The Genetics of Obesity, Part III

Genetics Loads the Gun, Environment Pulls the Trigger

Thanks to a WHS reader* for reminding me of the above quote by Dr. Francis Collins, director of the US National Institutes of Health**.  This is a concept that helps reconcile the following two seemingly contradictory observations:

1. Roughly 70 percent of obesity risk is genetically inherited, leaving only 30 percent of risk to environmental factors such as diet and lifestyle.
2. Diet and lifestyle have a large impact on obesity risk.  The prevalence of obesity has tripled in the last 30 years, and the prevalence of extreme obesity has increased by almost 10-fold.  This is presumably not enough time for genetic changes to account for it.

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Return to the Source Parkour Camp

For those who are interested in natural movement training, this summer my friend Rafe Kelley will be hosting an interesting three-day event near Bellingham, WA called "Return to the Source".  Rafe is skilled in a variety of movement disciplines and is the co-founder of the Seattle parkour gym Parkour Visions.  Parkour is a very fun sport that hones our natural ability to skillfully navigate physical obstacles, but it's usually done in an urban context.

The camp will take place from August 23-25.  Here's a description from the Parkour Visions site:

"This summer, return to the source of human movement with Parkour Visions as we explore the natural environment in and around Bellingham, WA. Rafe Kelley will introduce you to the benefits of training and playing in nature. You will learn how to adapt your technique and movement to moving effectively through woods, over rocks, and in trees during this unique, 3-day experience."

Watch this video if you want to see what you're in for.

Knowing Rafe, it will be fun and productive.  You can sign up through this page (scroll down).

The Genetics of Obesity, Part II

Rodents Lead the Way

The study of obesity genetics dates back more than half a century.  In 1949, researchers at the Jackson Laboratories identified a remarkably fat mouse, which they determined carried a spontaneous mutation in an unidentified gene.  They named this the "obese" (ob/ob) mouse.  Over the next few decades, researchers identified several other genetically obese mice with spontaneous mutations, including diabetic (db/db) mice, "agouti" (Avy) mice, and "Zucker" (fa/fa) rats.

At the time of discovery, no one knew where the mutations resided in the genome.  All they knew is that the mutations were in single genes, and they resulted in extreme obesity.  Researchers recognized this as a huge opportunity to learn something important about the regulation of body fatness in an unbiased way.  Unbiased because these mutations could be identified with no prior knowledge about their function, therefore the investigators' pre-existing beliefs about the mechanisms of body fat regulation could have no impact on what they learned.  Many different research groups tried to pin down the underlying source of dysfunction: some thought it was elevated insulin and changes in adipose tissue metabolism, others thought it was elevated cortisol, and a variety of other hypotheses.

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Food Reward Friday

This week's lucky "winner"... beer!!

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The Genetics of Obesity, Part I

Choosing the Right Parents: the Best Way to Stay Lean?

In 1990, Dr. Claude Bouchard and colleagues published a simple but fascinating study demonstrating the importance of genetics in body fatness (1).  They took advantage of one of the most useful tools in human genetics: identical twins.  This is what happens when a single fertilized egg generates two embryos in utero and two genetically identical humans are born from the same womb.   By comparing identical twins to other people who are not genetically identical (e.g., non-identical twins), we can quantify the impact of genes vs. environment on individual characteristics (2).

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Food Reward Friday

This week's lucky "winner"... low-carb gluten-free bacon chocolate mocha ice cream cake!!

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Food Reward Friday

This week's lucky "winner"... cronuts!!

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Food Reward Friday

This week's "winner" will certainly be the most controversial yet... bacon!!

Bacon is a fatty cut of pork (typically side or back) that has been thinly sliced, cured, then cooked until crispy.  This results in a fatty, salty, savory flavor that almost everyone loves.  Bacon's extremely high calorie density, saltiness, and savory flavor give it a reward value that competes with chocolate and ice cream.  Sometimes it's even used to flavor chocolate and ice cream!

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Update

I haven't been putting much effort into blogging these past few weeks.  Frankly, a little break has been nice while I take care of other things in my life.  But I haven't been twiddling my thumbs.  Obesity research hasn't slowed down and there are many topics that I'd love to write about here if I had the time.  I'll be starting a new series soon on the genetics of obesity-- a fascinating subject.  I also plan to cover some of my recent publications on obesity and blood glucose control by the brain.  Last but not least, we will soon roll out a substantially upgraded version of the Ideal Weight Program.  Those who have already purchased the program will continue to have access to the new version.

Cara Mencegah Kanker Payudara

Cara Mencegah Kanker Payudara - Pada artikel sebelumnya telah dibahas tentang apa itu kanker payudara, penyebab kanker payudara, dan gejala kanker payudara. Kali ini akan saya bahas tentang cara mencegah kanker payudara.

Adapun cara-cara untuk mencegah kanker payudara sebagai berikut :


Hindari penggunaan BH yang terlalu ketat dalam waktu lama.
Hindari banyak merokok dan mengkonsumsi alkohol.

Gejala - Gejala Kanker Payudara

Gejala Kanker Payudara - Kanker Payudara merupakan penyakit yang paling ditakuti wanita, penyakit yang satu ini merupakan penyakit ganas yang seringkali berujung kematian.

Penyakit kanker payudara terbilang penyakit kangker yang paling umum menyerang kaum wanita, meski demikian pria pun memiliki kemungkinan mengalami penyakit ini dengan perbandingan 1 di antara 1000.

Beberapa faktor risiko

Mengenal Penyakit Kanker Payudara

Kanker Payudara

Kanker payudara merupakan jenis penyakit kanker dengan jumlah penderita terbanyak nomor dua di dunia. Sedangkan dari tingkat kematian, kanker payudara menyebabkan kematian nomor lima terbesar di dunia.

Beberapa tahun lalu, kanker payudara di Indonesia berada di urutan kedua tertinggi setelah kanker serviks. Namun, sekarang kanker payudara malah menduduki peringkat pertama

Manfaat - Manfaat Pisang Bagi Kesehatan

Manfaat Pisang

Manfaat Pisang - Pisang adalah salah satu buah populer yang banyak dijuampai di pedesaan maupun perkotaan. Pisang kaya akan serat dan mengandung 3 jenis gula alami yakni glukosa, sukrosa, dan fruktosa, yang membuat pisang memiliki berbagai manfaat. Apa saja manfaat pisang bagi kesehatan? Berikut ulasannya:

1. Sebagai Sumber Tenaga.
Kandungan Gula dalam pisang dengan mudah dapat

Cara Menghilangkan Panu

Cara Menghilangkan Panu

Cara Menghilangkan Panu - Panu atau dalam istilah medis "Pitriyasis Versicolor" merupakan salah satu penyakit kulit yang disebabkan oleh infeksi jamur Pityrosporum ovale di permukaan kulit.

Panu adalah penyakit kulit yang sebenarnya tidak mematikan namun keberadaan panu pada kulit apalagi bila panu tersebut berada disekitar wajah anda tentunya akan mengakibatkan

The Neurobiology of the Obesity Epidemic

I recently read an interesting review paper by Dr. Edmund T. Rolls titled "Taste, olfactory and food texture reward processing in the brain and the control of appetite" that I'll discuss in this post (1).  Dr. Rolls is a prolific neuroscience researcher at Oxford who focuses on "the brain mechanisms of perception, memory, emotion and feeding, and thus of perceptual, memory, emotional and appetite disorders."  His website is here.

The first half of the paper is technical and discusses some of Dr. Rolls' findings on how specific brain areas process sensory and reward information, and how individual neurons can integrate multiple sensory signals during this process.  I recommend reading it if you have the background and interest, but I'm not going to cover it here.  The second half of the paper is an attempt to explain the obesity epidemic based on what he knows about the brain and other aspects of human biology.

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Cara Menghilangkan Stres

Cara Menghilangkan Stres - Stres adalah suatu kondisi yang terjadi dikarenakan tekanan yang melebihi kemampuan maksimum seseorang secara psikologis sehingga tindakannya menjadi kurang terkontrol secara sehat serta terganggunya sistem metabolisme tubuh sehingga menimbulkan berbagai macam penyakit.

Stres banyak dialami oleh masyarakat perkotaan saat ini di seluruh dunia, karena dipengaruhi oleh

Jerawat Pada Kemaluan Pria, Bahayakah?

Jerawat Pada Kemaluan - Bagi pria, punya jerawat terkadang memalukan, apalagi munculnya bukan cuma di wajah tetapi juga di kemaluan.

Jerawat pada kemaluan pria ada banyak pemicunya, sebagian berbahaya dan sebagian lagi dianggap normal. Bagaimana membedakannya?

Benjolan seperti jerawat yang muncul dikemaluan sangat beragam. Bisa saja benjolan tersebut adalah abses biasa atau bisa juga kista

Inilah Makanan-Makanan Penyebab Ketombe

Makanan Penyebab Ketombe - Tak hanya gaya hidup yang memicu munculnya ketombe, namun juga makanan yang kita konsumsi. Berikut ini beberapa makanan yang dapat menimbulkan ketombe, bahkan memperparah ketombe.

1. Makanan Produk Susu.
Susu dan turunannya mengurangi ketahanan kondisi kulit kepala dan memicu munculnya ketombe.

2. Gorengan.
Makanan yang digoreng (gorengan) merangsang minyak

8 Cara Mudah Membuat Gigi Putih dan Sehat

Cara Memutihkan Gigi - Memiliki gigi putih membuat senyum akan semakin menawan. Namun gigi ternyata tidak cukup putih, tetapi juga harus sehat. Jadi coba simak cara membuat gigi putih dan sehat berikut ini.

1. Makanan dan Minuman.
Setelah minum teh, kopi, soda, atau merokok, segera bersihkan gigi atau makan apel demi mencegah noda yang tertinggal. Selain itu, jangan malas makan buah-buahan

Cara Mengatasi Ngantuk Berlebihan

Cara Mengatasi Ngantuk - Pada artikel sebelumnya telah dibahas penyebab-penyebab selalu mengantuk sepanjang hari, yang menandakan adanya penyakit.

Untuk mengatasi rasa ngantuk yang selalu datang sepanjang hari, berikut tips yang bisa anda lakukan.

1. Konsumsi Kacang Almond.
Kacang almond kaya akan zat besi yang dapat meningkatkan aliran darah dalam tubuh.

2. Banyak minum Air Putih.
Selain

Speaking at AHS13

The 2013 Ancestral Health Symposium will be held in Atlanta, GA, August 14-17.  Last year was a great conference, and I look forward to more informative talks and networking.  Tickets go fast, so reserve yours now if you plan to attend!

This year, I'll be speaking on insulin and obesity.  My talk will be titled "Insulin and Obesity: Reconciling Conflicting Evidence".  In this talk, I'll present the evidence for and against the idea that elevated insulin contributes to the development of obesity.  One hypothesis states that elevated insulin contributes to obesity, while the other states that elevated insulin is caused by obesity and does not contribute to it.  Both sides of the debate present evidence that appears compelling, and it often seems like each side is talking past the other rather than trying to incorporate all of the evidence into a larger, more powerful model.

There's a lot evidence that can be brought to bear on this question, but much of it hasn't reached the public yet.  I'll explore a broad swath of evidence from clinical case studies, observational studies, controlled trials, animal research, physiology, and cell biology to test the two competing hypotheses and outline a model that can explain all of the seemingly conflicting data.  Much of this information hasn't appeared on this blog.  My goal is to put together a talk that will be informative to a researcher but also accessible to an informed layperson.

On a separate note, my AHS12 talk "Digestive Health, Inflammation and the Metabolic Syndrome" has not been posted online because the video recording of my talk has mysteriously disappeared.  I think many WHS readers would be interested in the talk, since it covers research on the important and interdependent influence of gut health, inflammation, and psychological stress on the metabolic syndrome (the quintessential modern metabolic disorder).  I'm going to try to find time to make a narrated slideshow so I can post it on YouTube.

Penyebab Selalu Ngantuk Berlebihan Sepanjang Hari

Penyebab Ngantuk - Jika Anda sudah tidur berjam-jam, tapi masih terasa ngantuk, maka Anda perlu mewaspadai adanya penyakit di dalam tubuh.

Berikut beberapa penyebab yang membuat orang selalu mengantuk sepanjang hari.

1. Anemia.
Anemia merupakan penyebab utama rasa kantuk sering datang.
Kekurangan darah menyebabkan kurangnya zat besi, sel darah merah yang diperlukan untuk membawa oksigen ke

Gejala-Gejala Penyakit Diabetes

Gejala Diabetes - Diabetes bisa menyerang orang dari segala usia. Bahkan dengan gejala-gejala yang mungkin tidak pernah disadari penderitanya.

Diabetes dapat terjadi akibat tingginya kadar gula darah.

Menurut sebuah survey, sekitar satu dari tiga orang dengan diabetes tipe 2 tidak tahu mereka mengalami penyakit tersebut.

Berikut beberapa gejala diabetes yang jarang diperhatikan oleh para

Manfaat Sarapan Pagi Bagi Kesehatan

Manfaat Sarapan - Menunda sarapan membuat Anda sulit memperoleh asupan nutrisi dan vitamin yang direkomendasikan.

Menu sarapan seperti sereal dengan susu atau yogurt rendah lemak plus akan memberi cukup kalsium dan serat.

Apa saja manfaat sarapan pagi bagi kesehatan? Cekidot ;)

1. Sarapan Tingkatkan Kemampuan Otak.
Riset para ahli membuktikan bahwa pelajar yang selalu sarapan mencatat

Manfaat-Manfaat Tidur Siang

Manfaat Tidur Siang - Sering malas tidur siang? Atau tidak ada waktu untuk tidur siang? Pikirkan lagi. Karena tidur siang punya banyak manfaat. Apa saja?

Tidur merupakan salah satu solusi yang paling baik untuk mengistirahatkan tubuh setelah seharian beraktifitas, ini jelas lebih baik daripada hanya sekedar mengkonsumsi vitamin suplemen untuk mendongkrak supaya tubuh kita selalu fit. Namun,

Food Variety, Calorie Intake, and Weight Gain

Let's kick off this post with a quote from a 2001 review paper (1):

Increased variety in the food supply may contribute to the development and maintenance of obesity.  Thirty-nine studies examining dietary variety, energy intake, and body composition are reviewed. Animal and human studies show that food consumption increases when there is more variety in a meal or diet and that greater dietary variety is associated with increased body weight and fat.

This may seem counterintuitive, since variety in the diet is generally seen as a good thing.  In some ways, it is a good thing, however in this post we'll see that it can have a downside.
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Food Reward Friday

This week's lucky "winner"... ice cream!!

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Book Review: Salt, Sugar, Fat

Michael Moss is a Pulitzer prize-winning journalist who has made a career writing about the US food system.  In his latest book, Salt, Sugar, Fat: How the Food Giants Hooked Us, he attempts to explain how the processed food industry has been so successful at increasing its control over US "stomach share".  Although the book doesn't focus on the obesity epidemic, the relevance is obvious.  Salt, Sugar, Fat is required reading for anyone who wants to understand why obesity is becoming more common in the US and throughout the world.

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Food Reward Friday

This week's lucky "winner"... energy bars!

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Cara Mengecilkan Paha

Memiliki paha dan betis yang ramping selalu menjadi idaman kaum hawa. Paha yang kecil (ramping) akan terlihat sexy jika menggunakan celana pendek. Lain halnya dengan bentuk paha yang besar dan tertimbun lemak ;). Nah, untuk melengkapi artikel tips kecantikan pada blog ini, kali ini saya akan mengulas tentang cara mengecilkan paha, yang bisa anda lakukan dirumah.



Pada dasarnya artikel ini

Glucagon, Dietary Protein, and Low-Carbohydrate Diets

Glucagon is a hormone that plays an important role in blood glucose control.  Like insulin, it's secreted by the pancreas, though it's secreted by a different cell population than insulin (alpha vs. beta cells).  In some ways, glucagon opposes insulin.  However, the role of glucagon in metabolism is frequently misunderstood in diet-health circles.

The liver normally stores glucose in the form of glycogen and releases it into the bloodstream as needed.  It can also manufacture glucose from glycerol, lactate, and certain amino acids.  Glucagon's main job is to keep blood glucose from dipping too low by making sure the liver releases enough glucose.  There are a few situations where this is particularly important:

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Are Animal Crackers Paleo?

Every child loves animal crackers, those sweet and crunchy animal-shaped biscuits.  But are they compatible with a Paleo diet?  Some people might think they already know the answer, but consider this: our ancestors evolved on the African savanna, eating the plants and animals found there.  Inside each box of animal crackers is an assortment of tiny savanna creatures such as giraffes and elephants.

To get to the bottom of this, I interviewed Robert Pearson, CEO of Animal Cracker Products Inc., who explained to me how these crackers are made.

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Cara Mengecilkan Betis

Memiliki kaki yang jenjang, dengan betis dan paha yang ramping selalu menjadi idaman para wanita. Apalagi dengan semakin populernya rok dan celana pendek yang otomatis mempertontonkan paha dan betis yang kecil. Ukuran betis yang tidak ideal bisa dikarenakan timbunan lemak pada bagian tersebut atau karena memang otot betis yang sudah mulai mengendur. Selain itu juga disebabkan faktor keturunan

Food Reward Friday

This week's "lucky" winner... milkshakes!

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Neuronal Control of Appetite, Metabolism and Weight

Last week, I attended a Keystone conference, "Neuronal Control of Appetite, Metabolism and Weight", in Banff.  Keystone conferences are small, focused meetings that tend to attract high quality science.  This particular conference centered around my own professional research interests, and it was incredibly informative.  This post is a summary of some of the most salient points.

Rapid Pace of Scientific Progress

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Food Reward Friday

This week's luck winner(s)... pastries!!

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Food Reward Friday

This week's lucky "winner"... fried Coke!

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Atherosclerosis in Ancient Mummies Revisited

Many of you are already aware of the recent study that examined atherosclerosis in 137 ancient mummies from four different cultures (1).  Investigators used computed tomography (CT; a form of X-ray) to examine artery calcification in mummies from ancient Egypt, Peru, Puebloans, and arctic Unangan hunter-gatherers.  Artery calcification is the accumulation of calcium in the vessel wall, and it is a marker of severe atherosclerosis.  Where there is calcification, the artery wall is thickened and extensively damaged.  Not surprisingly, this is a risk factor for heart attack.  Pockets of calcification are typical as people age.

I'm not going to re-hash the paper in detail because that has been done elsewhere.  However, I do want to make a few key points about the study and its interpretation.  First, all groups had atherosclerosis to a similar degree, and it increased with advancing age.  This suggests that atherosclerosis may be part of the human condition, and not a modern disease.  Although it's interesting to have this confirmed in ancient mummies, we already knew this from cardiac autopsy data in a variety of non-industrial cultures (2, 3, 4, 5).

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Food Reward Friday

This week's lucky "winner"... Yoplait Go-Gurt!

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Does the Mediterranean Diet Reduce Cardiovascular Risk?

By now, most of you have probably heard about the recent study on the "Mediterranean diet" (1), a diet that was designed by diet-heart researchers and is based loosely on the traditional diet of Crete and certain other Mediterranean regions.  The popular press has been enthusiastically reporting this trial as long-awaited proof that the Mediterranean diet reduces the risk of cardiovascular events-- by a full 30 percent over a 4.8-year period.  I wish I could share their enthusiasm for the study.

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Your Brain on Potato Chips

Or, more accurately, a rat's brain on potato chips.  Last week, PLoS One published a very interesting paper by Dr. Tobias Hoch and colleagues on what happens in a rat's brain when it is exposed to a highly palatable/rewarding food (1).  Rats, like humans, overconsume highly palatable foods even when they're sated on less palatable foods (2), and feeding rats a variety of palatable human junk foods is one of the most effective ways to fatten them (3).  Since the brain directs all behaviors, food consumption is an expression of brain activity patterns.  So what is the brain activity pattern that leads to the overconsumption of a highly palatable and rewarding food?

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Salt Sugar Fat

I'd just like to put in a quick word for a book that will be released tomorrow, titled Salt Sugar Fat: How the Food Giants Hooked Us, by Pulitzer prize-winning author Michael Moss.  This is along the same lines as Dr. David Kessler's book The End of Overeating, which explains how the food industry uses food reward, palatability, and food cues to maximize sales-- and as an unintended side effect, maximize our waistlines.   Judging by Moss's recent article in New York Times Magazine, which I highly recommend reading, the book will be excellent.  I've pre-ordered it.

Food Reward Friday

This week, Food Reward Friday is going to be a little bit different.  I've received a few e-mails from people who would like to see me write about some of the less obvious examples of food reward-- foods that are less extreme, but much more common, and that nevertheless promote overeating.  Let's face it, even though they're funny and they (sometimes) illustrate the principle, most people reading this blog don't eat banana splits very often, much less pizzas made out of hot dogs.

So this week's "winner" is something many of you have in your houses right now, and which was also the subject of an interesting recent study... potato chips!

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Body Fatness and Cardiovascular Risk Factors

I recently revisited a really cool paper published in the Lancet in 2009 on body fatness, biomarkers, health, and mortality (1). It's a meta-analysis that compiled body mass index (BMI) data from nearly 900,000 individual people, and related it to circulating lipids and various health outcomes.  This is one of the most authoritative papers on the subject.

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Food Reward Friday

This week's "winner"... the Banana Split!

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Food Reward Friday

This week's lucky "winner"... an unnamed hot dog-laden Pizza Hut monstrosity with tempura shrimp and mayonnaise!

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Why Do We Eat? A Neurobiological Perspective. Part VIII

In the (probably) last post of this series, I'll take the pieces that I've gradually outlined in previous posts, and put them together into a big-picture, common-sense framework for thinking about human eating behavior, and why we eat more today than ever before.

Why is Eating Behavior Regulated?

Let's start at the most fundamental level.  To be competitive in a natural environment, organisms must find rational ways of interacting with their surroundings to promote survival and reproduction.  One of the most important elements of survival is the acquisition of energy and chemical building blocks, either by photosynthesis, or (in the case of animals) eating other organisms.  This imperative drove the evolution of rational food seeking behaviors long before the emergence of humans, mammals, reptiles, amphibians, fish, worms, and even eukaryotes (organisms with nuclei).

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Why Do We Eat? A Neurobiological Perspective. Part VII

Welcome back to the series, after a bit of a hiatus!  In previous posts, we covered the fact that humans eat because we're motivated to eat, and many things can motivate us to eat.  These include factors related to energy need (homeostatic factors), such as hunger, and factors that have little to do with energy need or hunger (non-homeostatic factors).  These many factors are all processed in specialized brain 'modules' that ultimately converge on a central action selection system (part of the reward system); this is the part of you that decides whether or not to initiate eating behaviors.

This will be somewhat of a catch-all post in which I discuss cognitive, emotional, and habit influences on food intake.  Since these factors are not my specialty, I'll keep it brief, but I don't mean to suggest they aren't important.

Food 'Cost'

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Why Do We Eat? A Neurobiological Perspective. Part VI

In previous posts in this series, I explained that the brain (primarily the mesolimbic system) integrates various factors to decide whether or not to drive food seeking and consumption behaviors.  These include homeostatic factors such as hunger, and non-homeostatic factors such as palatability and the social environment.

In this post, I'll examine the reward system more closely.  This is the system that governs the motivation for food, and behavioral reinforcement (a form of learning).  It does this by receiving information from other parts of the brain that it uses to determine if it's appropriate to drive (motivate) food seeking behavior.  I covered its role in motivation in the first post of the series, so in this post I'll address reinforcement.

Behavioral Reinforcement

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Why Do We Eat? A Neurobiological Perspective. Part V

In previous posts, I explained that food intake is determined by a variety of factors that are detected by the brain, and integrated by circuits in the mesolimbic system to determine the overall motivation to eat.  These factors include 'homeostatic factors' that reflect a true energy need by the body, and 'non-homeostatic factors' that are independent of the body's energy needs (e.g. palatability, habit, and the social environment).

In this post, we'll explore the hedonic system, which governs pleasure.  This includes the pleasure associated with food, called palatability.  The palatability of food is one of the factors that determines food intake.

The Hedonic System

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Why Do We Eat? A Neurobiological Perspective. Part IV

In this post, I'll follow up on the last post with a discussion two more important factors that can affect energy homeostasis and therefore our food intake and propensity to gain fat: age and menopause.

Age

Although it often isn't the case in non-industrial cultures, in affluent nations most people gain fat with age.  This fat gain continues until old age, when many people once again lose fat.  This is probably related to a number of factors, three of which I'll discuss.  The first is that we tend to become less physically active with age.  The second, related factor is that we lose lean mass with age, and so energy expenditure declines.

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Why Do We Eat? A Neurobiological Perspective. Part III

In the first post, I explained that all voluntary actions are driven by a central action selection system in the mesolimbic area (the reward system).  This is the part of you that makes the decision to act, or not to act.  This system determines your overall motivation to obtain food, based on a variety of internal and external factors, for example hunger, the effort required to obtain food, and the sensory qualities of food/drink.  These factors are recognized and processed by a number of specialized 'modules' in the brain, and forwarded to the reward system where the decision to eat, or not to eat, is made.  Researchers divide food intake into two categories: 1) eating from a true energy need by the body (homeostatic eating), e.g. hunger, and 2) eating for other reasons (non-homeostatic eating), e.g. eating for social reasons or because the food tastes really good.

In the second post of the series, we explored how the brain regulates food intake on a meal-to meal basis based on feedback from the digestive system, and how food properties can influence this process.  The integrated gut-brain system that accomplishes this can be called the satiety system.

In this post, we'll explore the energy homeostasis system, which regulates energy balance (energy in vs. energy out) and body fatness on a long term basis.

The Energy Homeostasis System

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Why Do We Eat? A Neurobiological Perspective. Part II

In the last post, I explained that eating behavior is determined by a variety of factors, including hunger and a number of others that I'll gradually explore as we make our way through the series.  These factors are recognized by specialized brain 'modules' and forwarded to a central action selection system in the mesolimbic area (the reward system), which determines if they are collectively sufficient cause for action.  If so, they're forwarded to brain systems that directly drive the physical movements involved in seeking and consuming food (motor systems).

The term 'homeostasis' is important in biology.  Homeostasis is a process that attempts to keep a particular factor within a certain stable range.  The thermostat in your house is an example of a homeostatic system.  It reacts to upward or downward changes in a manner that keeps temperature in a comfortable range.  The human body also contains a thermostat that keeps internal temperature close to 98.6 F.  Many things are homeostatically regulated by the body, and one of them is energy status (how much energy the body has available for use).  Homeostasis of large-scale processes in the body is typically regulated by the brain.

We can divide the factors that determine feeding behavior into two categories, homeostatic and non-homeostatic.  Homeostatic eating is when food intake is driven by a true energy need, as perceived by the brain.  For the most part, this is eating in response to hunger.  Non-homeostatic eating is when food intake is driven by factors other than energy need, such as palatability, habitual meal time, and food cues (e.g. you just walked by a vending machine full of Flamin' Hot Cheetos).

We can divide energy homeostasis into two sub-categories: 1) the system that regulates short-term, meal-to-meal calorie intake, and 2) the system that regulates fat mass, the long-term energy reserve of the human body.  In this post, I'll give an overview of the process that regulates energy homeostasis on a short-term, meal-to-meal basis.

The Satiety System (Short-Term Energy Homeostasis)


The stomach of an adult human has a capacity of 2-4 liters.  In practice, people rarely eat that volume of food.  In fact, most of us feel completely stuffed long before we've reached full stomach capacity.  Why?

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Why Do We Eat? A Neurobiological Perspective. Part I

As with all voluntary movements, eating food is an expression of activity in the brain.  The brain integrates various inputs from around the body, and outside the body, and decides whether or not to execute the goal-directed behaviors of food seeking and consumption.  Research has uncovered a lot about how this process works, and in this series I'll give a simplified overview of what scientists have learned about how, and why, the brain decides to eat.

The Gatekeeper of Voluntary Behaviors

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Comment Policy

Over the last year, I've noticed that the quality of the comments section here has deteriorated significantly, with a high proportion of poorly grounded and/or disrespectful comments, typically from anonymous or semi-anonymous people.  This is the nature of the Internet I suppose-- comments sections are rowdy places.  But ultimately I do have control over this, and I intend to exert it to maintain a higher level of information quality and decorum in my corner of the Internet.

For the foreseeable future, I'll be moderating comments.  Here are my criteria for deciding whether or not a comment will be published:

1. Value.  Comments should be well thought out, and points supported by research or at least solid logic.  Personal anecdotes are welcome as long as they aren't over-interpreted.  Thoughtful questions are also welcome, although I can't guarantee I'll answer them.  As always, anyone is free to disagree with me in a constructive manner, or simply offer a word of support.  
2. Respect.  Comments should be respectful to me and other commenters, and composed in a concise manner.  It isn't difficult to disagree in a respectful way.
3. On topic.  Comments should be at least somewhat relevant to the subject of the post.
4. Full name.  Attaching your full name to a comment means taking responsibility for what you write.  I'll continue to publish anonymous comments if they add value, but I'll be more likely to publish if you include your full name in your screen name, your profile, or at the bottom of your comment.
5. No ads.  I will not publish links to commercial sites that do not add value to the discussion, nor will I publish any other link I find objectionable.

Because I'll be moderating, I've decided to remove the captcha word authentication, which many people found difficult to use.  We'll see how that goes.  Since I have a lot on my plate, and Whole Health Source is a one-man show, I may not always moderate comments in a timely manner.  I apologize in advance for the inconvenience.  

Announcing the Ideal Weight Program

I often receive requests from people asking for my overall perspective on fat loss and health.  I share my opinions here, but they're scattered throughout hundreds of posts, there's a lot I haven't had a chance to write about, and I rarely give practical recommendations.  However, I knew I'd eventually put everything together into a cohesive fat loss program-- it was only a matter of finding the right opportunity.

That opportunity presented itself in 2011 when I met Dan Pardi, a researcher whose work focuses on sleep and food intake, and the CEO of a company called Dan's Plan.  I was immediately impressed by Dan because he stood out as someone with a high level of expertise in sleep and physical activity, as well as someone who has successfully lost a substantial amount of fat and kept it off for several years.

Dan and his team had developed a set of unique and engaging tools for tracking weight, sleep, and physical activity to help people maintain daily mindfulness over the simple fundamentals of health.  These tools are 100 percent free and incredibly easy to use, particularly if you sync them with an electronic scale and step counter.  When synced with these devices, the Dan's Plan website automatically uploads and displays your weight, sleep, and physical activity score, as well as integrating them all into a single user-friendly Health Zone Score that lets you know your overall performance at a glance.  Even if you have no interest in fat loss, I highly recommend using the free tracking tools on the Dan's Plan site-- I do.

In early 2012, Dan approached me about creating a fat loss program for Dan's Plan that incorporates their unique tracking tools.  This struck me as an excellent opportunity to create a diet and lifestyle program that combines sound science with exciting new technology.  Dan and I both brought science to the table, and Dan also brought the perspective gained from working with others to help them lose fat, as well as his own successful fat loss experience.  Dan and I have been working hard on this project, and we're finally ready to launch.

I'm happy to announce the Ideal Weight Program, an effective new system for fat loss and maintenance.

What is the Ideal Weight Program?

The Ideal Weight Program is a unique system for fat loss and maintenance that draws from the latest science on diet, physical activity, sleep, and behavior modification, and pairs it with engaging tools that help you define your goals and meet them.  It keeps you consistently focused on the everyday factors that really matter for fat loss, and gives you the skills you need to make sustainable diet and lifestyle changes.  Based on your own goals and priorities, you can choose one of two diet strategies for the initial fat loss phase:

• The Fat Loss and Sustainable Health (FLASH) diet, an intensive high-protein diet for rapid fat loss.
• The Simple Food Diet, a more flexible diet based on whole, natural foods specifically selected for fat loss.  One important goal of this diet is to teach healthy cooking skills, using recipes and tips provided.

These diets are designed to naturally promote a lower calorie intake and fat loss, without requiring calorie counting.  The Ideal Weight Program also includes important physical activity and sleep components, and explains why these are so critical for fat loss and health.  Dan and I discussed some of the principles underlying the Ideal Weight Program on Chris Kresser's podcast recently.

Here's what you get when you sign up:

• Detailed documents that walk you through the program
• Weight, sleep, and physical activity tracking tools tailored for fat loss
• Simple recipes and cooking tips that work with almost anything in your fridge
• Videos that explain the key concepts behind fat loss and maintenance
• An e-book explaining the scientific rationale behind the program

Signing up for the Ideal Weight Program gives you lifetime access to everything.  We've discounted the initial price, because we want to hear your feedback so that we can continue to improve the program over time.  If you follow the link below, first you'll be prompted to sign up for a basic Dan's Plan account, and once you have your account set up, you'll be able to purchase the Ideal Weight Program:

Ideal Weight Program



Financial disclosure: I will receive a portion of the revenue from the sale of the Ideal Weight Program.  I do not receive revenue from the sale of other products associated with Dan's Plan or the Ideal Weight Program (such as the Fitbit, cooking tools, and other programs).

Food Reward Friday

This week's "winner"... the KFC Double Down sandwich!

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Comment Published in Nature

I recently read an opinion piece by Gary Taubes in the scientific journal Nature, titled "Treat Obesity as Physiology, not Physics", in which he promoted NuSI and repeated the statement that obesity research is a "house of cards" because it focuses on calories in/out, at the expense of studying the "hormonal regulatory disorders" underlying obesity (1).  I wrote a letter to the editor in response to Taubes's commentary, which has been published in Nature (2).

I'm used to seeing these kinds of claims in the popular press at this point, but to see it published in a scientific journal is galling (even if it's in the opinion section).  This is the equivalent of a person who has never held an ax telling a group of lumberjacks they need to focus on cutting trees.  It's part of a disturbing trend of popular writers in the low-carb and Paleo world attacking researchers, and even entire fields of research, they have little understanding of.  Of course this only applies to a minority of the community, but this argumentation style smells of desperation and reflects poorly on the community as a whole.

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Dogs Eating Carbs

Five years ago, I had an interesting conversation with a veterinarian friend about dog food.  We were talking about diabetes in one of the dogs she was treating, and I remarked "that's what happens when you feed a carnivore carbohydrate".  She gave me a funny look.  At the time, I was seeing the world through the low-carb lens, and I remember thinking how bizarre it was that she didn't yield to my impeccable logic.  As they say, live and learn.

The journal Nature published a fascinating paper on the evolution of the domestic dog today (1).  Researchers compared the genome of wolves and domestic dogs to see what genetic changes accompanied domestication.

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Food Reward Friday

This week's "winner"... the Garbage Plate!!

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Appearance on "Ask the Low-Carb Experts" Podcast Postponed

I was scheduled to appear on Jimmy Moore's show "Ask the Low-Carb Experts" this Thursday.  I don't consider myself a low-carb expert, but I do have expertise in obesity and metabolism, and Jimmy had invited me to discuss these topics on his show.

Due to a confluence of events, I've decided that this is not the best time to do the show.  I want to be clear that I don't intend this as a rebuke of Jimmy Moore or his show-- most of my reasons for postponing have nothing to do with Jimmy.  Thanks for your understanding.

Overfeeding and Elevated Insulin

It's commonly accepted in the obesity research community that fat gain causes insulin resistance and an increase in circulating insulin, and that this is a major reason why obese people usually have insulin resistance and high circulating insulin. Part of the rationale is that substantial fat loss by almost any means improves insulin sensitivity and causes circulating insulin to decline, and substantial fat gain from deliberate overfeeding causes insulin sensitivity to decline and circulating insulin to increase.  I recently cited three references to support this contention on another blog, and was challenged, so I decided to revisit these references to make sure I had understood them correctly (1, 2, 3).  Since I took the time to do this, I figured I may as well write it up for my readers, since these studies are quite informative.

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Food Reward Friday

This week's "winner"... the Heart Attack Grill's Quadruple Bypass Burger!

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Extreme Flu Activity in the US

A friend of mine came down with a nasty flu recently.  I checked Google Flu Trends, and found that flu activity is currently at "intense" levels throughout the US.  This is the highest flu activity Google Flu Trends has recorded in the last six years (image from Google Flu Trends 1/3/12).

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