As has been mentioned by other posters, this study demonstrated that carbohydrate restriction was as effective as extreme calorie restriction (as low as 1200kcal/d!) in causing weight loss. Carbohydrate restriction was better at improving just about every indicator of cardiovascular health that exists--triglyceride levels, HDL levels, blood pressure, etc.
The abstract for this study supports the assertion that carbohydrate restriction is an effective and healthy weight loss technique. It does support the assertion that starving yourself can also promote weight loss; I do not believe anyone here has disagreed with this hypothesis, however. (I would argue that few people will willingly remain on a 1200 kcal/day diet for the rest of their life, however.)
This study is dealing with low glycemic index diets, not low-carb diets. It is largely irrelevant to the discussion. (Note that frucose, a carbohydrate, has a very low glycemic index.)
This study deals with monounsaturated fatty acids (MUFA), not carbohydrate-restricted diets in general. I note also that the "high fat" diet in this study only included 35-45% of calories from fat, and about 45% of calories from carbohydrates. In other words, this study does not appear to contain any low-carbohydrate diets, and is again irrelevant to the discussion.
Leaving aside the rather scary warnings about liver damage, it appears that orlistat is used in conjunction with "an individualized low-calorie, low-fat diet".
This paper does not appear to have any relevance to a discussion of carbohydrate-restricted diets. (Except, perhaps, as an argument for the scary side effects of the alternatives.)
The "final nail" in the coffin of carbohydrate restriction, as you put it, appears to be a study comparing a fat-restricted/calorie-unrestricted diet with a calorie-restricted diet. Carbohydrate-restricted diets do not make an appearance.
End result: Four irrelevant studies, one which supports carbohydrate restriction as a superior alternative to calorie restriction for weight loss and cardiovascular health.
Paper #4 was a mistake and slipped in by accident. Sorry about that.
I think you're misreading and/or selectively quoting on most offer others, though.
Please remember, the argument is not "carb cutting has no beneficial effects". The argument is, "carb cutting has no long-term effects on weight loss."
"The abstract for this study supports the assertion that carbohydrate restriction is an effective and healthy weight loss technique. It does support the assertion that starving yourself can also promote weight loss; I do not believe anyone here has disagreed with this hypothesis, however. (I would argue that few people will willingly remain on a 1200 kcal/day diet for the rest of their life, however.)"
The abstract of the paper made it clear that attrition was high in both groups -- neither cohort could maintain their diets. Also, you're doing a fair amount of selective quoting. From the abstract, right before the part you quoted:
"There were no differences in weight, body composition, or bone mineral density between the groups at any time point."
In other words: neither group lost more weight than the other, at any time point. Which was the OP's point. Also, the following papers were trivial to find:
"Participants on a low-carbohydrate diet had more favorable overall outcomes at 1 year than did those on a conventional diet. Weight loss was similar between groups, but effects on atherogenic dyslipidemia and glycemic control were still more favorable with a low-carbohydrate diet after adjustment for differences in weight loss."
"After 6 months, individuals assigned to low-carbohydrate diets had lost more weight than individuals randomized to low-fat diets....This difference was no longer obvious after 12 months....Triglyceride and high-density lipoprotein cholesterol values changed more favorably in individuals assigned to low-carbohydrate diets....but total cholesterol and low-density lipoprotein cholesterol values changed more favorably in individuals assigned to low-fat diets"
"There is insufficient evidence to make recommendations for or against the use of low-carbohydrate diets, particularly among participants older than age 50 years, for use longer than 90 days, or for diets of 20 g/d or less of carbohydrates. Among the published studies, participant weight loss while using low-carbohydrate diets was principally associated with decreased caloric intake and increased diet duration but not with reduced carbohydrate content."
"Variability in dietary weight loss trials may be partially attributable to differences in hormonal response. Reducing glycemic load may be especially important to achieve weight loss among individuals with high insulin secretion. Regardless of insulin secretion, a low-glycemic load diet has beneficial effects on high-density lipoprotein cholesterol and triglyceride concentrations but not on low-density lipoprotein cholesterol concentration."
Confused? You should be. What a quick perusal of the evidence tells me is that a) despite what you may have read on the internet, the question is far from settled, and b) if there is any conclusion to be made, it's that low-carb diets may have some positive benefit on cholesterol and triglyceride levels, but don't seem to have any net benefit when it comes to weight control.
if there is any conclusion to be made, it's that low-carb diets may have some positive benefit on cholesterol and triglyceride levels, but don't seem to have any net benefit when it comes to weight control.
This observation is hugely important because one of the biggest myths about low-carb diets is that eating all that fat will be bad for your heart when in reality study after study shows that such diets outperform low-fat calorie-resricted diets on the most important lipid indicators - HDL, VLDL, and triglycerides.
The scare-tactic logic runs something along the lines of "Sure, you might lose weight but think about what you'll be doing to your heart."
When hard numbers show that eating unrestricted amounts of fat and protein lead to similar weight loss as a low-fat, calorie-restricted diet, the lipid results are swept under the rug.
This matches my personal experience. I had similar weight loss result on both types of diets, but my blood panels were dramatically better on a low-carb diet. I'd also add that I never felt hungry on a low-carb diet, while I was constantly hungry on the low-fat, calorie-restricted diet.
I find the main difficulty with low-carb diets is that they are boring. Our society does not cater to them. Ordering at restaurants and eating lunch with your workgroup when meals are brought in ase challenging. There's also a lot of social pressure around dessert (parties) and alcohol.
Unfortunately - at least for me - cheating on a low-carb diet is a major setback because it can set up a cycle of hunger that take at least a few days to get out of. Low-fat diets aren't the same, mostly because you are often convincing yourself to be hungry all the time anyway.
but my blood panels were dramatically better on a low-carb diet
My blood panels were exactly the opposite - bad when I ate cheese, meat, fried, oily stuff... good when I switched to a diet consisting mostly of rice, noodles, fruits and vegetables.
In other words: neither group lost more weight than the other, at any time point.
That's not the point, however--again, nobody argues that you can't cause people to lose weight by severely restricting their caloric intake. As study after study has shown, however, caloric restriction diets do not work in the long term. People just can't maintain semi-starvation diets indefinitely.
Furthermore, quoting the abstract: "After 3 months, participants in the low-carbohydrate diet group increased their carbohydrate intake (5 g/d per wk) until a stable and desired weight was achieved."
In other words, it is entirely expected that both groups had similar levels of weight loss, since the researchers explicitly took steps to ensure that this would be the case. The same presumably goes for the calorie-restricted group, since their calorie levels are given as 1200-1800 kcal/day--quite a wide range, indicating that the researchers adjusted caloric intake to achieve the desired levels of weight loss.
I would be interested to know what the relative attrition was between the two groups; the abstract does not include this information, and I don't feel like paying $15 for the full paper.
Your four new cites do not change the fact that of the OP's five cites, one argued against his position and four were irrelevant. Addressing yours, however...
Compares carbohydrate-restricted, calorie-unrestricted diet with fat-restricted, calorie-restricted diet. Finds that you lose as much weight eating as much as you want on a carbohydrate-restricted diet as you do starving yourself on a fat-restricted diet.
States that total cholesterol changed more favorably on a low-fat diet, which is strange, since total cholesterol is a lousy measure of anything. High HDL ("good cholesterol") levels are good, while high triglyceride levels are bad--what value can there possibly be in adding the two together?
States that LDL levels were "more favorable" in the low-fat contingent, but LDL is not a monolithic substance. Small, dense LDL is bad; large, less dense LDL is either good or not bad depending on who you talk to. High-fat diets are known to raise large LDL levels, so an increase in overall LDL in the carbohydrate-restricted group is entirely expected.
Meta-analysis. States that in published studies involving diets restricting carbohydrate intake to less than 90 g/day (~360 calories/day), there was no correlation between amount of carbohydrate intake and weight loss. In other words, their analysis indicates that once carbohydrate intake has been restricted to a certain level, further restriction may have no impact on weight loss.
They did not compare carbohydrate restricted diets with any other form of diet, and therefore cannot draw any conclusions regarding the relative effectiveness of carbohydrate restriction and any other diet.
Their analysis also reveals the lack of published research performed on carbohydrate-restricted diets over the past few decades. This fact is also unsurprising to anyone who has read GCBC.
The abstract does not indicate to what degree, if any, caloric restriction was used.
Compares a "low glycemic load" diet with a low fat diet; does not examine carbohydrate restriction. Note that the low glycemic load contingent was still receiving 40% of calories from carbohydrates.
This study also appears to have examined LDL without regard to LDL composition (small/dense vs. large/less-dense).
Confused?
No, not really.
My understanding is that a carbohydrate-restricted diet:
- Will promote weight loss without hunger.
- Will increase HDL levels (good cholesterol).
- Will decrease triglyceride levels (very, very bad stuff).
- Will increase LDL levels. LDL is "bad cholesterol", BUT...
- ...small LDL is correlated with CHD, and is not increased by a carbohydrate-restricted diet, AND...
- ...LDL in general is much less important than HDL and triglyceride levels as a risk factor for CHD.
Both your citations and those of the OP have either been irrelevant to these points or have supported them.
1. http://www.ncbi.nlm.nih.gov/pubmed/20679559
As has been mentioned by other posters, this study demonstrated that carbohydrate restriction was as effective as extreme calorie restriction (as low as 1200kcal/d!) in causing weight loss. Carbohydrate restriction was better at improving just about every indicator of cardiovascular health that exists--triglyceride levels, HDL levels, blood pressure, etc.
The abstract for this study supports the assertion that carbohydrate restriction is an effective and healthy weight loss technique. It does support the assertion that starving yourself can also promote weight loss; I do not believe anyone here has disagreed with this hypothesis, however. (I would argue that few people will willingly remain on a 1200 kcal/day diet for the rest of their life, however.)
2. http://www.ncbi.nlm.nih.gov/pubmed/20663066
This study is dealing with low glycemic index diets, not low-carb diets. It is largely irrelevant to the discussion. (Note that frucose, a carbohydrate, has a very low glycemic index.)
3. http://www.ncbi.nlm.nih.gov/pubmed/20670466
This study deals with monounsaturated fatty acids (MUFA), not carbohydrate-restricted diets in general. I note also that the "high fat" diet in this study only included 35-45% of calories from fat, and about 45% of calories from carbohydrates. In other words, this study does not appear to contain any low-carbohydrate diets, and is again irrelevant to the discussion.
4. http://www.ncbi.nlm.nih.gov/pubmed/20571327
This study appears to concern the use of the drug orlistat for weight maintenance following weight loss.
Orlistat: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0000175
Leaving aside the rather scary warnings about liver damage, it appears that orlistat is used in conjunction with "an individualized low-calorie, low-fat diet".
This paper does not appear to have any relevance to a discussion of carbohydrate-restricted diets. (Except, perhaps, as an argument for the scary side effects of the alternatives.)
5. The link for this is wrong. This appears to be the right one: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2125573/
The "final nail" in the coffin of carbohydrate restriction, as you put it, appears to be a study comparing a fat-restricted/calorie-unrestricted diet with a calorie-restricted diet. Carbohydrate-restricted diets do not make an appearance.
End result: Four irrelevant studies, one which supports carbohydrate restriction as a superior alternative to calorie restriction for weight loss and cardiovascular health.