigh too, but not to the tune of 7kg.

If the answer is that the authors are extrapolating the results, no matter how inaccurate, why bother including grossly misleading charts?

The author states that DXA tests did NOT show a significant difference in fat loss between the two groups at the end of six days. I thought DXA was the gold standard in measuring fat loss. How sure are we that Hall's method of measuring fat loss is reliable?

"One female subject had changes in DXA % body fat data that were not physiological and were clear outliers, so these data were excluded from the analyses" Not physiological? I don't get it. Did she have liposuction while in that chamber? Why not tell us which group she was in?

I actually have a ton more questions, but if I'm alone in enjoying the process of looking at this study in detail I won't bother asking more.

Well, if anything, this study has "debunked" the "a calorie is a calorie" dogma. Anyway, they also notice that: while the present study demonstrated the theoretical possibility that isocaloric diets differing in carbohydrate and fat can result in differing body fat losses, the body acts to minimize such differences.

goldthistime

Gianfranco_R wrote: »

goldthistime wrote: »

yarwell wrote: »

goldthistime wrote: »

it could be argued that the difference in the fat loss for those six days is just that the subjects' bodies found the low fat diet to be more of a metabolic adjustment than the lowish carb diet.

During the six days the restricted carb diet was reducing glycogen reserves and burning carbs other than from food, which reduced the fat burn. By about 8.5 days this would have disappeared and something else would have to replace it - perhaps more fat burning. One the first day 400 cals came from this source

Thanks for your response. Forgive my confusion, I'm not well versed in low carb, but you are saying that while the low fat diet allowed body fat to be burned beginning from day 1, the low carb diet reduced glycogen reserves before any body fat could be burned. Yes? Do you believe that after 8.5 days the weight loss and ratio of fat/lbm henceforth should be roughly equal between the two groups?

For you and any of our other science-y people here, maybe you could help clear up a few questions I had about this study...

To begin with, if you look at Figure 3 H, the graph is meant to represent a prediction of what would happen after six months. As the carb level approaches zero (probably 5%?), the weight loss is predicted to be around 17kg for the low carb (RC) group, whereas the low fat (RF) group is shown to have a predicted weight loss of around 10 or 11kg. I thought we all agreed that after a certain point the two methods should converge and it becomes just about calories in/out again. The authors of this study really believe that there would be over a 5kg difference for two diets identical in CICO?

That same graph shows that after six months the fat mass loss for RC group would be as low as 7.5kg, where the fat mass for the RF group would be about 10kg. This means that the RF group lost ONLY fat, no LBM whatsoever. Cool. Seems hard to believe though. Looking at a 25% carbs level, an individual is predicted to have lost around 8kg of fat and 15kg of total weight. I recall reading that depleting glycogen reserves reduces water weigh too, but not to the tune of 7kg.

If the answer is that the authors are extrapolating the results, no matter how inaccurate, why bother including grossly misleading charts?

The author states that DXA tests did NOT show a significant difference in fat loss between the two groups at the end of six days. I thought DXA was the gold standard in measuring fat loss. How sure are we that Hall's method of measuring fat loss is reliable?

"One female subject had changes in DXA % body fat data that were not physiological and were clear outliers, so these data were excluded from the analyses" Not physiological? I don't get it. Did she have liposuction while in that chamber? Why not tell us which group she was in?

I actually have a ton more questions, but if I'm alone in enjoying the process of looking at this study in detail I won't bother asking more.

Well, if anything, this study has "debunked" the "a calorie is a calorie" dogma. Anyway, they also notice that: while the present study demonstrated the theoretical possibility that isocaloric diets differing in carbohydrate and fat can result in differing body fat losses, the body acts to minimize such differences.

So their conclusion is that "the body acts to minimize such differences" so ignore the six month extrapolations? Meh, maybe I have just misread something. To your point though, that "a calorie is a calorie" has been debunked, I read this statement recently...

"If you have 100 extra calories in fat (about 11 grams) floating in your bloodstream, fat cells can store it using only 2.5 calories of energy. On the other hand, if you have 100 extra calories in glucose (about 25 grams) floating in your bloodstream, it takes 23 calories of energy to convert the glucose into fat and then store it. Given a choice, a fat cell will grab the fat and store it rather than the carbohydrates because fat is so much easier to store."

It agrees with the results of the study, that calorie for calorie, a low fat diet should result in more fat loss.

But having read so many studies that give low-carb diets an edge over low-fat in real life situations, I have to conclude that there is more to the story. Satiety and thus willingness to adhere might be all there is to it.

daniwilford

Sunny_Bunny_ wrote: »

daniwilford wrote: »

I think there should be a distinction between low fiber carbs and moderate high fiber carbs. High fiber carbs react totally different in body. Most of the benefits of carbs come in forms with high fiber and most of the negatives of carbs come in forms where the fiber stripped away. I think any discussion about carbs verses fats in dietary nutritional context should include the fiber component of the carbs.

When my T1D daughter takes insulin to cover consumed carbs, we've found she needs to count all of the carbs or blood sugar stays too high. I don't know if it's just different for some reason from one person to the next, but bolusing for net carbs doesn't work out right for her.

I was not talking about the carb fiber connection in regards to the effect on insulin only but the high fiber carbs have proven to lower blood cholesterol levels, and are of great value to colon health, not to mention they make some people like me feel fuller longer.

yarwell

DeguelloTex wrote: »

yarwell wrote: »

DeguelloTex wrote: »

yarwell wrote: »

0.35 seems a reasonable start point, if a little arbitrary and perhaps reminiscent of low fat diets. Combined with another rule of thumb 10 kcal/lb it ends up at ~31.5 %cals from fat.

Are you saying 31% of calories from fat is reminiscent of low fat diets? That number is pretty much right in the middle of most every recommendation I've seen (25-35%). Or am I misunderstanding your point with that comparison?

25-35% is the low / reduced fat diet we're encouraged to eat.

How much fat were we encouraged to eat before we were encouraged to eat 25-35%?

that probably pre-dates nutritional guidelines, but 38% and higher were not unheard of. Before 1960 we hardly ate chicken, for example, but egg consumption was way higher than now.

yarwell

goldthistime wrote: »

Thanks for your response. Forgive my confusion, I'm not well versed in low carb, but you are saying that while the low fat diet allowed body fat to be burned beginning from day 1, the low carb diet reduced glycogen reserves before any body fat could be burned. Yes? Do you believe that after 8.5 days the weight loss and ratio of fat/lbm henceforth should be roughly equal between the two groups?

Probably. During the first few days of reducing carb intake the glycogen stores are being drawn on as well as increasing fat burn to replace the missing carbs. This can't go on for long, and by (say) day 10 either the fat burn will have to increase, the TDEE reduce or something along those lines.

In the low fat diet there is no carb reduction to compensate for but there was also a smaller drawdown of glycogen shown by an increase in CHO oxidation.

To begin with, if you look at Figure 3 H, the graph is meant to represent a prediction of what would happen after six months. As the carb level approaches zero (probably 5%?), the weight loss is predicted to be around 17kg for the low carb (RC) group, whereas the low fat (RF) group is shown to have a predicted weight loss of around 10 or 11kg. I thought we all agreed that after a certain point the two methods should converge and it becomes just about calories in/out again. The authors of this study really believe that there would be over a 5kg difference for two diets identical in CICO?

Yes, their model is showing a sensitivity to diet composition beyond energy value. This is known as the "expert mode" on their body weight simulator has an input for carbohydrate content. Some of that 5 kg will be reduced water associated with reduced glycogen.

If the answer is that the authors are extrapolating the results, no matter how inaccurate, why bother including grossly misleading charts?

Hall is a modeller, he sees the experiments as providing input to The Machine (tm) and uses models to predict longer term outcomes that are impractical to do in a metabolic ward.

The author states that DXA tests did NOT show a significant difference in fat loss between the two groups at the end of six days. I thought DXA was the gold standard in measuring fat loss. How sure are we that Hall's method of measuring fat loss is reliable?

"One female subject had changes in DXA % body fat data that were not physiological and were clear outliers, so these data were excluded from the analyses" Not physiological? I don't get it. Did she have liposuction while in that chamber? Why not tell us which group she was in?

The females did not have a statistically significant fat mass reduction by DEXA. The males did. The RC and RF diets gave a fat mass reduction in males that was not significantly different, although the calorie deficits were different. Fat mass loss per deficit was higher on reduced carbohydrate in males (contrary to the headline).

As well as the mystery woman two people received the wrong diet on one day, which in 6 days and 10 people might be quite significant. Stuff happens I guess. If you look at the supplementary tables the number being tested for certain things varies - 10 men did RC but only 8 did RF.

goldthistime

yarwell wrote: »

goldthistime wrote: »

Thanks for your response. Forgive my confusion, I'm not well versed in low carb, but you are saying that while the low fat diet allowed body fat to be burned beginning from day 1, the low carb diet reduced glycogen reserves before any body fat could be burned. Yes? Do you believe that after 8.5 days the weight loss and ratio of fat/lbm henceforth should be roughly equal between the two groups?

Probably. During the first few days of reducing carb intake the glycogen stores are being drawn on as well as increasing fat burn to replace the missing carbs. This can't go on for long, and by (say) day 10 either the fat burn will have to increase, the TDEE reduce or something along those lines.

In the low fat diet there is no carb reduction to compensate for but there was also a smaller drawdown of glycogen shown by an increase in CHO oxidation.

To begin with, if you look at Figure 3 H, the graph is meant to represent a prediction of what would happen after six months. As the carb level approaches zero (probably 5%?), the weight loss is predicted to be around 17kg for the low carb (RC) group, whereas the low fat (RF) group is shown to have a predicted weight loss of around 10 or 11kg. I thought we all agreed that after a certain point the two methods should converge and it becomes just about calories in/out again. The authors of this study really believe that there would be over a 5kg difference for two diets identical in CICO?

Yes, their model is showing a sensitivity to diet composition beyond energy value. This is known as the "expert mode" on their body weight simulator has an input for carbohydrate content. Some of that 5 kg will be reduced water associated with reduced glycogen.

If the answer is that the authors are extrapolating the results, no matter how inaccurate, why bother including grossly misleading charts?

Hall is a modeller, he sees the experiments as providing input to The Machine (tm) and uses models to predict longer term outcomes that are impractical to do in a metabolic ward.

The author states that DXA tests did NOT show a significant difference in fat loss between the two groups at the end of six days. I thought DXA was the gold standard in measuring fat loss. How sure are we that Hall's method of measuring fat loss is reliable?

"One female subject had changes in DXA % body fat data that were not physiological and were clear outliers, so these data were excluded from the analyses" Not physiological? I don't get it. Did she have liposuction while in that chamber? Why not tell us which group she was in?

The females did not have a statistically significant fat mass reduction by DEXA. The males did. The RC and RF diets gave a fat mass reduction in males that was not significantly different, although the calorie deficits were different. Fat mass loss per deficit was higher on reduced carbohydrate in males (contrary to the headline).

As well as the mystery woman two people received the wrong diet on one day, which in 6 days and 10 people might be quite significant. Stuff happens I guess. If you look at the supplementary tables the number being tested for certain things varies - 10 men did RC but only 8 did RF.

Thanks for taking the time to respond and for your other comments.

Although this was an interesting study, and the author proved what he had set out to prove (that body fat loss does not require reduction of insulinogenic carbohydrates), when I ask myself "what does this mean for me and my own diet?", I am tempted to conclude, "nothing".

Interested to hear if anyone out there now feels more compelled to move towards either a RF or a RC diet as a result of reading this study.

senecarr

I think Lyle McDonald had an interesting write up:
http://www.bodyrecomposition.com/research-review/reduced-fat-reduced-carbohydrate-diets.html/

goldthistime

senecarr wrote: »

I think Lyle McDonald had an interesting write up:
http://www.bodyrecomposition.com/research-review/reduced-fat-reduced-carbohydrate-diets.html/

Lol. Poor Gary.