Dose-Response for Carbs
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wabmester
Posts: 2,748 Member
We talk a lot about different carb levels around here, but I've never been able to find a study that looked at the effects of varying those levels. This is known as the dose-response curve -- what response do you get as you vary the dose of carb intake?
Turns out Volek did a study last year:
Effects of Step-Wise Increases in Dietary Carbohydrate on Circulating Saturated Fatty Acids and Palmitoleic Acid in Adults with Metabolic Syndrome
He was mostly interested in the effects of increasing carbs and decreasing saturated fat on the SFA content of the blood, but the other results are interesting too.
The carb intake varied from 47g-346g/d. Calories were kept constant, and the diet was hypocaloric, so the subjects continued losing weight regardless of carb intake. (This could be seen as a good reason to count calories.)
Ketones increased at all carb levels between 47g-179g/d. More ketones at lower carbs, as you'd expect.
Body fat dropped at all levels.
Systolic blood pressure dropped at all levels, but dropped the most as carbs went up to 346g/d (and body fat was at lowest level).
Insulin sensitivity improved at all levels, but was highest at the lowest carb level of 47g/d.
Really, the only metric that got worse as carbs increased were the triglycerides and diastolic BP.
It validates Volek's hypothesis about TG and SFA in the blood, but it also validates CICO and the benefits of weight loss regardless of how you get there. Cool study!
Turns out Volek did a study last year:
Effects of Step-Wise Increases in Dietary Carbohydrate on Circulating Saturated Fatty Acids and Palmitoleic Acid in Adults with Metabolic Syndrome
He was mostly interested in the effects of increasing carbs and decreasing saturated fat on the SFA content of the blood, but the other results are interesting too.
The carb intake varied from 47g-346g/d. Calories were kept constant, and the diet was hypocaloric, so the subjects continued losing weight regardless of carb intake. (This could be seen as a good reason to count calories.)
Ketones increased at all carb levels between 47g-179g/d. More ketones at lower carbs, as you'd expect.
Body fat dropped at all levels.
Systolic blood pressure dropped at all levels, but dropped the most as carbs went up to 346g/d (and body fat was at lowest level).
Insulin sensitivity improved at all levels, but was highest at the lowest carb level of 47g/d.
Really, the only metric that got worse as carbs increased were the triglycerides and diastolic BP.
It validates Volek's hypothesis about TG and SFA in the blood, but it also validates CICO and the benefits of weight loss regardless of how you get there. Cool study!
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Very interesting!
I have always done whatever nutritional approach at a CICO point of reference.
Protein is a desired fuel for me, not sugar. I would rather have a steak than two cans of coke.0 -
This is very interesting! If and when this sort of thing gets replicated and then makes it's way to the mainstream it's going to turn the world of nutrition upside down.0
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Yeah, a lot of people (including me) assumed that excess carbs were only harmful in the context of excess calories. The most interesting result of this study is that excess carbs still have an impact on blood triglycerides even when calories are restricted.
The proposed mechanism is de novo lipogenesis. The proposed biomarker is palmitoleic acid. There have been other studies to support these ideas, but they don't appear to be widely accepted yet.
Maybe not that interesting to people looking at ketosis for weight loss, but potentially very interesting for those who consider it for the health benefits.0 -
I looked at it briefly, so was each participant eating the 6 different phases ~ each phase for 3 weeks? Doesn't seem like a lot of time for your body to adjust. But it looks like it did.
It would also be interesting if they had done Keto (47g @ day is borderline) AND let the person get Adapted.
I don't see in the study and don't know how they would measure it, would be if the higher carb levels created more hunger levels? That is low-carb's claim-to-fame. Lower hunger levels are what make the difference between losing the weight and keeping it OFF. I have lost weight in a major weigh about 3 times in my life pre-keto. Every single time, I lost the weight, by sheer will power ALONE, when I got to my goal weight, I said to myself, "Never again" because the hunger levels were so intense. Subsequently I would maintain for a week to a couple months then start to gain it all back and then some.
It would take me 10 years before I would try another low-fat diet, same results (definition of insanity anyone?)
But, I will say that the Keto diet IS different, my hunger levels are manageable (except when we have free pecans at work ~ my kryptonite LOL! actually I can control myself, but they taste so good, its hard.)
Dan the Man from Michigan
Should You Use a Kitchen Scale to Weigh Your Food?
Should a Person Have a Food Diary for the Keto Diet?
DittoDan's Blood Work Results 6-18-2015
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A couple flaws, I think, in the study:
1. The subjects were losing weight the whole time. The weight loss itself could be a component of the blood markers (this is kind of a known thing). I think the study would have been stronger if the weight goal was maintenance, not loss. This is especially evident with the systolic blood pressure change -- was it the increasing carbs or the decreasing weight that was the real reason for the improvement?
2. There were no wash-out periods between each phase. Given the delayed response nature of dietary adjustments, this could be significant.
3. Each test period seems too short. Dan talked about this and I'm inclined to agree. I think this study could have been stronger had they doubled the time for each phase. One thing to note, though, was that the 47g phase actually kind of had a 6-week run from the subjects' perspective, given the run-in phase was 3 weeks on <50g carbs.
It's a great start, though, overall. I hope he tightens it up and does a follow-up (or someone does).0 -
It would also be interesting if they had done Keto (47g @ day is borderline) AND let the person get Adapted.
They did keto, and they had time to adapt. 6 weeks at below 50g. I assume everybody recognizes the author -- he coined the terms "nutritional ketosis" and "keto-adapted," so he knows about ketogenic diets.
The interesting thing to me is that this study showed the subjects were still making ketones even at 179g carbs. All low carb diets are ketogenic as long as the carbs are low enough.I don't see in the study and don't know how they would measure it, would be if the higher carb levels created more hunger levels?
Not this study, but others have measured a hunger hormone (ghrelin). Ketosis is proven to reduce ghrelin.Dragonwolf wrote:The subjects were losing weight the whole time. The weight loss itself could be a component of the blood markers (this is kind of a known thing). I think the study would have been stronger if the weight goal was maintenance, not loss.
Well, the study was specifically designed to show that high-carb diets raised TG and SFA levels even during weight loss (due to a hypocaloric diet), so that would have been a completely different study.
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Yeah, a lot of people (including me) assumed that excess carbs were only harmful in the context of excess calories. The most interesting result of this study is that excess carbs still have an impact on blood triglycerides even when calories are restricted.
The proposed mechanism is de novo lipogenesis. The proposed biomarker is palmitoleic acid. There have been other studies to support these ideas, but they don't appear to be widely accepted yet.
Maybe not that interesting to people looking at ketosis for weight loss, but potentially very interesting for those who consider it for the health benefits.
Yeah, I sent this on to a friend. We were chatting last summer and wondering if refined carbs would ultimately be the key to all of this stuff...I'm still thinking we will.0 -
Dragonwolf wrote: »A couple flaws, I think, in the study:
1. The subjects were losing weight the whole time. The weight loss itself could be a component of the blood markers (this is kind of a known thing). I think the study would have been stronger if the weight goal was maintenance, not loss. This is especially evident with the systolic blood pressure change -- was it the increasing carbs or the decreasing weight that was the real reason for the improvement?
2. There were no wash-out periods between each phase. Given the delayed response nature of dietary adjustments, this could be significant.
3. Each test period seems too short. Dan talked about this and I'm inclined to agree. I think this study could have been stronger had they doubled the time for each phase. One thing to note, though, was that the 47g phase actually kind of had a 6-week run from the subjects' perspective, given the run-in phase was 3 weeks on <50g carbs.
It's a great start, though, overall. I hope he tightens it up and does a follow-up (or someone does).
So in theory if they reversed the order and did the study again.
Then doubled the time for each phase.0 -
Dragonwolf wrote:The subjects were losing weight the whole time. The weight loss itself could be a component of the blood markers (this is kind of a known thing). I think the study would have been stronger if the weight goal was maintenance, not loss.
Well, the study was specifically designed to show that high-carb diets raised TG and SFA levels even during weight loss (due to a hypocaloric diet), so that would have been a completely different study.
Fair enough. To that end, it was a good study, then, and I stand corrected on that one. The other conclusions/observations would still be best served being strengthened by follow-ups that removed the intentional weight loss component. I hope he does such follow up studies in the near future. 0 -
Sabine_Stroehm wrote: »Yeah, I sent this on to a friend. We were chatting last summer and wondering if refined carbs would ultimately be the key to all of this stuff...I'm still thinking we will.
I was just cruising the main forum. The standard response there seems to be "Unless you have diabetes, insulin resistance, metabolic syndrome, hypoglycemia, hyperinsulinemia, don't worry about sugar intake." It'd be nice if they modified that to "Unless you don't want diabetes, insulin resistance, metabolic syndrome, hypoglycemia, hyperinsulinemia, don't worry about sugar intake."Sabine_Stroehm wrote: »So in theory if they reversed the order and did the study again.
They actually did reverse the order for 5 of the 16 subjects, and they found no difference.
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I was just cruising the main forum. The standard response there seems to be "Unless you have diabetes, insulin resistance, metabolic syndrome, hypoglycemia, hyperinsulinemia, don't worry about sugar intake." It'd be nice if they modified that to "Unless you don't want diabetes, insulin resistance, metabolic syndrome, hypoglycemia, hyperinsulinemia, don't worry about sugar intake."
How TRUE!
Dan the Man from Michigan
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