Thursday, October 29, 2015

New Post on Eat Move Sleep Blog

Yesterday, the Dan's Plan blog Eat Move Sleep published a blog post I wrote about sleep, artificial light, your brain, and a free computer program called f.lux that can help us live healthier lives.  Head over to Eat Move Sleep to read it.

Wednesday, October 28, 2015

The Brain Controls Insulin Action

Insulin regulates blood glucose primarily by two mechanisms:
  1. Suppressing glucose production by the liver
  2. Enhancing glucose uptake by other tissues, particularly muscle and liver
Since the cells contained in liver, muscle and other tissues respond directly to insulin stimulation, most people don't think about the role of the brain in this process.  An interesting paper just published in Diabetes reminds us of the central role of the brain in glucose metabolism as well as body fat regulation (1).  Investigators showed that by inhibiting insulin signaling in the brains of mice, they could diminish insulin's ability to suppress liver glucose production by 20%, and its ability to promote glucose uptake by muscle tissue by 59%.  In other words, the majority of insulin's ability to cause muscle to take up glucose is mediated by its effect on the brain. 

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Monday, October 26, 2015

Food Reward Fridays

Each Friday, I'm going to post a picture of a modern food so ridiculous it makes you want to laugh and cry at the same time.  I'm doing this for two reasons:
  1. To raise awareness about the unhealthy, fattening foods that are taking over global food culture.  These are highly rewarding, highly palatable, energy-dense foods that drive people to eat in the absence of hunger, and continue eating beyond calorie needs.  In many cases, the foods have been specifically designed to maximize "craveability" and palatability.
  2. Because it's funny.
Without further ado... the first lucky winner:
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Friday, October 23, 2015

Harvard Food Law Society "Forum on Food Policy" TEDx Conference

Last Friday, it was my pleasure to attended and present at the Harvard Food Law Society's TEDx conference, Forum on Food Policy.  I had never been to Cambridge or Boston before, and I was struck by how European they feel compared to Seattle.  The conference was a great success, thanks to the dedicated efforts of the Food Law Society's presidents Nate Rosenberg, Krista DeBoer, and many other volunteers. 

Dr. Robert Lustig gave a keynote address on Thursday evening, which I unfortunately wasn't able to attend due to my flight schedule.  From what I heard, he focused on practical solutions for reducing national sugar consumption, such as instituting a sugar tax.  Dr. Lustig was a major presence at the conference, and perhaps partially due to his efforts, sugar was a central focus throughout the day.  Nearly everyone agrees that added sugar is harmful to the nation's health at current intakes, so the question kept coming up "how long is it going to take us to do something about it?"  As Dr. David Ludwig said, "...the obesity epidemic can be viewed as a disease of technology with a simple, but politically difficult solution".

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Tuesday, October 20, 2015

Candy at the Cash Register

Last week, the New England Journal of Medicine published an interesting editorial titled "Candy at the Cash Register-- a Risk Factor for Obesity and Chronic Disease."  This fits in well with our discussion of non-homeostatic eating, or eating in the absence of calorie need.

There are a few quotes in this article that I find really perceptive.

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Saturday, October 17, 2015

Losing Fat With Simple Food-- Two Reader Anecdotes

Each week, I'm receiving more e-mails and comments from people who are successfully losing fat by eating simple (low reward) food, similar to what I described here.  In some cases, people are breaking through fat loss plateaus that they had reached on conventional low-carbohydrate, low-fat or paleo diets.  This concept can be applied to any type of diet, and I believe it is an important characteristic of ancestral food patterns.

At the Ancestral Health Symposium, I met two Whole Health Source readers, Aravind Balasubramanian and Kamal Patel, who were interested in trying a simple diet to lose fat and improve their health.  In addition, they wanted to break free of certain other high-reward activities in their lives that they felt were not constructive.  They recently embarked on an 8-week low-reward diet and lifestyle to test the effectiveness of the concepts.  Both of them had previously achieved a stable (in Aravind's case, reduced) weight on a paleo-ish diet prior to this experiment, but they still carried more fat than they wanted to.  They offered to write about their experience for WHS, and I thought other readers might find it informative.  Their story is below, followed by a few of my comments.

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Friday, October 9, 2015

Sleep and Genetic Obesity Risk

Evidence is steadily accumulating that insufficient sleep increases the risk of obesity and undermines fat loss efforts.  Short sleep duration is one of the most significant risk factors for obesity (1), and several potential mechanisms have been identified, including increased hunger, increased interest in calorie-dense highly palatable food, reduced drive to exercise, and alterations in hormones that influence appetite and body fatness.  Dan Pardi presented his research at AHS13 showing that sleep restriction reduces willpower to make healthy choices about food.

We also know that genetics has an outsized influence on obesity risk, accounting for about 70 percent of the variability in body fatness between people in affluent nations (2).  I have argued that "fat genes" don't directly lead to obesity, but they do determine who is susceptible to a fattening environment and who isn't (3).  I recently revisited a 2010 paper published in the journal Sleep by University of Washington researchers that supports this idea (4).

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Wednesday, October 7, 2015

The Case for the Food Reward Hypothesis of Obesity, Part II

In this post, I'll explore whether or not the scientific evidence is consistent with the predictions of the food reward hypothesis, as outlined in the last post.

Before diving in, I'd like to address the critique that the food reward concept is a tautology or relies on circular reasoning (or is not testable/falsifiable).  This critique has no logical basis.  The reward and palatability value of a food is not defined by its effect on energy intake or body fatness.  In the research setting, food reward is measured by the ability of food or food-related stimuli to reinforce or motivate behavior (e.g., 1).  In humans, palatability is measured by having a person taste a food and rate its pleasantness in a standardized, quantifiable manner, or sometimes by looking at brain activity by fMRI or related techniques (2).  In rodents, it is measured by observing stereotyped facial responses to palatable and unpalatable foods, which are similar to those seen in human infants.  It is not a tautology or circular reasoning to say that the reinforcing value or pleasantness of food influences food intake and body fatness. These are quantifiable concepts and as I will explain, their relationship with food intake and body fatness can be, and already has been, tested in a controlled manner. 

1.   Increasing the reward/palatability value of the diet should cause fat gain in animals and humans

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Sunday, October 4, 2015

Photos and More Gardening

I've needed new professional and blog photos for a long time.  My friend Adam Roe was in town recently, and he happens to be professional photographer, so he graciously offered to snap a few shots.  Despite less than ideal conditions, he did an outstanding job.  Here's a larger version of the photo on my profile (which Blogger shrinks down to a tiny thumbnail):


To see more of Adam's work, head over to his Facebook page, and don't forget to 'like' and share it if you enjoy it.  Adam is currently based in Berlin.

Gardening Update

Here's a photo of today's harvest (taken by me, not Adam; you can tell by the poor focus and primitive lighting):

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Thursday, October 1, 2015

The Case for the Food Reward Hypothesis of Obesity, Part I

Introduction

When you want to investigate something using the scientific method, first you create a model that you hope describes a natural phenomenon-- this is called a hypothesis.  Then you go about testing that model against reality, under controlled conditions, to see if it has any predictive power.  There is rarely a single experiment, or single study, that can demonstrate that a hypothesis is correct.  Most important hypotheses require many mutually buttressing lines of evidence from multiple research groups before they're widely accepted.  Although it's not necessary, understanding the mechanism by which an effect occurs, and having that mechanism be consistent with the hypothesis, adds substantially to the case.

With that in mind, this post will go into greater detail on the evidence supporting food reward and palatability as major factors in the regulation of food intake and body fatness.  There is a large amount of supportive evidence at this point, which is rapidly expanding due to the efforts of many brilliant researchers, however for the sake of clarity and brevity, so far I've only given a "tip of the iceberg" view of it.  But there are two types of people who want more detail: (1) the skeptics, and (2) scientifically inclined people who want mechanism.  This post is for them.  It will get technical at times, as there is no other way to convey the material effectively.

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