Wednesday, July 27, 2011

Dietary Guidelines for Americans, My Way

I just saw this on BoingBoing.  Simple but true. 

This image was created by Adam Fields

The people who design government dietary guidelines are gagged by the fact that politics and business are so tightly intertwined in this country.  Their advice will never directly target the primary source of obesity and metabolic dysfunction-- industrially processed food-- because that would hurt corporate profits in one of the country's biggest economic sectors.  You can only squeeze so much profit out of a carrot, so food engineers design "value-added" ultrapalatable/rewarding foods with a larger profit margin.

We don't even have the political will to regulate food advertisements directed at defenseless children, which are systematically training them from an early age to prefer foods that are fattening and unhealthy.  This is supposedly out of a "free market" spirit, but that justification is hollow because processed food manufacturers benefit from tax loopholes and major government subsidies, including programs supporting grain production and the employment of disadvantaged citizens (see Fast Food Nation).

Tuesday, July 26, 2011

Interview on Super Human Radio

Today, I did an audio interview with Carl Lanore of Super Human Radio.  Carl seems like a sharp guy who focuses on physical fitness, nutrition, health and aging.  We talked mostly about food reward and body fatness-- I think it went well.  Carl went from obese to fit, and his fat loss experience lines up well with the food reward concept.  As he was losing fat rapidly, he told friends that he had "divorced from flavor", eating plain chicken, sweet potatoes and oatmeal, yet he grew to enjoy simple food over time.

The interview is here.  It also includes an interview of Dr. Matthew Andry about Dr. Loren Cordain's position on dairy; my interview starts at about 57 minutes.  Just to warn you, the website and podcast are both full of ads.

Wednesday, July 20, 2011

Weight Gain and Weight Loss in a Traditional African Society

The Massas is an ethnic group in Northern Cameroon that subsists mostly on plain sorghum loaves and porridge, along with a small amount of milk, fish and vegetables (1, 2).  They have a peculiar tradition called Guru Walla that is only undertaken by men (2, 1):

Wednesday, July 13, 2011

Simple Food: Thoughts on Practicality

Some people have reacted negatively to the idea of a reduced-reward diet because it strikes them as difficult or unsustainable.  In this post, I'll discuss my thoughts on the practicality and sustainability of this way of eating.  I've also thrown in a few philosophical points about reward and the modern world.

Saturday, July 9, 2011

How Does Gastric Bypass Surgery Cause Fat Loss?

Gastric bypass surgery is an operation that causes food to bypass part of the digestive tract.  In the most common surgery, Roux-en-Y bypass, stomach size is reduced and a portion of the upper small intestine is bypassed.  This means that food skips most of the stomach and the duodenum (upper small intestine), passing from the tiny stomach directly into the jejunum (a lower part of the upper small intestine)*.  It looks something like this:

Tuesday, July 5, 2011

Liposuction and Fat Regain

If body fat really is actively regulated by the body, rather than just being a passive result of voluntary food intake and exercise behaviors, then liposuction shouldn't be very effective at reducing total fat mass in the long run.  People should return to their body fat "setpoint" rather than remaining at a lower fat mass. 

Teri L. Hernandez and colleagues recently performed the first ever randomized liposuction study to answer this question (1).  Participants were randomly selected to either receive liposuction, or not.  They were all instructed not to make any lifestyle changes for the duration of the study, and body fatness was measured at 6 weeks, 6 months and one year by DXA. 

At 6 weeks, the liposuction group was significantly leaner than the control group.  At 6 months, the difference between the two groups had decreased.  At one year, it had decreased further and the difference between the groups was no longer statistically significant.  Furthermore, the liposuction group regained fat disproportionately in the abdominal area (belly), which is more dangerous than where it was before. The investigators stated:
We conclude that [body fat] is not only restored to baseline levels in nonobese women after small-volume liposuction, but is redistributed abdominally.
This is consistent with animal studies showing that when you surgically remove fat, total fat mass "catches up" to animals that had no fat removed (2).  Fat mass is too important to be left up to chance.  That's why the body regulates it, and that's why any satisfying resolution of obesity must address that regulatory mechanism.

Saturday, July 2, 2011

Food Reward: a Dominant Factor in Obesity, Part VIII

Further reading

I didn't come up with the idea that excessive food reward increases calorie intake and can lead to obesity, far from it.  The idea has been floating around the scientific literature for decades.  In 1976, after conducting an interesting diet study in humans, Dr. Michel Cabanac stated that the "palatability of the diet influences the set point of the ponderostat [system that regulates body fatness]" (1).  

Currently there is a growing consensus that food reward/palatability is a major contributor to obesity. This is reflected by the proliferation of review articles appearing in high-profile journals.  For the scientists in the audience who want more detail than I provide on my blog, here are some of the reviews I've read and enjoyed.  These were written by some of the leading scientists in the study of food reward and hedonics:

Palatability of food and the ponderostat.  Michel Cabanac, 1989.
Food reward, hyperphagia and obesity.  Hans-Rudolf Berthoud et al., 2011.
Reward mechanisms in obesity: new insights and future directions.  Paul J. Kenny, 2011.
Relation of obesity to consummatory and anticipatory food reward.  Eric Stice, 2009.
Hedonic and incentive signals for body weight control.  Emil Egecioglu et al., 2011.
Homeostatic and hedonic signals interact in the control of food intake.  Michael Lutter and Eric J. Nestler, 2009.
Opioids as agents of reward-related feeding: a consideration of the evidence.  Allen S. Levine and Charles J. Billington, 2004.
Central opioids and consumption of sweet tastants: when reward outweighs homeostasis.  Pawel K. Olszewski and Allen S. Levine, 2007.
Oral and postoral determinants of food reward.  Anthony Sclafani, 2004.
Reduced dopaminergic tone in hypothalamic neural circuits: expression of a "thrifty" genotype underlying the metabolic syndrome?  Hanno Pijl, 2003.

If you can read all these papers and still not believe in the food reward hypothesis... you deserve some kind of award.