Review finds low-carb eating benefits health markers

AlabasterVerve

Small snippet from Dr. Briffa's blog that sums up the meta-analysis. You can read the whole blog post here:
http://www.drbriffa.com/blog/

The review amassed data from 17 studies in the form what is called a ‘meta-analysis’ [1]. This sort of review study is not necessarily ideal, at least in part because it included approaches utilising different carbohydrate intakes over different lengths in sometimes quite different demographics of people. Also, another problem is that in studies of this nature people are usually ‘free living’, and this means that adherence to the ‘diet’ is not assured and tends to drop off over time too.

Nevertheless, the broad results from this review make interesting reading in that, overall, low carbohydrate eating was found, on average to bring statistically significant benefits in several measures including:

Body weight (average loss of 7 kg)
Abdominal circumference (average reduction of 5.74 cm = 2.26 inches)
Systolic blood pressure (average reduction of 4.81 mmHg)
Diastolic blood pressure (average reduction of 3.10 mmHg)
HbA1c – also known as glycosylated haemoglobin and a measure of blood sugar control over the preceding 3 months or so (average reduction 0.21 per cent)
Reduction in blood insulin levels
C-reactive protein reduction (an inflammatory marker – inflammation being something that has the capacity to drive disease process)
Increase in levels of supposedly ‘healthy’ HDL cholesterol

No overall effect was seen on levels of supposedly ‘unhealthy’ LDL cholesterol. Though, we know from research that low carbohydrate diets tend to lead to lead to increases in the size of LDL particles and reduce the number of ‘small, dense’ LDL – changes that are believed to be desirable in terms of cardiovascular disease risk reduction [2].

taylor5877

AlabasterVerve

lol What? I just thought low-carbers could use a little pick me up after all the misinformation and insults from the 101 Reasons thread.

taylor5877

Nah, the defenders of the carbs will be out in force on this one in no time.

AlabasterVerve

SECOND STUDY

Here's another from Dr. Eades blog. Much more interesting than the fist study I think because it's something new. Small snippet, you can read the rest here:

http://www.proteinpower.com/drmike/inflammation/can-your-food-make-you-fit/

What did study #1 show?

Interestingly, despite the 40% caloric overfeeding, no significant changes in body weight occurred in either diet. And there were no changes in insulin sensitivity, glucose, lipids or other parameters measured. What was truly amazing, however, was what happened to AMPK activation. Low-fat/high-carb overfeeding did not produce any effect of AMPK activity as compared to baseline. But low-carb/high-fat overfeeding produced a significantly increased activation of AMPK.

In referring to these two studies, the researchers noted:

We observed that caloric restriction with [a low-fat/high-carb] diet did not alter the AMPK [activation], suggesting that increased dietary carbohydrate content even in the face of caloric restriction prevented activation of AMPK… in skeletal muscle of obese individuals. In contrast, overfeeding with [a low-carb/high-fat] diet increased the activity of this pathway [AMPK] indicating that low carbohydrate content may be sufficient for its activation.

And in summary, they commented:

Our data indicate that a relative deficiency in carbohydrate intake or, albeit less likely, a relative excess of fat intake even in the absence of caloric deprivation is sufficient to activate this network and increase fat oxidation.

These studies may provide an answer as to why most weight-loss studies comparing low-fat/high-carb diets to low-carb/high-fat diets almost always find the low-carb diet to bring about the greatest loss.

DanaDark

Funny how most of these studies always ignore protein.

Also, the idea that an apple, a banana, broccoli, celery etc is worse for you than a bucket of lard is laughable at best.

Healthy carbs is where it's at, combined with a decent amount of protein.

Typically, a low carb diet encourages greater protein intake (this is the key improvement, not necessarily the carb reduction, but the protein increase). It also encourages significantly fewer "bad" carbs such as heavily processed foods and many snack items.

As well, any diet studies that use "free living" diets are about as useful as tits on a bull.

A diet that promotes less snack foods, less processed foods, and more protein will generally show decent results. This diet can still be achieved with moderate to high carbs.

AlabasterVerve

What did you think of the second study, Dana?

Spartan_Maker

lol What? I just thought low-carbers could use a little pick me up after all the misinformation and insults from the 101 Reasons thread.

Once the sugar-burners elevate their collective blood sugars and spike their insulin through the roof, they'll be maniacally trolling this thread. Just give it time.

DanaDark

What did you think of the second study, Dana?

I don't see a second study but rather a link to a blog. Which also notes "Free Living" in the quote.

All the reductions mentioned show absolutely no CAUSATION via low carb.All those results have been also achieved via higher carb diets provided the carbs are healthy. By going based on percentages rather than set amounts, changes in ONE variable results in automatic changes in ANOTHER variable (TERRIBLE science, no study could draw conclusions without controlling the variables).

The standard diet recommended by the FDA and Department of Health is quite awesome really. It's ranges for suggested intake adequately cover most macro-focused diets, including many standard low carb diets as well as high carb ones.

I know many will swear by pretty much any diet in the world, but again, most diet plans fall within the range of the recommended.

I have not seen very many studies (have seen some though) that explain their methodology, and explicitly controlled their variables.

Spanaval

The link to the abstract of the meta analysis is here:

http://onlinelibrary.wiley.com/doi/10.1111/j.1467-789X.2012.01021.x/abstract;jsessionid=7396D07C42DB2B84642D35158B132AF9.d04t04

They don't, unfortunately, provide the full article for free. The questions I would have are as follows:

1. Are the low carbers eating at maintenance? Below? Above? (I'd guess below)
2. If it is eating at or above maintenance, did they meet the caloric requirements by increasing protein or increasing fats or both?
3. If they are eating below maintenance, is there any study out there that shows that weight loss (by any reasonable means) wouldn't achieve the same results? Or that the benefits to health markers as shown on the low carb diet is statistically significant in terms of being better than a different type of isocaloric diet (high carb or high fat, while holding protein constant, for instance).

AlabasterVerve

The first study was just a meta-analysis of existing studies on low carbohydrate diets -- with all the usual crap nutritional science that implies -- but what about the second study I posted? I think that's exciting stuff since it seems to offer a possible explanation for why low carb diets a lot of the times show greater weight loss.

If I'm understanding it right AMPK does this:

AMPK is one of the primary signaling proteins that monitors the ATP levels in the cells and signals for more energy when levels drop. When AMPK is activated indicating our cellular energy tanks are depleted, all kinds of good things happen. Here is a short list of metabolic efforts all kicked into action by activated AMPK and why they’re important. (adapted from ref #6)

Increases glucose uptake: We want to get glucose out of the blood and into the cells to burn.
Increases glycolysis: We need to break down glycogen (stored sugar) to get the glucose to burn.
Increases fatty acid oxidation: An obvious one. We want to start burning fat to replenish the depleted energy stores.
Increases mitochondrial biogenesis: we want to make more mitochondria to burn fat and generate as much ATP as possible.
Inhibits gluconeogenesis: We don’t want to spend energy making more sugar – we want to burn it.
Inhibits glycogen synthesis: Same thing – we don’t want to store sugar, we want to burn it.
Inhibits fatty acid and cholesterol synthesis: We don’t want to spend energy making fat and cholesterol.
Inhibits insulin secretion: We want insulin to be low, so that we can move stored fat and sugar to where it needs to be burned.

But a high carbohydrate diet prevents AMPK:

As the study authors put it, this change as a function of carb restriction

suggest[ed] that high carbohydrate intake prevents activation of AMPK… in skeletal muscle that otherwise would have been induced by caloric deprivation.

Much more research needs to be done as Dr. Eades points out but for me, like I said, it's exciting stuff. I know a low carb diet works for me in a way just reducing calories never has so it's pretty cool to see a possible explanation for why it works. I'm kinda dorky like that though -- this stuff fascinates me.

SECOND STUDY

Here's another from Dr. Eades blog. Much more interesting than the fist study I think because it's something new. Small snippet, you can read the rest here:

http://www.proteinpower.com/drmike/inflammation/can-your-food-make-you-fit/

What did study #1 show?

Interestingly, despite the 40% caloric overfeeding, no significant changes in body weight occurred in either diet. And there were no changes in insulin sensitivity, glucose, lipids or other parameters measured. What was truly amazing, however, was what happened to AMPK activation. Low-fat/high-carb overfeeding did not produce any effect of AMPK activity as compared to baseline. But low-carb/high-fat overfeeding produced a significantly increased activation of AMPK.

In referring to these two studies, the researchers noted:

We observed that caloric restriction with [a low-fat/high-carb] diet did not alter the AMPK [activation], suggesting that increased dietary carbohydrate content even in the face of caloric restriction prevented activation of AMPK… in skeletal muscle of obese individuals. In contrast, overfeeding with [a low-carb/high-fat] diet increased the activity of this pathway [AMPK] indicating that low carbohydrate content may be sufficient for its activation.

And in summary, they commented:

Our data indicate that a relative deficiency in carbohydrate intake or, albeit less likely, a relative excess of fat intake even in the absence of caloric deprivation is sufficient to activate this network and increase fat oxidation.

These studies may provide an answer as to why most weight-loss studies comparing low-fat/high-carb diets to low-carb/high-fat diets almost always find the low-carb diet to bring about the greatest loss.

Acg67

The first study was just a meta-analysis of existing studies on low carbohydrate diets -- with all the usual crap nutritional science that implies -- but what about the second study I posted? I think that's exciting stuff since it seems to offer a possible explanation for why low carb diets a lot of the times show greater weight loss.

If I'm understanding it right AMPK does this:

AMPK is one of the primary signaling proteins that monitors the ATP levels in the cells and signals for more energy when levels drop. When AMPK is activated indicating our cellular energy tanks are depleted, all kinds of good things happen. Here is a short list of metabolic efforts all kicked into action by activated AMPK and why they’re important. (adapted from ref #6)

Increases glucose uptake: We want to get glucose out of the blood and into the cells to burn.
Increases glycolysis: We need to break down glycogen (stored sugar) to get the glucose to burn.
Increases fatty acid oxidation: An obvious one. We want to start burning fat to replenish the depleted energy stores.
Increases mitochondrial biogenesis: we want to make more mitochondria to burn fat and generate as much ATP as possible.
Inhibits gluconeogenesis: We don’t want to spend energy making more sugar – we want to burn it.
Inhibits glycogen synthesis: Same thing – we don’t want to store sugar, we want to burn it.
Inhibits fatty acid and cholesterol synthesis: We don’t want to spend energy making fat and cholesterol.
Inhibits insulin secretion: We want insulin to be low, so that we can move stored fat and sugar to where it needs to be burned.

But a high carbohydrate diet prevents AMPK:

As the study authors put it, this change as a function of carb restriction

suggest[ed] that high carbohydrate intake prevents activation of AMPK… in skeletal muscle that otherwise would have been induced by caloric deprivation.

Much more research needs to be done as Dr. Eades points out but for me, like I said, it's exciting stuff. I know a low carb diet works for me in a way just reducing calories never has so it's pretty cool to see a possible explanation for why it works. I'm kinda dorky like that though -- this stuff fascinates me.

SECOND STUDY

Here's another from Dr. Eades blog. Much more interesting than the fist study I think because it's something new. Small snippet, you can read the rest here:

http://www.proteinpower.com/drmike/inflammation/can-your-food-make-you-fit/

What did study #1 show?

Interestingly, despite the 40% caloric overfeeding, no significant changes in body weight occurred in either diet. And there were no changes in insulin sensitivity, glucose, lipids or other parameters measured. What was truly amazing, however, was what happened to AMPK activation. Low-fat/high-carb overfeeding did not produce any effect of AMPK activity as compared to baseline. But low-carb/high-fat overfeeding produced a significantly increased activation of AMPK.

In referring to these two studies, the researchers noted:

We observed that caloric restriction with [a low-fat/high-carb] diet did not alter the AMPK [activation], suggesting that increased dietary carbohydrate content even in the face of caloric restriction prevented activation of AMPK… in skeletal muscle of obese individuals. In contrast, overfeeding with [a low-carb/high-fat] diet increased the activity of this pathway [AMPK] indicating that low carbohydrate content may be sufficient for its activation.

And in summary, they commented:

Our data indicate that a relative deficiency in carbohydrate intake or, albeit less likely, a relative excess of fat intake even in the absence of caloric deprivation is sufficient to activate this network and increase fat oxidation.

These studies may provide an answer as to why most weight-loss studies comparing low-fat/high-carb diets to low-carb/high-fat diets almost always find the low-carb diet to bring about the greatest loss.

Unless of course you hold cals and protein constant, and you focus on fat loss not weight loss

AlabasterVerve

Unless of course you hold cals and protein constant, and you focus on fat loss not weight loss

Acg67, what does that have to do with AMPK? If a high carb diet does inhibit AMPK do you think it's possible that that would effect fat loss?

ETA:
James Steele II also posted this in the comments section which I thought was equally interesting.

Fantastic stuff, thanks for sharing this as it had fell under my radar also.

Tim Noakes would probably be interested to see this as to my understanding he is doing work with athletes on low carb dieting and endurance performance. It would be interesting to see if this short term activation was sufficient to produce an improvement in acute performance measures, or, assuming the AMPK activation holds up over more chronic periods, whether this might be an important mechanism for how low carb diets appear to benefit athletes, particularly endurance athletes.

Fasted training influences greater AMPK activation also and has shown greater adaptations in VO2max after a training intervention compared with a high carb pre-training intake, so it seems reasonable to speculate that low carb dieting and training might do the same.

On another note, and as I know you are a fan of SlowBurn/HIT style training, you might be interested in a piece I published earlier this year in which I reviewed the mechanisms of AMPK activation in producing cardiovascular fitness improvement from high intensity resistance training.

http://faculty.css.edu/tboone2/asep/JEPonlineJUNE2012_Steele.pdf

Acg67

Unless of course you hold cals and protein constant, and you focus on fat loss not weight loss

Acg67, what does that have to do with AMPK? If a high carb diet does inhibit AMPK do you think it's possible that that would effect fat loss?

Do a little more research on AMPk and lipolysis

SalishSea

Bump. Love low carb!

AlabasterVerve

Unless of course you hold cals and protein constant, and you focus on fat loss not weight loss

Acg67, what does that have to do with AMPK? If a high carb diet does inhibit AMPK do you think it's possible that that would effect fat loss?

Do a little more research on AMPk and lipolysis

Huh? How would researching AMPK and lipolysis tell me what you think about this research and its potential implications?

DanaDark

1. A body low in cabrs will naturally want to store the ones it does get simply because it depleted the stores already. This will not effect fat.

2. A low calorie diet (with enough protein) will result in the need for utilization of fat stores.

3. Every study has not kept their constants actually constant and have checked multiple variables AT THE SAME TIME (absolutely bad science).

The main reason low carb works for some people for weight loss is the increased protein.

The reason why low carbers tend to use more energy per day than those of the same weight are two fold. The first being the low carbers have more protein where as the other groups typically do not have enough (most studies place them at 10 to 20% and low-carbers at 30%). And secondly, the non-low-carbers are actually smaller in reality (lean body mass). The low carbers have an artificially lower weight due to significantly less water weight. Larger lean body mass means larger caloric expenditure.

Lowering one thing AND raising another, then only saying "lower this" is ridiculous in its very nature.

And... "Free-living".... really...

AlabasterVerve

1. A body low in cabrs will naturally want to store the ones it does get simply because it depleted the stores already. This will not effect fat.

2. A low calorie diet (with enough protein) will result in the need for utilization of fat stores.

3. Every study has not kept their constants actually constant and have checked multiple variables AT THE SAME TIME (absolutely bad science).

The main reason low carb works for some people for weight loss is the increased protein.

The reason why low carbers tend to use more energy per day than those of the same weight are two fold. The first being the low carbers have more protein where as the other groups typically do not have enough (most studies place them at 10 to 20% and low-carbers at 30%). And secondly, the non-low-carbers are actually smaller in reality (lean body mass). The low carbers have an artificially lower weight due to significantly less water weight. Larger lean body mass means larger caloric expenditure.

Lowering one thing AND raising another, then only saying "lower this" is ridiculous in its very nature.

And... "Free-living".... really...

Dana, if the research can't say that lower carbs is responsible for the increased weight loss you can't use the same research to claim the results are from an increase in protein. I'd also like to point out that not all low carb diets increase protein, most that I know of are low carb, high fat, and adequate protein.

DanaDark

Dana, if the research can't say that lower carbs is responsible for the increased weight loss you can't use the same research to claim the results are from an increase in protein. I'd also like to point out that not all low carb diets increase protein, most that I know of are low carb, high fat, and adequate protein.

I don't use the same research in determining that higher protein helps, there has been much research on that specifically.

I know you may think I am saying "Its so bad and you'll DIE if you eat that way for even a day and you'll NEVER lose weight!", but that is totally not what I am saying at all.

A balanced diet (has proper carbs, fats, and enough protein) that consists of healthy foods is simply unbeatable.

And, I have not noticed any low carb specific diets that say lower carbs and raise fats and not protein. But from the studies I have read, the low carb dieters had increased protein EVERY time. (200% to 300% more than the "control" group or the opposed diet plan).

If low carb has been working for you, and your health is just fine, then continue. The most important factor is being able to live YOUR ENTIRE life like that. That is where most plans fall apart, as many have issues sticking to any type of diet that restricts entire food categories. This isn't just a low-carb thing, but even low-fat diets are hard to stick to.

I point out flaws in certain studies, and suddenly I am considered as some sort of Demon Hunter going hog wild in the depths of the netherworld lol.

I think ALL diets can work, problem is finding ones that you can stick to. The HARDEST is the plain old balanced diet because it seems so counter intuitive. Many people want that strict rule book.

So please, don't think I am saying you're doomed to failure simply because I see flaws in some studies that support your diet plan. I see flaws in MANY studies.

yarwell

A balanced diet (has proper carbs, fats, and enough protein) that consists of healthy foods is simply unbeatable.

Can you a) define this and b) provide supporting evidence to your usual high standards ?

DanaDark

Can you a) define this and b) provide supporting evidence to your usual high standards ?

http://www.health.gov/dietaryguidelines/dga2010/DietaryGuidelines2010.pdf

Worth noting, as I have before, that playing with the suggested intakes (Which is a RANGE), you can achieve a semi-low-carb diet (One that I'd support in this range).

This is a Document published by the Department of Agriculture and Department of Health and Human Services written by 15 highly qualified individuals (Masters and Doctorates in the related field) and reviewed by another 11 official in the field as well.

I really enjoy this sort of stuff more so than some guy's blog or random internet forum posts by mysterious men.