Tag Archives: insulin

Saturated fat, cholesterol, and carbohydrates

“You catch more flies with honey…”

^^^good policy in general, but especially for debating in the realm of nutritional sciences.

 

A short while back, Nina Teicholz discussed low carb ketogenic diets and plant-based diets with John Mackey.  Although I disagree with the dichotomy (keto vs. plant-based), it’s well-worth a watch:

 

 

Three topics that could not be avoided in such a discussion: saturated fat, cholesterol, and carbohydrates.

 

 

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Meal frequency, intermittent fasting, and dietary protein

Dietary protein “requirements” are some of the most context-dependent nutrient levels to decipher, and depend largely on energy balance and even meal frequency.

An objective look at intermittent fasting (Alan Aragon, 2007)

Meal frequency and energy balance (Lyle McDonald, 2008)

New study: “Increased meal frequency attenuates fat-free mass losses and some markers of health status with a portion-controlled weight loss diet” (Alencar et al., 2015)

This wasn’t well-received in social media because bro-science & many low carb advocates say grazing is no longer in vogue — “it’s much better/healthier/whatever to eat once or twice daily, because intermittent fasting and all that jazz” …however, this may be problematic when it comes to meeting overall protein needs, which is particularly important when you’re losing weight.

 

 

The study: 2 vs. 6 meals per day, crossover.  

Conclusion: “On average, fat-free mass (FFM) decreased by -3.3% following the 2 meals/d condition and, on average, and increased by 1.2% following the 6 meals/d condition (P<.05).”  

 

fat-free mass

 

In other words, 6 meals per day was better for body composition than 2 meals per day.  But context is everything, and this hypothesis has been tested from a variety of different angles, so what does it mean?  

The relevant context here: 1) big energy deficit (1200 kcal/d for obese women is a pretty low calorie intake); and 2) “adequateTM” protein intake (75 g/d).

The standard dogma says that in the context of an adequate protein hypocaloric diet, meal frequency matters a LOT, whereas with high protein, it doesn’t matter as much.  Theory being that with an “adequate” (read: too low?) overall protein intake, the fasting periods are simply too long with only two meals per day; you need either: 1) higher protein intake; 2) increased meal frequency; or 3) more calories (ie, smaller energy deficit).  

In this study, BOTH diets suppressed insulin and induced weight loss, but the increased protein feeding frequency skewed the weight loss to body fat while preserving fat-free mass.   I actually agree with a lot of the bro-science in this case, and also think that 75 grams of protein is not enough in the context of a big energy deficit (if body composition is a goal).    




 

Historical precedence?

 

Meal frequency and weight reduction of young women (Finkelstein et al., 1971)

Relevant context:  6 vs. 3 meals per day (3 meals per day may not seem like that many more than 2, but it significantly cuts down on the duration of time spent with no food or protein).

Smaller energy deficit: 1700 kcal/d in overweight patients is less of a deficit than 1200 kcal/d in obese patients.

Higher protein intake: 106 – 115g/d.

Result: nitrogen balance (a surrogate for the maintenance of muscle mass) and fat loss were similar in both groups.  This study fixed two problems in the abovementioned study: 1) 3 meals is better than 2 in the context of an energy deficit; and 2) protein intake was higher.

 

And again here, with 3 vs. 6 meals per day (Cameron et al., 2010), just to make the point that 3 meals per day is better than 2 for preserving lean mass in the context of an energy deficit.

 

The effect of meal frequency and protein concentration on the composition of the weight lost by obese subjects (Garrow et al., 1981)

This study tested the opposite extremes: super-low calorie intake (800 kcal/d), much lower protein intakes (20g – 30g/d), and 1 vs. 5 meals per day.

Result: “a diet with a high-protein concentration, fed as frequent small meals, is associated with better preservation of lean tissue than an isoenergetic diet with lower-protein concentration fed as fewer meals.”

It basically confirmed all of the above.

 

Protein feeding pattern does not affect protein retention in young women (Arnal et al., 2000)

1 vs. 4 meals per day; and 70 grams of protein but no energy deficit (~2000 kcal/d isn’t very hypocaloric for lean young women).  In this study, no effect of meal frequency was seen, likely because 70 grams of protein isn’t inadequate when energy intake isn’t restricted.

 

 

 

1. PROTEIN “NEEDS” ARE HIGHLY CONTEXT-DEPENDENT

2. NEED =/= OPTIMIZATION

3. MEAL FREQUENCY & meal timing and peripheral circadian clocks > “MACRONUTRIENTS”

 

If you’re losing weight (ie, in an energy deficit), then intermittent fasting is cool if protein intake is high (above “adequateTM“)… the bigger the energy deficit, the more protein is necessary to optimize changes in body composition.

 

How much is ‘enough?’  Sorry, can’t give you a gram or even gram per pound of body weight answer… but if you’re losing weight and seeing no discernible effect on body composition (muscle vs. fat mass), then it may be prudent to consider eating more protein-rich foods… and paying more attention to sleep quality (which also greatly impacts nutrient partitioning).

No amount of protein will help you if circadian rhythms aren’t intact!!!

 

 

further reading:

Yes, it’s a high protein diet (Tom Naughton, 2015)

Protein requirements, carbs, and nutrient partitioning

Dietary protein, ketosis, and appetite control 

 

 

calories proper

 

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Good calories

Nuts are good calories.

I’m not a big fan of the omega-6 fatty acid linoleate, but that’s largely in the context of processed foods and confectioneries, where it’s more than likely no longer in it’s native form (Dc9,1218:2n6)… but in the context of unprocessed whole foods (eg, nuts), a little n6 is fine imo.

What are good calories?  They’re nutrient-dense and don’t generally lead to overeating… like the opposite of soda and junk food.  Nuts are low carb and many are highly ketogenic (eg, Brazils, macadamias, and pecans are ~90%fat).  Mr. Ramsey may even approve of macadamias because they have virtually zero PUFAs.

BONUS: magnesium, copper, selenium, many trace minerals and micronutrients, etc., etc.

I’m not saying you should crack open a can of Deluxe Mixed Nuts and sit down with nothing to do other than NOM NOM NOM ALL THE NUTZ.  I’m talking about a few nuts with a meal.  Possibly earlier in the day (coinciding with LIGHT); nuts are tryptophan-rich and this may improve melatonin onset -> good for circadian rhythms:

 

nuts and melatonin

 

 

Appetitive, dietary, and health effects of almonds consumed with meals or as snacks: a randomized controlled trial (Tan and Mattes, 2013)

In this study, the participants were instructed to eat a serving of almonds (~43g, ~245 kcal) daily for four weeks, at different times of the day (with breakfast, midmorning snack, lunch, or afternoon snack).

Regardless of when the almonds were consumed, the calories were practically completely compensated for.  The participants unwittingly ate less other stuff.  And in 3 out of 4 of the conditions, the almonds were so satiating that the participants actually ended up eating fewer overall calories.

That, in a nutshell, is what I call “good calories,” and I don’t think it’s too far from Taubes’ original definition… especially because it was accompanied with [modest] reductions in body fat (NS).  To be clear, they were instructed to eat more (in the form of almonds), but ended up eating less, BECAUSE ALMONDS.  This wasn’t a cross-sectional study, so no healthy user bias or other obvious confounders.

Further, the participants clearly weren’t obesity resistant.  They were overweight, obese, or lean with a strong family history of type 2 diabetes.  Sam Feltham would’ve been excluded.

This is not an isolated finding: another study showed a dose-dependent response to almonds: 28g or 42g consumed in the morning resulted in a compensatory reduction of hunger and total energy intake at lunch and dinner (Hull et al., 2014).  This wouldn’t happen with soda or junk food.

 

 

Another study tested ~350 kcal almonds daily for 10 weeks and concluded: “Ten weeks of daily almond consumption did not cause a change in body weight. This was predominantly due to compensation for the energy contained in the almonds through reduced food intake from other sources” (Hollis and Mattes, 2007).

Almonds vs. complex carbs? Almonds, FTW.

1 Brazil nut daily: “After 6 months, improvements in verbal fluency and constructional praxis (two measures of cognitive performance) were significantly greater on the supplemented group when compared with the control group.”    ONE FRIGGIN’ NUT!

 

http://www.dreamstime.com/-image11630100

 

Walnuts protect against alcohol-induced liver damage (in rats) (Bati et al., 2015) and may improve brain health (in humans) (Poulose et al., 2014).

Pistachios improve metabolic and vascular parameters (Kasliwal et al., 2015).

Meta-analysis (not an intervention study): nut consumption is associated with lower risk of all-cause mortality (Grosso et al., 2015). Yeah yeah yeah, I know, correlation =/= causation.  Whatever.

Nuts are good calories.  That’s all I’m saying.

 

Tl;dr: buy these and one of these, not this.

 

 

calories proper

 

 

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Carbs: Low vs. Lower

 

 

This was met with much backlash from the low carb cavalry, because, well, if low is good then lower must be better

I’m not anti-keto; but I’m not anti-science.  FACT.  

 

“…some people are not genetically equipped to thrive in prolonged nutritional ketosis.” –Peter Attia

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LIGHT, Leptin, and Environmental Mismatch

For a long time, the melanocortin system was basically thought to control the color of skin and hair.  It still does, and many redheads are redheaded due to polymorphisms in one of the melanocortin receptors.

Fast forward to 2015: to make a long story short, melanocortins are HUGE players in circadian biology.

 

POMC ACTH a-MSH

 

Brief background (also see figure above):

Fed state -> high leptin -> a-MSH -> MC4R (the receptor for a-MSH) = satiety, energy production, fertility, etc.

Fasted state -> low leptin -> AgRP blocks MC4R = hunger, energy conservation, etc.

MC4R polymorphisms in humans are associated with obesity.  Melanotan II causes skin darkening (marketed as “photoprotection” [no bueno, imo]), enhanced libido, and appetite suppression.

 

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“Afternoon diabetes” and nutrient partitioning

Don’t exacerbate afternoon diabetes with afternoon carbs.

Skeletal Muscle
As discussed previously [at length], insulin sensitivity in skeletal muscle follows a circadian pattern: starts out high in the morning and wanes throughout the day.

Diurnal variation in oral glucose tolerance: blood sugar and plasma insulin levels, morning, afternoon and evening (Jarrett et al., 1972)

 

impaired circadian glucose tolerance in the morning

 

Diurnal variation in glucose tolerance and insulin secretion in man (Carroll and Nestel, 1973)

Circadian variation of the blood glucose, plasma insulin and human growth hormone levels in response to an oral glucose load in normal subjects (Aparicio et al., 1974)

Adipose Tissue
And insulin sensitivity of adipose tissue goes in the opposite direction: starts out low, and increases as the day progresses.

Diurnal variations in peripheral insulin resistance and plasma NEFA: a possible link? (Morgan et al., 1999)
The studies were standardized for a period of fasting, pre-test meal, and exercise… Following insulin, NEFA fell more slowly in the morning (149 uM/15 min) than in the evening (491 uM/15 min).

Diurnal variation in glucose tolerance: associated changes in plasma insulin, growth hormone, and non-esterified fatty acids (Zimmet et al., 1974)
Adipose tissue insulin sensitivity is greater in the evening.  FFA are higher, and get shut down more rapidly, after a carb meal in the evening.

Summary: to minimize blood glucose excursions and proclivity for fat storage, eat more calories earlier in the day; this is circadian nutrient timing.  And according to the Alves study, a low-carb protein-rich dinner best preserves lean tissue during weight loss.

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Ketoadaptation and physiological insulin resistance

This is where the magic happens.

Rat pups, fed a flaxseed oil-based ketogenic diet from weaning onward – note the drop-off in ketones after 2 weeks (Likhodii et al., 2002):

flaxseed ketogenic diet

What happened on day 17?

Patient history: these rats have been “low carb” their whole lives.

Side note: flaxseed oil is very ketogenic! (Likhodii et al., 2000):

ketogenic rodent diets

Flaxseed oil-based ketogenic diet produced higher ketones than 48h fasting; the same can’t be said for butter or lard.  PUFAs in general are more ketogenic than saturated fats in humans, too (eg, Fuehrlein et al., 2004):Saturated polyunsaturated ketones

Crisco keto (adult rats) (Rho et al., 1999):

shortening-based ketogenic diet

suspect those two rogue peaks were experiment days…

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2 New Diet Studies

*ugh* journalists

I’m talking to you, Mandy Oaklander!

Regarding the new low carb vs low fat study, she writes: “Popular diets are pretty much the same for weight loss, study finds.

Effects of low-carbohydrate and low-fat diets: a randomized control trial (Bazzano et al., 2014)

Further, “An earlier study in Annals of Internal Medicine did find that low-carb dieters lost slightly more weight than low-fat dieters after one year. The study today reached similar conclusions, but the differences in weight loss were not significant.”

Perhaps Mandy just doesn’t realize there’s a difference between significant, as in “meaningful,” and significant, as in “P<0.05.”  Pro-tip: you can tell them apart relatively easily, because the latter is usually accompanied by a cute little asterisk.  For example, the differences in weight loss were quite statistically significant (P<0.05):

Bazzano BW
She goes on to say “After a year follow-up, some of those pounds crept back for people on both diets…”

To that I say: yeah, but fat mass continued to decline in those on the low carb diet, meaning some of that weight re-gain was muscle:

Bazzano FM

So, between 6 and 12 months, carbs and calories were creeping up in the LC group, yet fat mass was still declining.  Perhaps this way of eating improved their metabolism, or restored the ability to effectively partition nutrients.

***in real-time: at this point, I realize that Mandy was actually talking about the other study, which she was covering accurately.  Sorry, Mandy!***

Bazzano PA

…so maybe the low-carb (LC) diet improved muscle mass because it was also high protein? …perhaps, but 19% vs 24% (71 vs 85 grams) isn’t a very big difference.  Alternatively, since the LC group really just maintained absolute protein intake (86 grams at baseline, 85 at month 12), whereas low-fat (LF) dieters decreased (86 grams at baseline, 71 at 12 months); perhaps this is why LF lost muscle mass..?  Still, those changes in protein intake are small, and I think people can be too quick to chalk up the benefits of LC to “high protein.”

In sum, this is actually one of the more “pro” LC studies.  And it wasn’t even a huge difference in carbs: 198 vs 127 grams/d at month 12 (54% vs 34%).  Big difference in fat mass; and CRP, a marker of inflammation, even declined in the LC group.

Low fat diet advocates have been giving me headaches for years… the low fat diet caused headaches (P<0.05):

Adverse Events 1

 

 

Adverse Events 2

The study Mandy was actually talking about: Comparison of weight loss among named diet programs in overweight and obese adults: a meta-analysis (Johnston et al., 2014)

It was a meta-analysis, which is just about the only type of study capable of taking down LC.

 

 

…but at least it had this cool chart (modified):

cool chart (modified)

cool chart (modified)

 

*ugh* scientists

crap

The macro’s in “Low fat” overlap with “Moderate,” implying “Low carb” is “EXTREME”  …the authors’ bias is subtle, I’ll give ‘em that, but I’m getting too old for this.

Dear Obesity Researchers,

If you want to design a study showing a low fat diet is as good as low carb for fat loss, here’s your best bet: recruit young, exercise-tolerant overweight patients who aren’t on any meds.  PROOF (see Ebbeling study).  Or find 10 similar ones and write up a pro-LF meta.

If you want to show low carb is better, recruit patients with obesity.

 

calories proper

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Cyclical ketosis, glycogen depletion, and nutrient partitioning

Meal & exercise timing in the contexts of “damage control” and nutrient partitioning are frequent topics on this blog.  I generally opt for a pre-workout meal, but nutrient timing hasn’t panned out very well in the literature.  That’s probably why I’m open to the idea of resistance exercise in the fasted state.  A lot of pseudoscientific arguments can be made for both fed and fasted exercise, and since a few blog posts have already been dedicated to the former, this one will focus on the latter.

The pseudoscience explanation is something like this: since fatty acids are elevated when fasting, exercise in this condition will burn more fat; and chronically doing so will increase mitochondria #.  The lack of dietary carbs might enhance exercise-induced glycogen depletion, which itself would bias more post-workout calories toward glycogen synthesis / supercompensation.  Much of this is actually true, but has really only been validated for endurance training (eg, Stannard 2010, Van Proeyen 2011, & Trabelsi 2012; but not here Paoli 2011)… and the few times it’s been studied in the context of resistance exercise, no effect (eg, Moore 2007 & Trabelsi 2013).  However, there are some pretty interesting tidbits (beyond the pseudoscience) which suggest how/why it might work, in the right context.

Exercising fasted or fed for fat loss?  Influence of food intake on RER and EPOC after a bout of endurance training (Paoli et al., 2011)

John Kiefer, an advocate of resistance exercise in the fasted state, mentioned: “the sympathetic nervous system responds quicker to fasted-exercise. You release adrenaline faster. Your body is more sensitive particularly to the fat burning properties of adrenaline and you get bigger rushes of adrenaline.”

Much of this is spot on.  That is, ketogenic dieting and glycogen depletion increase exercise-induced sympathetic activation and fat oxidation (eg, Jansson 1982, Langfort 1996, & Weltan 1998).

The question is: can this improve nutrient partitioning and physical performance?  Magic 8-Ball says: “Signs point to yes.”  I concur.

Contrary to popular beliefs, glycogen depletion per se doesn’t harm many aspects of physical performance.  A lot of fuel systems are at play; you don’t need a full tank of glycogen.

Effect of low-carbohydrate-ketogenic diet on metabolic and hormonal responses to graded exercise in men (Langfort et al., 1996)

High-intensity exercise performance is not impaired by low intramuscular glycogen (Symons & Jacobs, 1989)

Increased fat oxidation compensates for reduced glycogen at lower exercise intensities (eg, Zderic 2004), and ketoadaptation may do the same at higher intensities.

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Ketosis in an evolutionary context

Humans are unique in their remarkable ability to enter ketosis.  They’re also situated near the top of the food chain.  Coincidence?

During starvation, humans rapidly enter ketosis; they do this better than king penguins, and bears don’t do it at all.

Starvation ketosis

 

Starvation ketosis

Humans maintain a high level of functionality during starvation.  We can still hunt & plan; some would even argue it’s a more finely tuned state, cognitively.  And that’s important, because if we became progressively weaker and slower, chances of acquiring food would rapidly decline.

Perhaps this is why fasting bears just sleep most of the time: no ketones = no bueno..?

Observation: chronic ketosis is relatively rare in nature.  Angelo Coppola interpreted that to mean animals may have evolved a protective mechanism against ketosis (if you were following along, please let me know if this is a misrepresentation).

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