Friday, December 26, 2014

Tuesday, December 16, 2014

Is Meat Unhealthy? Part V

In this post, I'll examine the possible relationship between meat intake and type 2 diabetes.  Type 2 diabetes is the most common form of diabetes, and it is strongly linked to lifestyle factors.

Non-industrial cultures

Non-industrial cultures have an extremely low prevalence of diabetes, whether they are near-vegan or near-carnivorous.  This is supported by blood glucose measurements in a variety of cultures, from the sweet potato farmers of the New Guinea highlands to the arctic Inuit hunters.  Here is what Otto Schaefer, director of the Northern Medical Research Unit at Charles Camsell hospital in Edmonton, Canada, had to say about the Inuit in the excellent book Western Diseases (Trowell and Burkitt, 1981):
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Friday, December 5, 2014

Wednesday, December 3, 2014

Is Meat Unhealthy? Part IV

In this post, I'll address the question: does eating meat contribute to weight gain?

Non-industrial cultures

I'll get right to the point: humans living in a non-industrialized setting tend to be lean, regardless of how much meat they eat.  This applies equally to hunter-gatherers, herders, and farmers.

One of the leanest populations I've encountered in my reading is the 1960s Papua New Guinea highland farmers of Tukisenta.  They ate a nearly vegan diet composed almost exclusively of sweet potatoes, occasionally punctuated by feasts including large amounts of pork.  On average, they ate very little animal food.  Visiting researchers noted that the residents of Tukisenta were "muscular and mostly very lean", and did not gain fat with age (1, Western Diseases, Trowell and Burkitt, 1981).

!Kung man gathering mongongo fruit/nuts.
From The !Kung San, by Richard B. Lee.
Another remarkably lean hunter-gatherer population is the !Kung San foragers of the Kalahari desert.  The !Kung San are so lean that many of them would be considered underweight on the standard body mass index scale (BMI less than 18.5).  Average BMI doesn't exceed 20 in any age category (The !Kung San, Richard Lee, 1979).  Is this simply because they're starving?  It is true that they don't always get as much food as they'd like, but on most days, they have the ability to gather more food than they need.  The fact that they are able to reproduce normally suggests that they aren't starving.  Richard Lee's detailed work with the !Kung San indicates that approximately 40 percent of their calories came from animal foods during his study period in the 1960s.  This was mostly meat, with occasional eggs when available.

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Monday, December 1, 2014

Recent Interviews

For those who don't follow my Twitter account (@whsource), here are links to my two most recent interviews.

Smash the Fat with Sam Feltham.  We discuss the eternally controversial question, "is a calorie a calorie"?  Like many other advocates of the low-carbohydrate diet, Feltham believes that the metabolic effects of food (particularly on insulin), rather than calorie intake per se, are the primary determinants of body fatness.  I explain the perspective that my field of research has provided on this question.  We also discussed why some lean people become diabetic.  Feltham was a gracious host.

Nourish, Balance, Thrive with Christopher Kelly.  Kelly is also an advocate of the low-carbohydrate diet for fat loss.  This interview covered a lot of ground, including the insulin-obesity hypothesis, regulation of body fatness by the leptin-brain axis, how food reward works to increase calorie intake, and the impact of the food environment on food intake.  I explain why I think proponents of the insulin-obesity hypothesis have mistaken association for causation, and what I believe the true relationship is between insulin biology and obesity.  Kelly was also a gracious host.  He provides a transcript if you'd rather read the interview in text form.