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Thursday, May 17, 2012

LC v. LF Diet Comparison Study Shows Calories Determine Weight Loss


From the paper:
In the low-fat group, the mean age was 62.7±11 years, there were 13 men and 18 women and the mean duration of known diabetes was 8.8±6.2 years.Corresponding figures for the low-carbohydrate group were 61.2±9.5 years, 14 men and 16 women and a duration of known diabetes of 9.8±5.5 years. Age, sex distribution and known duration of diabetes did not differ between the groups (all p>0.5).
This was a two year study with assessments at 6, 12 and 24 months along with an additional assessment of intake at 3 months.  These time frames match up with Shai.   Unlike Shai, the dietary prescriptions for both LF and LC were calorie restricted -- 1600 cal/day women, 1800 cal/day men and for LC there was no induction/phasing in more carbs.  Average intake was assessed with 3 days of journaling including 1 weekend day.  The oral medication usage at baseline was quite a mixed bag but similar between groups.  For LF/LC the numbers were:  diet only - 2/2,  oral hypoglycemics - 13/15, oral hypo + insulin - 11/10.  The breakdown of statin use by number of patients wasn't reported, though average dosage was provided in the summary table.  

For most of the participants, the intervention was comprised of some initial dietary instruction and monthly group meetings.  Dietary instruction was provided at baseline, 2, 6, and 12 months by different physicians.  A dietitian provided the first week's menu, recipes, and was available to ask questions at group meetings but individual counseling was not provided for all.  For some reason, during the first year, the dietitian had individual consultations with 4 LC'ers and 3 LF'ers.  Retention was good as only 3LF/4LC were lost for failure to attend meetings.    However at 24 months, the dietary record submission was quite different between groups with only 4 LF'ers (out of 28 completers) not submitting records while 10 LC'ers (out of 26 completers!) did not submit.
So, here are the results.  (Intent to treat analysis includes all 61 participants at all time points although 3LF and 4LC did not complete the study).  At 6 months, the weight loss was the same:   LFD = 4.0 ± 4.1 kg, LC = 4.3 ± 3.6 kg.  The plot for all time points is shown at right.  The weight change was statistically similar at all time points.  ● = LC, ■ = LC


Here's the major significant finding some low carb advocates are crowing over. This is change in HbA1c from baseline. First, I don't think this is anything to write home about for low carb. Yes, at 6 months it had dropped significantly, but it was back to baseline at two years. But let's look at that data with some absolute numbers shall we? I cleaned up the portion of Table 1 related to HbA1c (removed p-value columns). If you look at the full text, there is only one p-value for differences at any time point that even comes close to a level of significance. That is the HbA1c in mmol/mol (which is what is plotted in the figure) for the LC diet at 6 months compared to baseline. And if one looks at the HbA1c more commonly measured, we're talking no real impact whatsoever! It seems to me that highlighting this in the manner in which it was done shows a bit of a bias here.

Remember, these are T2's that are mostly receiving diabetic meds. I don't see the point in taking the time to include the entire med breakdown here, I'll put 0, 6, 12, 24 numbers in ( ). If you check, the only meds that appear to differ between the diets are insulin (LF: 39,38,38,36 ; LC: 42,30,33,35) and glibenclamide (LF: 0.4,0.3,0.3,0.3 ; LC: 1.1,0.5,0.5,0.1). I'm thinking that the mix of what oral meds were taken etc. is why the glibenclamide is not mentioned, probably one person taken off meds? In any case, only the difference in insulin dose is mentioned by the authors.  This is important, IMO, if one views insulin as a drug rather than a supplement for an underactive pancreas much like thyroid meds are viewed.  It should be no surprise that insulin needs would be reduced slightly according to the glycemic load of one's diet.  How much insulin any diabetic needs is not a measure of health or management of disease unless you're at war with a hormone critical to sustain life.

The only other thing mentioned in the study discussion was HDL.  Here are HDL levels for 0, 6, 12 and 24 months in mmol/l ± SD:
LF: 1.09 ± 0.29, 1.10 ± 0.30, 1.17 ± 0.24, 1.20 ± 0.32 (42 → 46 mg/dL, 4 pt increase)
LC: 1.13 ± 0.33, 1.25 ± 0.47, 1.24 ± 0.38, 1.36 ± 0.44 (44 → 53 mg/dL , 9 pt increase)
Eh ... Given the variability of cholesterol determinations, while the LC group made it over 50, this is hardly a compelling case for LC over LF. When you look at the "compliant completers" (we are not given numbers here per group, but we do know that at 24 months this at most included 24 LF'ers and 16 LC'ers).

So ... what can we learn from this study?   First let's take a look at the diets themselves.  From the paper:
%F / %C / %P:       Low Fat:  30/ 55-60 /10-15            Low Carb: 50/ 20 /30
I find it odd that the macro percents were fixed for LC but varied for LF.  And at first glance that protein differential popped out at me!  I mean, the LC group would have consumed 2-3X the protein of the LF group and I couldn't help but think of the LoBAG studies and the insulin sensitizing and HbA1c improving qualities of protein.  (See here).   I also found this study being touted by a low carb advocate in the context of high fat diet wins.  By LCHF standards, this is not a high fat diet.  A piddly 50% fat?  Heck, that's almost SAD-like.  Usually studies like this are criticized for not using an appropriate low carb diet, but when the headlines sound favorable, what's a little deviation amongst friends?   

In any case, we are provided intake data for compliant completers. That is those who attended meetings, and whose submitted 3-day food logs (for which they were provided scales/measuring devices) at the 24 month point demonstrated adherence to calorie targets (1600F/1800M).  The weight losses are even more dismal!  Only 3.1 kg on average for the LF, 3.6 kg for the LC group.  The HbA1c and HDL is shown at right.  Not much different than the whole group.  For the HbA1c thing, the values are a total wash between groups from the 1 to 2 year mark and if you want to to hang your hat on HDL, have at it!

So now, I ask, what can we learn -- if anything -- from this study?  Well, for starters, we've got the usual result that over the long term it's all a wash.  But this one is a little different to me.  Because at least the target caloric intake was counseled to be the same.  Voila!  And there went the usual differences in short term weight loss out the window!  It wasn't because the LC'ers didn't eat enough fat and calories, although to this day if you go on a low carb forum and ask for help as to why you've been LC for two years and only lost like 10 lbs, you'll probably be asked if you're eating enough should you dare mention counting/tracking calories!  

No ... this study shows calories count, macros, not so much.

Sadly, we don't get the intake breakdown for just the compliant completers, but this is the breakdown for those who submitted 3-day dietary records at each time point.  I note that even fewer reported at 12 months, and I remind you that at 24 months, only 4 LF'ers didn't report while 10 LC'ers failed to report.

I find the progressions for both groups odd.  So they were more compliant 3-6 months, slacked off a bit at 12 months then clamped down big time at two years?   Not really buying that!  So they the LF and LC groups were consuming ~1450 and ~1250 cal/day respectively at the two year mark despite counsel to consume an average of 1700 cal/day?  

The LF group never exceeds the 50% mark for carbs, and protein is roughly 20% despite prescribed at 10-15%.  Meanwhile, the LC group never makes it to 25% protein despite the 30% target, and they also miss their carb target by quite a bit consuming ~25% carb at 6 mo and 1 yr, and 30% at 2 years!  And fat?  well, the LC group were higher fat consumers at baseline!  And look at the low fatties, they barely altered fat consumption, though I suppose the LC group can write home about eating "a lot" more fat for the first year.  The 2 year fat consumption is only a smidge more than baseline.   Let's put some grams to this, shall we?  At 6 months:     LF:  1553 cal,  190g carb,  50g fat,  82g protein    and   LC:  1384 cal,   87g carb,   75g fat,  83g protein.  So, actually absolute protein was similar and this just goes to show that if anything, metabolic "tie" weight-loss-wise goes to LF as they had same weight loss consuming over 150 cal/day more cals.  And at 2 years?  Well:  LF:  1459 cal,  171g carb, 50g fat, 73g protein    and    LC:  1251 cal, 97g carb, 61g fat, 75g protein.  It's no wonder such minor differences were observed.

Do we learn anything from this study?  Something about reality I suppose.  That if you're over 60, somewhere in the neighborhood of 1500 calories per day is likely maintenance for you, because the nominal weight loss indicates the participants were actually consuming close-to-maintenance levels.  Either the LC'ers have to consume roughly 200 calories less per day than LF'ies, or they are more prone to lying on food logs (grin).   It's calories and a caloric deficit that elicits weight loss, not insulin.  But that won't stop LC advocates from misrepresenting this study as a shining star for the cause.  More on that last point in a follow up.  Oh ... and the Swedish LCHF trend may be overstated ;-)

35 comments:

Dave said...

Misses the point. Obviously calorie intake is the major determinant of weight loss. But what determines calorie intake in free-living individuals?

Evelyn aka CarbSane said...

Not insulin ;-)

Seriously, I think there are two reasons for spontaneous reduction in intake on LC diets which is why they pretty predictably garner greater early, short-term losses. (1) LC foods are higher as a percent in protein, and (2) Ad libitum eating of "fattening" foods tends to just be a whole lot fewer calories than you think there are.

What you state as obvious many in the LC community still argue against. A certain notorious one leading the pack.

eulerandothers said...

A possible (3) restricting food to a narrow range tends to get monotonous. If you are at all motivated to stay on a diet (because you have lost some weight = good motivator!), you will eat less quantity/calories of what's offered in that narrow range. Simply because it is monotonous!

Dave said...

Insulin is, amongst other things, a satiety hormone. So it certainly plays a role in satiety.

What is the biology underlying (1) and (2)?

Who's the "notorious one"?

Dave said...

By that logic, if you feed a rat nothing but rat chow, it should eventually stave to death.

Dave said...

Starve, not stave...

(almost typed "stave" again ;-)

Sanjeev said...
This comment has been removed by the author.
Sanjeev said...

it wasn't logic, it was a summation of food reward research - a summation of experiments on rats, mice and humans

> should eventually stave to death
this extreme was not discussed in the comment you replied to

> should eventually stave to death
What's observed is that with low reward monotonous diet rats stay at a steady weight.

With a varied, highly-rewarding diet they gain weight, usually fat mass

Stephan Guyenet otlined much of the research on his blog over the last year. YOu If you want to comment knowledgeably on food reward his series is a good place to start.

Sanjeev said...

I don't know if the mechanism behind protein's effects has been thoroughly traced, but we've discussed experiments that demonstrate the effect this blog often.

to the right of the comments, at the bottom (above the flowers) there's a "topics" box. IN there is a link to "protein" ... some of the studies are listed there.

Marie Everington said...

Does having a low natural satiety threshold (gets 'full' easily, sometimes on less than maintenance calories eating ad libitum) mean someone is insulin sensitive rather than resistant?

Hugh Tauerner said...

I'd hardly call 87g carb/day low-carb.

In the 1970s in the UK, the recommendation for type 2 diabetics was to stick to around 50g carb/day.

In just under 2 months running on around 30 - 50g carb/day I dropped my HbA1c from 7.7 (12/2/2012) to 6.9 (2/2/2012) and 3 months further on, (5/10/2012) it was down to 6.0.

I'm no longer on medication -- I stopped taking Januvia and Metformin March 21,2012 as I no longer needed them. My blood glucose results are running in the normal and, at worst, pre-diabetic ranges. The only thing left to bring down is my AM fasting numbers -- I've still got some Dawn Effect going on.

I've only lost about 10lb so far, but I'm still losing albeit slowly. I'm averaging about 1850 calories with 13% carbs, 28% protein and 59% fat. I'll be 62 next week, and was diagnosed with type 2 diabetes some 8 years ago, so I'm well into the target demographic of the study.

At this point, the best thing I can do to keep this under control, apart from carrying on with the LCHF thing is to get more exercise. And I'm working on that.

Hugh Tauerner said...

That was an HbA1c of 7.7 on December 2, 2011. It had damned well be a lot lower than that by December 2012!

Kim said...

My HbA1c in March of 2011 was 13.9. In November it was 5.6. I didn't really count calories but at a primal diet with about 20-30 grams of carbs per day and quite a bit of fat. No meds during that time. I quit taking metformin in March of 2011.

Nigel Kinbrum said...

"By that logic, if you feed a rat nothing but rat chow, it should eventually stave(sic) to death."
On monotonous diets, animals eat to live.
On CAF diets, animals live to eat.

Mike deCock said...

My wife is one of those people with a very well regulated sense of satiety. Sometimes she'll literally leave a single bite of food on her plate, even if she's really enjoying it. Never in my life have I considered it appropriate to do such a thing.

The most obvious difference between the way we eat is speed. I usually wolf down my meal in 3 minutes and she'll still be chewing away, savoring each bite 30 minutes later. I'm not exaggerating.

I've always had limited success while free feeding on low carb or paleo diets. When I add calorie counting to manage my portion sizes, I can get down to a normal BMI range without feeling deprived.

After noticing the drastic difference in satiety mechanisms between me and her, I stopped feeling like calorie counting was such a bad idea for the long term. Whatever is "working" in her is "broken" in me so I use the scale (both in the bathroom and in the kitchen) to determine my portion sizes. Perhaps that is neurotic to some, but for me has become as normal as following a recipe when cooking a meal. I just have an extra step to weigh out a predetermined portion when I put it on my plate.

Whether it's overall insulin sensitivity or just plain giving your gut and brain enough time to register the calories you've just consumed, I don't know. But for what it's worth, when I'm done wolfing down my meal, I usually remain a bit peckish for about 5 more minutes. After that I'm perfectly satisfied until my next meal.

Nigel Kinbrum said...

"I'd hardly call 87g carb/day low-carb."
I would. Anything under 120g/day (typical brain consumption) is low-carb. 30-50g/day is very low-carb/ketogenic.

"I stopped taking Januvia and Metformin March 21,2012 as I no longer needed them."
And your criterion for "no longer needed them" was...?

"I've still got some Dawn Effect going on."
You still need something. Metformin is one of the safest insulin sensitisers around. Why stop taking it? Once you've normalised your insulin sensitivity by other means (exercise, improved Vitamin D3/magnesium status), then you can stop taking Metformin. See Insulin Resistance: Solutions to problems.

Tonus said...

"But for what it's worth, when I'm done wolfing down my meal, I usually remain a bit peckish for about 5 more minutes. After that I'm perfectly satisfied until my next meal."

Same for me. I also tend to eat very fast, and can continue to eat even after finishing a meal. But if I wait 10-15 minutes, my hunger and any desire to eat are gone. Sort of like waiting for the satiety signal to catch up.

Evelyn aka CarbSane said...

Good point!

Evelyn aka CarbSane said...

The notorious one? Taubes of course!! Are you new here? If so, welcome! I've had other Daves so sorry about that. My ;) winky there was to denote sarcasm. I agree, insulin is a satiety hormone, but I do wonder how much of satiety is linked to it per se. The underpinning of (1) Is that LC foods tend to be higher in protein unless one comprises one's diet of heavy cream and butter. Most when they do Atkins style diets for the first time will eat more meat, tuna, chicken, eggs, even bacon where before they were eating Doritos and such. (2) Is just my observation and experience. I think if you've been eating LF for so long you tend to overestimate the calories you're eating of foods like bacon and steak. As my follow-up post worked through, adn has been seen in other studies, HF "diets" often contain the same amount of fat in absolute amounts as baseline.

Evelyn aka CarbSane said...

Welcome Hugh! I'm not against LC to treat/manage diabetes. Rather the opposite. Mostly I was getting at was overselling this particular diet based on this particular study, and that the calories are rather high *on average*. For me, 1600/day would not produce any weight loss, and back in 09 would have caused gain despite considerable weight to possibly lose. My metabolism has bounced back a bit and I might lose like a pound a month on 1600. I also think Nigel raises a good point. The dawn phenomenon is hepatic IR related. If you read about the blog a bit you'll find that I believe the evidence is overwhelming that hyperglycemia is the end-line symptom. VLC manages the symptom without treating the cause. So long as you are in caloric deficit and losing weight it will appear to be working, but what I think the Westman study (linked to through the reference chain in my follow-up) shows is that there seems to be a point of diminishing returns. Certainly seeing long term low carbers who weren't diabetic struggle with IR related conditions/phenomena (like rising FBG's) is cause for pause. This might be a good read: http://carbsanity.blogspot.com/2011/01/insulin-understanding-its-action-in.html

Evelyn aka CarbSane said...

That sounds phenomenal and I wish you continued success! This is certainly better than the average outcome in Westman's study. A common misconception is that I'm anti-LC which I am not.

Welcome to the Asylum!

Alex said...

Insulin as satiety hormone completely baffles me, because a starchy meal will make me voraciously hungry a couple hours later. Whereas a steak topped with a big pat of butter will keep me sated for 5+ hours, and when hunger does return, it's very gentle.

Sanjeev said...

Makes total sense to me because of the reported experiments.

On a lower level there's my anecdote; while experimenting with Stephan's strictest-level low reward diet I went very low fat for 6 months ... chicken & turkey breasts and tasteless protein powder for my protein sources. yellow potatoes for starch, spinach for the vegetable. I was probably at 10% fat for 6 months.

When I stuck to that I hunger was rare. I occasionally went 800 cals in a day with zero hunger.

The only times I was hungry was the day after adding some fat. If I added 4 eggs or some steak (no sugar, no fruit, no fructose) I was RAVENOUS the day after.

There was the one month variation on Stephan's #5 when I found some really cheap stew beef at the butcher's and bought and froze a bunch of it. I did that as the diet's meat for 3 weeks.

The sensation of hunger was pretty common for the first week of that. If I had less tolerance for it I would have abandoned the diet completely.

This was one reason I tried to never, ever cheat. This experience added to previous experiences that showed me that planned cheats don't work for me.

I have always been skeptical of the 90 minute "pre-load" feeding experiments[0] but this personal experience raises my skepticism to new heights. These experiences also lead me to heavily discount the standard 30 day studies. That's just long enough


[0] the ones that give huge support to the volumetrics type diets

Sanjeev said...

> starchy meal will make me voraciously hungry a couple hours later

You mean, when the insulin's at its lowest is when you get hungriest?

> Insulin as satiety hormone completely baffles me

Sanjeev said...

> Whereas a steak topped with a big pat of butter will keep me sated for 5+ hours,

If you were spoofing Jimmy you Poe'ed me

But remember that in fact beef raises insulin as much as many carbs. the low carb rationale that "glucagon is the anti-insulin that's released in response to meat" does not hold up because in humans glucagon has little (not zero, but low) effect outside the liver

I'm personally wondering now if ASP has some satiety effects like insulin, but because dietary fat clearance is so much slower than dietary starch clearance the ASP satiety lasts longer as well.

Sanjeev said...

glucagon effect on adipocytes

or outside the liver

Evelyn aka CarbSane said...

Yep guys, I've read many times about the Japanese practice of leaving the table when 85% full or somesuch. I think the underlying reason being most of us modern humans (who don't actually have to hunt or gather) don't have very well honed satiety signals ... but just give them a little time to kick in and we're golden.

I think the same works for hunger pangs. Especially when I'm puttering about the house I get "hungry". I don't answer the call the first time with the promise to myself that if I'm truly hungry I'll eat something later. Usually it's at least an hour if not several before that happens.

Alex said...

I'm not spoofing Jimmy. The combination of fat and protein is extremely satiating for me, but it doesn't mean I can stuff my face with hypercaloric quantities of buttered bacon and expect my weight to stay the same. I eat ad libitum, but I tend to eat in a habit pattern that keeps my weight very stable. Every time I try adding starch back into my diet on a regular basis I gain weight because starch up-regulates my appetite. It just seems odd to me that insulin would be a satiety hormone when the foods that most greatly affect insulin levels are the ones that cause the greatest hunger.

bentleyj74 said...

I'm reluctant to say insulin plays NO role as anything that has a tie to intake that can act on/in the brain strikes me as a reasonable participating element...I'm just equally reluctant to say it's so straight forward because it obviously isn't.

Gys de Jongh said...

There is an article on Diabetes In Control here :

http://www.diabetesincontrol.com/articles/diabetes-news/12814-questioning-carbohydrate-restriction-in-diabetes-management

Quote
Patients with type 2 diabetes are usually advised to keep a low-fat diet. Now, a study shows that food with a lot of fat and few carbohydrates could have a better effect on blood sugar levels and blood lipids.
Unquote

But if you have a look at the Table on Page 8 (Which is also in the link you provided) you can see that Nystrom FH, the local Low-Carb guru, did not found *any* parameter with significant p value for the difference between a Low-Carb and a High-Carb diet. All the p-values-d are either larger than 0.05 or smaller than 0.95. Or he did not prove that there was a difference and he did not prove that there was no difference between the two diets.

I agree with you that the only thing that matters is the more than reasonable amount of calories, the macro break down has no effect.

Yet Diabetes In Control says : "that food with a lot of fat and few carbohydrates could have a better effect on blood sugar levels and blood lipids"

I just wrote a letter to David Joffe, the Editor in Chief, CDE, FACA, BSPharm of Diabetes In Control to ask him what I missed (?)

Gys

bentleyj74 said...

The Kitavan/Tokelauan contrast has always bugged me specifically in regard to diabetes.

Lesley Scott said...

I have that same issue that I have to manually limit my portions b/c for some reason my internal "you're full" meter just doesn't ding. I've learned through trial and error - and getting on the scale each week - the types of meals that are most likely to keep me satiated even if right after them, if left to my own devices, I would happily wolf down seconds. I've been actually working lately with trying to notice hunger/eat cues when they arise, but then deciding if I want to follow them. This is proving both easier & harder than I would have predicted, but I figure anything that makes me less asleep when it comes to food is probably a good thing.

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