The Starch Satiety Shootout: Potatoes, Baked or Mashed, Pasta, Brown Rice or Even White Bread? What's the Best After a 12h Fast? Plus: Science Round-Up Preview!

Pasta! From a satiety perspective even white bread would be a better choice for breakfast.

It's one of those Thursday's where I am alone here at the SuppVersity - no Adelfo Cerame Jr. guest lecture today. But don't worry, there will not only be another guest post next Thursday, but both, today's SuppVersity post, which is actually related to Adelfo's "Carbophobia" post from last week, as well as the SuppVersity Science Round-Up  with Carl Lanore (live at 1PM EST on the Super Human Radio Network), will compensate at least somewhat for Adelfo's absence.

Apropos Science Round-Up, I am absolutely not sure where today's show will be heading to, but I can tell you that by now it looks as if we would start out with a very recent study on the leucine <> leptin connection and it's role in getting big and ripped.

It stands to reason that the big "L"s are not going to get the job done without some sort of workout, we will then segue into the acute hormonal effects of doing cardio before vs. after a workout - something I suppose many of you who have listened to the last installment and read the follow-ups (the Seconds and the post on PGC-1 alpha-4), here at the SuppVersity, will be intrigued to hear and something on which I want to provide a little more background information with respect to the role of fasting, overall energy intake, glyogen depletion, stress and a couple of other things that will primarily effect your luteinizing hormone levels and are thus equally important for male and female SuppVersity students.

I am honestly not sure how much time will be left, afterwards, but either live at 1PM EST, or as part of tomorrows "Seconds" you will also get the chance to learn something about the little known link between nicotine (as in cigarettes) and brain aromatase, the muscle building effects of exercise induced nNOS and the certainly not advisable, but probably likewise anabolic effects of capsaicin injections. And while there is more on the list, I guess this is enough for a preview... unless you were waiting for me to mention the endocrine disrupting effects of bottled water? No!? Well, then let's finally get to the actual post ;-)

Judging carbohydrates by their GI is like adopting another man's prejudice

As I already mentioned today's post is in a way an indirect follow up on Adelfo's confession that his love-and-hate affair with carbohydrates turned into a true friendship now. I mean starches are carbs and though Adelfo explicitly said that he says a place (in moderation) for all of them in his diet, it would be nice to know a little more about the differences between the dreaded potatoes, of which I have argued before that it is in your own hands whether they will (French fries, meshed potatoes, puree, etc.; "The Potato Manifesto") turn into a problem, or not, the demonized white bread and the "healthy" - since organic and brown - starch from pasta and rice.

I guess Allan Geliebter Michelle, I.-Ching Lee, Mariane Abdillahi and James Jones from the New York Obesity Nutrition Research Center at the St. Luke’s-Roosevelt Hospital Center that's part of the Columbia University College of Physicians and Surgeons in New York, when they devised the experimental procedures for their latest study (Geliebter. 2012). And in fact their approach to the problem appears to be pretty down to earth. Instead of just measuring insulin, glucose and what-not - we have had other scientists do that before - they simply fed their twelve healthy normal-weight participants (6 male, 6 female; mean age 25.6 years,  mean BMI 22.4kg/m², mean percent body fat 19.0%) who were recruited from the Columbia University community equienergetic portions (240kcal) of starch-rich side dishes:

• baked potato, no skin - nutrient composition as
• mashed potato, instant - Betty Crocker Idaho potato buds
• brown rice - Carolina natural whole grain brown rice
• pasta - Bionature organic pasta
• white bread - Wonder Classic Giant*

As the (*) indicates, the white bread was in there mainly as a GI standard (you usually supply GI values w/ reference to either glucose or white bread) and in order to make sure that it had it's 50g of carbs, just like all the other meals, the scientists needed so much that the overall caloric value of this "standard" meal was 33kcal higher (keep that in mind, thats ~12.5% and could therefore very well make a difference). In order to exclude any confounding variables, the water content (400g) and salt content were likewise standardized - both were added if necessary.

Pasta, rice and potatoes for breakfast?

In know, its not realistic that you have only pasta, rice, potatoes or white bread ... hold on, I know a couple of people in fact a large amount of my students eats nothing but white bread right from the baker for breakfast in their first lecture of the day :-( So it's not that unrealistic: At least we could ask ourselves would they be better off, if they ate potatoes, pasta or rice as their first meal after a 12h overnight fast, when maximal satiety is what we are looking for?

Figure 1: Hunger ratings and desire to eat from 10min before to 120min after the breakfast (Geliebter. 2012)

Well let's see, what do we have here? First off, one thing that's not in any of the graphs is the statistically significant gender bias, with the women experienced greater fullness across the test meals than men (p < 0.01). As far as the rest is concerned, the ...

• AUC of the appetite ratings from 10 minutes before to 120min after the ingestion of the meal did not differ, and still there was a...
• lower ‘desire to eat’ AUC following bakedpotato compared to pasta (p = 0.027) and brown rice (p = 0.004) and a much less significant advantage for rice over pasta (p = 0.041);
• changes in fullness, however, did not differ between test meals (not shown in figure 1)

So, obviously the baked potato, which was incidentally the only food that had no nutrition label (all the rest was packaged branded and labeled), was the subjectively most satiating starch source, followed by rice and trailed by the mashed potatoe and the distant (given the overall difference) "healthy" pasta.

So, to get back to my research question, whether my real students (not you, but those at the University), would be better off eating another bland starch instead of their buns, the answer would be yes - in the long run, both brown rice and baked potatoes would qualify. 

Potato-ish insulin spikes and low GI white bread

What is interesting though, is that the spike in the "How much food could you eat now?" graph in figure 2 coincides with the early insulin spike in response to the potato meals. If you are into grazing like a cow, i.e. if you like to eat bazillions of small meals, all day long, potatoes may therefore be not your best choice.

Figure 2: Insulin after breakfast,estimation how much the participants believe the could eat and calculated GI values (based on the measured glucose response; Geliebter. 2012)

What could be downright surprising for some of you, I guess, is yet probably the fact that anyone adhering to a low GI diet, would actually have to copy my students and eat the white bread, which had the lowest GI of all the test meals ... but I guess this and the fact that pasta by far the least satiating of the 4 meals had an only 7.6% higher GI should be the nail to the real-world relevance of the glycemic index, anyway.

The non-significance of the glycemic index  was also evident during the following lunch, where the subjects were allowed to chose or simply eat both of an on an individual base already non-manageable amount of chicken or tuna salad with mayonnaise, celery, salt, and pepper that were served "in covered serving containers with openings on top to reduce visual feedback" (Geliebter. 2012) and bundled with six slices of wheat bread and six slices of seedless rye bread:

"The group mean IAUC glucose and GI using the white bread standard and adjusted for the glucose load standard are listed in table 2 . Mashed potato had the highest GI of the side dishes. The correlation between the group mean fullness AUC and the group mean GI was 0.59. The correlation between the group mean fullness AUC and the group mean lunch energy intake was –0.21. These corrrlations are not significant." (Geliebter. 2012)

Remember Peter Czerwinski, aka Furious Pete's 900g of protein in 3:30min binge (Furios Pete, 2010)? No? In that case the fact that whey is more insulinogenic than white bread is probably news to you, as well, after all, the video was part of the SuppVersity post discussing that.

So, if you intend to become friends with starches and other carbohydrates, just like Adelfo did, don't judge them by the GI value you've found in whatever online or print source. Don't fear potatoes and if you need something to count to satisfy your OCD tendencies, count total amount carbohydrates (not the rice crumbs), keep the simple sugars in check and match both of them to your personal preferences / needs.

The GI is not the "unit of food quality"

And if that's not enough counting for you, what about counting the nutritional labels on the stuff you buy? The less you have, the better your diet - after all, whole foods you buy at the farmer's market or wherever else you can still get non-industrialized real food, does not have nutritional labels ;-)

References:

• Geliebter A, Lee MI, Abdillahi M, Jones J. Satiety following Intake of Potatoes and Other Carbohydrate Test Meals. Ann Nutr Metab. 2012 Dec 4;62(1):37-43.

EPIC Study Says: Vegetables, Fish, Dairy, Pasta & Rice Reduce, Softdrinks, Processed Meat, Margarine, Spirits and Potatoes Increase Waist Circumference - Really!?

Image 1: The EPIC project unites scientists
from all over Europe (EPIC, IARC. 2011)

I don't know whether it is a good idea, for an anti-epidemiologist like me (I mean, come on, epidemiology vs. controlled experiments is like astrology vs. astronomy) to post this, but a 13-year (1992-2005) meta-analysis (Romaguera. 2011) of data from 48,631 men and women from 5 countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC) study is probably as good as as epidemiology can ever get and with scientists from 12 different institutes all over Europe, there is at least some hope that the results of their investigation into the association of food groups/items consumption "on prospective annual changes in 'waist circumference for a given BMI' (WC_BMI), prox for abdominal adiposity".

Unfortunately the first of the typical shortcomings of EPIC studies (pun intended) like this becomes obvious in the previous citation, already, as the quotation marks before "waist circumference" indicate that the latter "was measured either at the midway between the lowest rib and the iliac crest (the Netherlands, and Potsdam-Germany) or at the narrowest torso circumference (the other centres)." And even worse,

at follow-up examinations, participants in Norfolk (United Kingdom) and Doetinchem (the Netherlands) were measured by trained technicians using the same protocols as at baseline, whereas other centres provided self-reported data.

I guess you can imagine how "exact" these waist circumference are - if not, try and "measure" your personal waist circumference, you will be astonished how easy it is to "diet down" from 35" to 32"... it's a pitty that this kind of 'weight reduction' is not sustainable ;o)

Be that as it may, it argues in favor of the scientists that they did a validity test with 408 men and women from the Danish cohort beforehand and it turned out that "a high correlation between the self-reported and technician measured WC was found". Furthermore, the scientists were able to extrapolate association with baseline BMI and used these later in the regression analysis to make up for potential measuring "mistakes" on part of their subjects. If we thusly assume that at least this part of the data is reliable - I don't think I have to go into any detail as far as notoriously inaccurate food frequency questionnaires are concerned - the study provides some tangible insights into the influence the eating habits of the general population has on the accrual / loss of body fat.

Figure 1: Association (expressed as beta² coefficients, left axis) of certain foodstuffs and beverages (daily consumption in grams, right axis) with increases (positive beta²) and decreases (negative beta²) in waist circumference in 48,631 subjects from the EPIC-DiOGenes project (data adapted from Romaguera. 2011)

If you have a closer look at the data in figure 1, it's quite easy to recognize the major offenders, if you compare the association strengths (beta²) of a given food with the total amount of this foodstuff/beverage in g/day the men and women in the EPIC-DiOGenes project consumed. High beta² values indicate a positive association, which means that study participants who report (!) that they eat much of this food / drink much of this type of beverage, were more likely to increase their waist circumference.

Image 2: If you have any interest in milk, colostrum or dairy in general, make sure you read my recent write-up on milk and milk consumption!

Now, while spirits may have an even higher association with abdominal adiposity than soft drinks, the overall contribution of Jack Daniels and Co to the obesity epidemic, which has a similar handle on Europe as on the US, is nevertheless negligible, because even men "booze" way to seldom to get fat just from booze. On the other hand, the negative association of fish (beta²=-0.05) and waist circumference is much stronger than that of milk, but since fish consumption is equally low for both men and women, chances are that, overall, milk (beta²=-0.01) may contribute just as much or even more to keep (at least some of) Europeans, who love their milk (you can read more on milk if you follow the link beyond image 2) and despise fish, from bursting out of their pants and skirts than fish does, despite having the higher and thus less beneficial beta² coefficient.

I bet, some of you are just about to freak out that both "vegetable oils", as well as pasta and rice and (worst of all) breakfast cereals are associated with reductions in waist circumference. At least in the eyes of the paleo-cultists out there, this may disqualify the study as devil's work ;-) People like Robb Wolf or Matt Lalonde, whose pointed analyses go beyond the common black-and-white cave-paintings you will find on the bazillion of paleo-blogs out there, would yet notice that the men and women in the study actually consumed relatively low amounts of these foods. Roughly 63g of rice and pasta for men and 52g for women is certainly a tolerable amount. And to be honest, I have not seen anybody die from a well filled tablespoon of vegetable oil per day, either ;-)

Almost "experimental" seems the last finding of the study I want to mention, which is the (calculated) effect the replacement of (-100kcal energy from) soft drinks, margarine, processed meat and white breads (the major offenders) with either (+100kcal from) dairy or fruits would have on the changes in waist circumference in the course of one year.

Figure 2: Model calculation of the beneficial (lower beta² coefficients) effects of iso-caloric (100kcal/day) replacements of soft drinks, margarine, processed meat and white bread by fruits or dairy (data adapted from Romaguera. 2011)

As the data in figure 2 goes to show the effect the statistical model predicts that the effects of fruit would be more profound... this, however, is something I dare question, simply because the different macronutrient composition of dairy (moderate protein, moderate fat, relatively low carb) vs. fruit (no fat, no protein, high carb) simply forbids such statistical thimblering that neglects the macronutrient composition and focuses solely on the caloric value... ahh, one last word: Whenever, this crucial distinction between eating calories and eating food (I am starting to think that maybe some of the scientists actually eat calories?) will reach mainstream science, I will immediately let you know ;-)

True or False: Having Your Pasta 'Al Dente' Reduces The Postprandial Glucose Surge. Plus: Do Spaghetti Really Produce a 50% Lower Glycemic Response Than Macaroni?

Is Pasta OK, if it's al dente? Sounds legit, right? How legit does it sound, if I tell you that pasta is ok, anyway?

I am pretty sure you've heard some self-proclaimed expert state: "You know why the Italians ain't fat, although they eat tons of pasta all day, bro? I can tell, ya! It's 'cause they eat them al dente... that means "for the teeth", bro - you know?" I guess you don't mind if I discard the subsequent excursion into Italian cuisine, do I? No? Fine! Bro or not: The reasoning behind the recommendation to eat your pasta "al dente" [=cooked so as to be firm but not hard] doesn't sound that flawed, does it?

I mean, aside from the fact that I have to say that the Italians are not as lean as you Americans apparently believe (31.8 % are overweight and 8.9 % are obese) it sounds legit that the hard pasta will take longer to digest. This would (or should I write "should?") reduce its GI and that in turn should help you to stay / get lean. So what?

Will having your pasta 'al dente' lead to a major reduction in glycemic load?

False. While it sounds totally logical that overcooked pasta should have higher glycemic indices and thus - assuming identical intakes - glycemic loads, a 1986 paper by Wolver et al. shows quite conclusively that this is not the case.

Figure 1: Glycemic response 0-180min after test meals containing 66g of white bread or pasta (dry weight) in 11 non-insulin-dependent and 6 insulin-dependent diabetic patients (Wolever. 1986)

The data in Figure 1 does yet also reveal that there are unexpected differences between different types of pasta, with a mean glycemic responses that is 50% lower for the spaghetti meal than for the macaroni, the difference is even statistically significant (P < .01). Enriching your spaghetti with protein (Figure 1, left), on the other hand, is about as worthless as to cook them for only 5 minutes.

And what about pasta with eggs? As logical as it may seem, Granfeldt, Björck, and Hagander did not observe any differences between regular and egg-enhanced pasty in their 1991 study. This is yet not the only similarity to the Wolever study: White bread easily "outperformed" all the three tested varieties of fresh roll-sheeted linguine (thick, thin, thin with egg) when it came to the postprandial glucose levels. What's new, though, is that the glucose spike was followed by a drop into the hypoglycemia zone.

As useless as the "tricks" may be compared to the "American spaghetti", i.e. white bread, pasta is more or less harmless... unfortunately, the glucose surge is not the only reason spaghetti, macaroni and star pastina end up on your hips pretty easily, which is why I'd still suggest you eat them in moderation (I don't suggest that for white bread - unless you actually want to gain weight, you better don't eat that at all ;-).

Potatoes are harmless and by no means the pro-diabetic obesogenic horror food some people say... unless you juice them, of course (learn more)

Bottom line: It's a matter of taste whether you want to watch the clock closely when you prepare your pasta. If you are really enjoying the mash that's floating around in the steaming water after 15 minutes, go for it. Contrary to potatoes where both cooking time, but more importantly post-processing like mashing can have a major impact on the hyperglycemic effects of the tubers (cf. "The Potato Manifesto"; Part 1, Part 2), it does not really matter for spaghetti. Apropos spaghetti, the statistically significant difference in postprandial glucose levels between spaghetti and macaroni is probably physiologically irrelevant.

The latter cannot be said of the blood glucose surge the subjects in the Wolever study experience after the white bread meal. No wonder that a recent study by Dressler et al. which identified bread, not pasta, as one of those food-likings that distinguish overweight / obese from lean / normal women (Dressler. 2013), is only one of a dozen or more of studies, where (white) bread made it into the real-world Top 3 of the most obesogenic foods.

References: 

• Dressler, Heidi, and Chery Smith. "Food choice, eating behavior, and food liking differs between lean/normal and overweight/obese, low-income women." Appetite (2013).
• Wolever TM, Jenkins DJ, Kalmusky J, Giordano C, Giudici S, Jenkins AL, Thompson LU, Wong GS, Josse RG. Glycemic response to pasta: effect of surface area, degree of cooking, and protein enrichment. Diabetes Care. 1986 Jul-Aug;9(4):401-4.