Tag Archives: calories

Paleo Plants and Carnivory

From what I gather, it’s been difficult to pinpoint the role of plants in the diet of our ancestors for a variety of reasons.  For example, evidence of plants on cooking tools and dental remains is suggestive but doesn’t disprove the possibility that said evidence came from preparing the plants for some other purpose (eg, tools, weapons, or medicine), or that the stomach contents of an herbivore was ingested (which gets partial credit).

That said, after reviewing a few studies on the topic (see below), it’s safe to say that plants were eaten, probably frequently, and the types & quantities varied seasonally & geographically.  Collectively, the data suggest we aren’t carnivores.

…you had to have something to hold you over until the next fish fell prey to your deadly hunting spear…

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Skipping meals, intermittent fasting, grazing, etc.

or… Circadian Meal Timing!

They say if you’re going to [intentionally] skip a meal, it should be breakfast – and hey, that’s probably the easiest meal to skip.  However, a recent study showed skipping dinner FTW (well, not exactly).  I’ve never seen a proper study directly comparing the effects of skipping different meals, but here are a few that come close.  The findings may surprise you.

omelette

note: with the exception of Fernemark (Exhibit B), these studies are mostly macronutrient-controlled. That is, protein, fat, and carbs are similar between the groups; the only thing that differs is when they were ingested.  This can be tricky and/or very nuanced in some instances, like if dinner was smaller (fewer calories) but more protein-rich, for example… but in order to include 5 relevant studies and not bore you to death, you’ll have to check the full texts for those details.

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Nutrient Partitioning: …a *very* high protein diet.

Or: what happens when you eat a ton of protein?

RDA: 0.8 g/kg

Active individuals: 1.2-2.0 g/kg (via ISSN)
Comment (1): I think sedentary, physically inactive, and non-exercisers should be in this range to offset disuse atrophy.  And they should exercise.
Comment (2): Do athletes really need more protein than non-athletes?  They have exercise, a powerful anabolic stimulus.  More protein may improve performance or body composition, but they might not *need* it, in terms of nitrogen retention… there’s probably a study on this.

NEED =/= OPTIMIZATION

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Melatonin is the chemical expression of darkness.

Melatonin is secreted from the pineal gland, the seat of the soul, the third eye.   Pinealectomy induces circadian arrhythmia and has interesting effects on adipose tissue biology.

Exhibit A.  In 2004, Alonso-Vale and colleagues showed that 6 weeks after pinealectomy, [melatonin-deficient] rats subjected to fasting exhibited an impaired energy conservation response.  That is, they lost more weight and significantly depleted their adipocytes:

pinealectomy

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Pharmaceutical-grade circadian manipulation.

BMAL1 and CLOCK, ‘positive’ regulators of circadian gene expression, activate transcription of the negative regulators Per, Cry, and Rev-erb.  PER and CRY inhibit BMAL1 and CLOCK, whereas Rev-erb inhibits Bmal1.  It is said that Rev-erb is “an important link between the positive and negative loops of the circadian clock.”  You don’t really need to know any of that to follow this blog post.

circadian genes

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Diet study: American Diabetes Association vs. Low Carb Ketogenic

A randomized pilot trial of a moderate carbohydrate diet compared to a very low carbohydrate diet in overweight or obese individuals with type 2 diabetes mellitus or prediabetes (Saslow et al., 2014)

Disclaimer: this study was not ground-breaking; it was confirmation of a phenomenon that is starting to become well-known, and soon to be the status quo. That is, advising an obese diabetic patient to reduce their carb intake consistently produces better results than advising them to follow a low fat, calorie restricted diet.

The two diets:

Moderate carbohydrate diet: 45-50% carbs; 45 grams per meal + three 15 gram snacks = 165 grams per day; low fat, calorie restricted (500 Calorie deficit).  Otherwise known as a “low fat diet (LFD).”

In their words: “Active Comparator: American Diabetes Association Diet.  Participants in the American Diabetes Association (ADA) diet group will receive standard ADA advice. The diet includes high-fiber foods (such as vegetables, fruits, whole grains, and legumes), low-fat dairy products, fresh fish, and foods low in saturated fat.

Very low carbohydrate diet: Ketogenic; <50 grams of carb per day, no calorie restriction, just a goal of blood ketones 0.5 – 3 mM.

In their words: “Experimental: Low Carbohydrate Diet.  Participants will be instructed to follow a low carbohydrate diet: carbohydrate intake 10-50 grams a day not including fiber. Foods permitted include: meats, poultry, fish, eggs, cheese, cream, some nuts and seeds, green leafy vegetables, and most other non-starchy vegetables. Because most individuals self-limit caloric intake, no calorie restriction will be recommended.

Both groups were advised to maintain their usual protein intake.

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Circadian disruptions impact behavior and metabolism in a tissue-specific manner.

The control of circadian gene expression is complex, with layer upon layer of suppressors and enhancers, numerous transcription factors, and a lot of interactions.  A gross oversimplification: Clock and Bmal1 are positive regulators of circadian gene expression; Per and Cry are negative (you don’t really need to know any of this).

 

Some pretty cool progress has been made in examining the effects of global and tissue-specific deletion of circadian rhythm-related transcription factors.  Bear with me 🙂

For example, global Bmal1 knockout mice (ie, mice that don’t express Bmal1 anywhere in their whole body.  Zero Bmal1.  Nil.) (Lamia et al., 2008).  These mice are obese, and exhibit impaired glucose tolerance yet improved insulin sensitivity.

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Does junk food make you lazy?

From Times LIVE: “Does junk food make you lazy?” 

“A diet rich in processed foods and fat – and the extra weight that comes along with it – may actually cause fatigue, a lack of motivation and decreased performance, according to a recent study involving lab rats… excessive consumption of processed and fat-rich foods affects our motivation as well as our overall health.”

(this is categorically false as both diets used in the study being discussed were very low in fat.)

And from Psych Central: “Rat study shows junk food can make you lazy

The theory itself isn’t too far-fetched: a crap diet can cause weight gain and reduced energy expenditure, or a tendency to minimize any kind of physical activity… instead of: “’laziness’ causes obesity.”  And whether or not it’s true, unlike what some would have you believe, this wasn’t the study to prove it.

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Insulin, sympathetic nervous system, and nutrient timing.

Insulin secretion is attenuated by sympathetic nervous system activity; eg, via exercise.  Theoretically, exercising after a meal should blunt insulin secretion and I don’t think this will lessen the benefits of exercise, but rather enhance nutrient partitioning.   And this isn’t about the [mythical?] post-workout “anabolic window.”

Sympathetic innervation of pancreas: norepinephrine –> adrenergic receptor activation = decreased insulin secretion & increased lipolysis (Stich et al., 1999):

Stich insulin

Stich CAS

note how quickly catecholamines are cleared upon exercise cessation

Stich NEFA

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Insulin, dietary fat, and calories: context matters!

Jane Plain recently wrote a great article about the relationship between insulin, dietary fat, and calories.  There are a lot of data on this topic, which collectively suggest: context matters! 

For example,

Insulin and ketone responses to ingestion of MCTs and LCTs in man. (Pi-Sunyer et al., 1969)

14 healthy subjects, overnight fasted; dose: 1g/kg.

In brief, MCTs are more insulinogenic than corn oil.  But it’s not a lot of insulin.  Really.  Enough to inhibit lipolysis, perhaps, but that’s not saying much… & certainly not enough to induce hypoglycemia.

Pi-Sunyer MCT Corn oil

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