Category Archives: Energy balance

Exenatide and tapeworms, Op. 116

Posted on October 29, 2012 | 1 comment

The great Dr. Schoeller can polish a turd like no other.  Dale Schoeller’s claim to fame is his extensive work on one of the best ways to measure total energy expenditure in free-living individuals: doubly-labeled water.  In doubly-labeled water, subjects drink stable isotope-labeled water; instead of hydrogen + oxygen = H20, the stable isotope-labeled water is deuterium + oxygen-18 = D218O.  Deuterium is excreted just like hydrogen, in water as urine & sweat.  Oxygen-18 is excreted just like oxygen, in water and carbon dioxide.  So the subjects lose deuterium & oxygen-18 in water at equal rates, but only oxygen-18 in carbon dioxide; so this technique basically measures carbon dioxide production, which is proportional to energy expenditure.  Clever. 

Being that Schoeller practically invented the technique, his interpretation of these total energy expenditure data are not flawed, but that’s not where he went astray.

Alterations in energy balance following exenatide administration (Bradley et al., 2012)

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Posted in Advanced nutrition, diet, Energy balance, insulin

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Metabolic rate per se

Posted on October 17, 2012 | 1 comment

I’m switching to a new email sign-up service and have no idea how to transfer my current list of subscribers.  If you’d like to continue receiving updates, please sign-up again on the right.

Admittedly, the effect of diet on metabolic rate is small (i.e. statistically non-significant in most cases), but its incredible consistency across space and time suggest it could be true.  And given the difficulty of maintaining a reduced body weight after dieting, it might even be important.  The following studies are examples of widely differing subject populations in various metabolic conditions; yet the effects of diet on metabolic rate exhibit a phenomenal degree of similarity.

disclaimer: I don’t know what’s more important – metabolic rate per se, the diet behind it, or the resulting hormonal adaptations.  All of the diets that are associated with a higher metabolic rate are also predicted to result in lower insulin levels and higher fat oxidation.  Thus, we are left with a triumvirate of diet, hormonal milieu, and energy expenditure… all of which are important for body composition and quality of life.

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Posted in Advanced nutrition, diet, Dietary fat, Energy balance, Exercise, insulin, Protein

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[ketogenic] elite artistic gymnasts

Posted on October 12, 2012 | 6 comments

Before you say anything, “elite artistic gymnasts” could probably beat you in a race running backwards.  (with you running forwards.)  They are elite athletes.  And given a sufficient keto-adaptation period, they perform better sans carbs.

Ketogenic diet does not affect strength performance in elite artistic gymnasts  (Paoli et al., 2012)

This study looked at body composition and various performance measures before and after 30 days of a very low carbohydrate ketogenic diet (“VLCKD,” < 25 grams of carbohydrate per day) or a normal diet (“WD,” > 250 grams of carbs per day).  25 grams of carbs is very very low, less than Atkins and Kwasniewski.  On the other hand, 41% protein is pretty high.

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Posted in Advanced nutrition, diet, Dietary fat, empty calories, Energy balance, Exercise, insulin, Ketosis, Protein, TPMC

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The Laws of Energy Balance FTW!

Posted on October 9, 2012 | 3 comments

Weight loss maintenance is not determined by calorie intake… or physical activity… but by The Laws of Energy Balance FTW!!!

Odd, the sensation I felt when reading this news release (gloating?).  As reported at a meeting of the Obesity Society, results from the Utah Obesity Study of gastric bypass patients 2 and 6 years after surgery.  By the 2 year mark, they lost over 100 pounds, or 36% of their starting weight (went from 296 to 189 pounds).  Energy expenditure declined from 2201 to 1736 kcal/day.  Food intake went from 2085 to 1638 kcal/day.  (Hint: it’s no coincidence that energy expenditure and food intake declined to the exact same degree.)  Physical activity and fitness levels increased.

By the 6 year mark, they still weighed 29% less than their starting weight.  N.B. that’s an amazing level of success, it’s virtually unheard of in diet intervention studies.  +1 for gastric bypass; -1 for nutrition.

Here’s what piqued my interest: during the gradual increase from 189 pounds to 210 pounds, which occurred between years 2 and 6 post-surgery, the most significant factor associated with weight regain was not calorie intake or physical activity… it was metabolic rate.  This represents another fail for “eat less move more,” and a win for the Laws of Energy Balance.

So what’s this got to do with The poor, misunderstood calorie?

what we know about metabolic rate:

1)      It’s invisible.

2)      Fructose vs. The Laws of Energy Balance (circa December, 2011): sugar-sweetened beverages can cause fat gain, not by providing excess calories, but by reducing metabolic rate.

3)      Holiday feasts, the freshman 15, and damage control (circa January 2012): overeating a high protein diet causes less fat gain than overeating anything else because it increases metabolic rate.

4)      Missing: 300 kilocalories (circa July 2012):  after losing weight, subjects assigned to the low carb diet maintained a higher metabolic rate than those on an isocaloric low fat diet.

“Eat less move more” is not the answer.  But eating less sugar, more protein, and fewer carbs might be.  Nutrition matters.

calories proper

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Posted in Advanced nutrition, diet, empty calories, Energy balance, gastric bypass, Protein, Sugar, TPMC

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Missing: 300 kcal… AGAIN!

Posted on October 3, 2012 | 6 comments

Or, the curious perils of crappy sleep, part II: calorie-thieving gnomes.

In part I of the Crappy Sleep series, we discussed, among other things, the malevolent metabolic effects of the most utterly abnormal sleep structure (28-hour days, 6.5 hours of sleep per night [~5.6 hours / 24 hours], and dim lighting during the days).  In this study, the sleep was disrupted to a physiologically relevant degree for two weeks: 8.5 vs. 5.5 hours per night; in a cross-over study.

In part I of Missing calories, we discussed the effects of 3 different diets on metabolic rate after weight loss.  In this study, energy balance was assessed during 2 different sleep regimens in dieters in a CROSS-OVER STUDY.  If you haven’t guessed it, I believe a well-designed and executed cross-over study is superior, necessary, and essential for most metabolism-related studies.

Insufficient sleep undermines dietary efforts to reduce adiposity   (Nedeltcheva et al., 2010)

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Posted in Advanced nutrition, diet, Energy balance, Protein, TPMC

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BPA

Posted on September 28, 2012 | 1 comment

Though they won’t kill you [instantly], environmental and dietary xenoestrogens warrant a bit of attention, especially considering their theoretical mechanism of action is, among other things, augmenting insulin secretion.  This is of particular importance given the growing body of evidence of a causal role for insulin hypersecretion in the obesity epidemic (see Barbara Corkey’s 2011 Banting Lecture for an overview).

And this is the SECOND time this year BPA has made headlines.

BPA. Looks like some kind of medieval weapon or something.

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Posted in Advanced nutrition, diet, empty calories, Energy balance, insulin, Sugar, TPMC

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Soda vs. childhood obesity

Posted on September 24, 2012 | 11 comments

What happens if you give skinny kids a can of fully sugared regular soda to drink every day for a year?

What happens if you take the soda away from overweight kids for a year?

The answer to these two questions should be a definitive user’s guide to the question: how bad is soda for my children?   And we got those answers this week.

 

A set of powerful studies were recently published, the likes of which I thought we’d never see.  It’s unethical to assign anyone to start smoking so we can properly study the effects of cigarettes; and before today, I would’ve thought it unethical to assign young children to start drinking fully sugared regular soda.  And not just one or two cans…  over 350.  For the 4 year olds the first study, by the end of the trial they had been on soda for almost a third of their life… during a critical period of development.  Ethics schmethics.  Hopefully this study will never be repeated.

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Posted in Advanced nutrition, diet, empty calories, Energy balance, Sugar, TPMC

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Why diets fail, Op. 106

Posted on September 21, 2012 | 1 comment

Correction: diets don’t fail, dieters do.  And don’t take that the wrong way; adhering to a restrictive diet is one of the most difficult tasks for ANYone; thus, the obesity epidemic.  Some recent insights into diet-induced weight loss success, or lack thereof, have shed a new light on why some dieters adhere and others don’t.

In Insulin resistance, I discussed how insulin sensitivity may influence how well someone responds to a diet.  In brief, insulin resistant obese people do much better on low carb than low fat in a closely controlled clinical setting.  If you’re one of the lucky few insulin sensitive obese people, then simply reducing calories works.  Unfortunately, however, most obese are insulin resistant.

When it comes to devising a weight loss strategy, I’m willing to cut every corner and use every trick in the book to achieve success.  Data in this new analysis came from Chris Gardner’s notorious A to Z study, where patients were given diet books and told to have at it.  It was the weakest intervention in the history of diet studies, but it is exactly what everyone who wants to lose weight does.  And just like in Gardner’s study, most people fail.

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Posted in Advanced nutrition, diet, Dietary fat, empty calories, Energy balance, insulin, Protein, Sugar, TPMC

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Insulin resistance

Posted on September 17, 2012 | 23 comments

Why it is important and what you can do about it, Op. 105

 

This post was largely inspired by a recent manuscript by Chris Gardner.  He’s an outside-the-box thinker and if you haven’t heard of him, check out this YouTube video: The Battle of the Diets: Is Anyone Winning (At Losing?)

Part I.  

Type II diabetes is the clinical manifestation of insulin resistance.  It is preceded by obesity (except in the cases of MONW & NOD), and caused by poor nutrition.  Markers of insulin resistance are: 1) impaired fasting glucose; 2) impaired glucose tolerance; and 3) elevated HbA1c.  THIS is why it is important: in 2009, Barr and colleagues showed a linear relationship between all three of these risk factors and all-cause mortality in the AusDiab study.  All.  Cause.  Mortality.

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Posted in Advanced nutrition, diet, empty calories, Energy balance, insulin, mortality, Protein, Sugar

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A historical argument against caloric equality

Posted on September 10, 2012 | 11 comments

80 years later, a calorie still isn’t a calorie.

Exhibit A.

The treatment of obesity   (Lyon and Dunlop, 1932)

As early as 1932, Lyon and Dunlop recognized that the calories from as little as one slice of bread every day could result in pounds of fat mass gained every year.  For whatever reason, this doesn’t happen to lean people; so they decided to study the effect of different diets on obese subjects in a metabolic ward at the Royal Infirmary.

Their idea of a “diet:” If they could only see how much times have changed!  (this is a hotly debated topic.)

Lyon and Dunlop first tested weight loss vs. total calorie intake.  The diet was roughly 40% carbs, 24% protein, and 36% fat.  Not surprisingly, people fed 800 kcal/d lost more weight than those given 1,000 or 1,200 kcal/d (200 vs. 172 vs. 157 grams of body weight lost per day over the period of 7 – 10 days), confirming that the less you eat, the more weight you lose (duh).  A calorie is a calorie after all, right? …

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