Day: July 6, 2012

Interesting Information:  July 6, 2012

“What Really Makes Us Fat”

Husband John reads The New York Times every Sunday.  It’s a national paper, and we are lucky to be able to get a national paper way up here in Mid-Coast Maine.  We don’t get The NYTs until mid-morning on Sunday, but we do get it delivered to our driveway–which did not happen until about a year ago.  Before that time, one had to go to a nearby market mid-morning on Sunday to get a copy.

I rarely have time to read the Sunday paper, so John brings me articles in which he knows I’ll be interested.

This Sunday he put Gary Taubes’ “What Really Makes Us Fat” at my place at the dining room table.

I’ve written about Taubes’ work in my essays.  He’s a careful researcher, and he’s telling a story that has a lot of scientific data behind it but which isn’t catching much fire in the mainstream understanding of how the body works with regard to obesity.  His work has pretty thoroughly debunked the “calorie is a calorie” and you-just-need-to-cut-back” theory of fat accumulation–showing that what kind of calorie one eats does matter rather a lot.

In “What Really Makes Us Fat,” Taubes cites a very recent article (last week) in The Journal of the American Medical Association detailing the results of a clinical trial by Dr. David Ludwig of Boston Children’s Hospital and his collaborators.  This study, writes Taubes, speaks to a fundamental issue–what causes obesity.

Ludwig’s team did something that has never been done before.  First, explains Taubes, they “took obese subjects and effectively semi-starved them until they’d lost 10 to 15 percent of their weight.  Such weight-reduced subjects are particularly susceptible to gaining the weight back.  Their energy expenditure drops precipitously and they burn fewer calories than people who naturally weigh the same.  This means they have to continually fight their hunger just to maintain their weight loss.”

Next, “Dr. Ludwig’s team then measured how many calories these weight-reduced subjects expended daily, and that’s how many they fed them.”  But, the subjects were “rotated through three very different diets, one month for each.  They ate the same amount of calories on all three, equal to what they were expending after their weight loss, but the nutrient composition of their diets was very different.”

One diet was low fat so was high in carbohydrates–it’s the “diet we’re all advised to eat:  whole grains, fruits, vegetables, lean sources of protein.”  One diet had a “low glycemic index:  fewer carbohydrates in total, and those that were included were slow to be digested–from beans, non-starchy vegetables and other minimally processed sources.”  The third diet was Atkins, which “is very low in carbohydrates and high in fat and protein.”

The “results were remarkable” write Taubes.  “Put most simply, the fewer carbohydrates consumed, the more energy these weight-reduced people expended.  On the very low-carbohydrate Atkins diet, there was virtually no metabolic adaptation to the weight loss.”

On the low-fat diets, participants “had to add an hour of moderate-intensity physical activity each day to expend as much energy as they would effortlessly on the very-low-carb diet.  If the physical activity made them hungrier–a likely assumption–maintaining weight on the low-fat, high-carb diet would be even harder.”

Taubes notes that if we consider the weight-reduced participants as being “pre-obese,” their reactions to foods tells us what can make us fatter.  This study showed that “the fewer carbohydrates we eat, the more easily we remain lean.  The more carbohydrates, the more difficult.  In other words, carbohydrates are fattening, and obesity is a fat-storage defect.  What matters, then, is the quantity and quality of carbohydrates we consume and their effect on insulin.”

Taubes notes that “from this perspective, the trial suggests that among the bad decisions we can make to maintain our weight is exactly what the government and medical organizations like the American Heart Association have been telling us to do:  eat low-fat, carbohydrate-rich diets, even if those diets include whole grains and fruits and vegetables.”

Taubes notes that these conclusions are controversial, and he calls for experiments to be “replicated by independent investigators.  We’ve been arguing about this for over a century.  Let’s put if to rest with more good science.   The public health implications are enormous.”

In his books, which I wrote about in my essays on this blog, Taubes discusses many ongoing clinical trials and numerous obesity clinics (like the one at Duke) which are showing that people lose weight and improve their health data on an Atkins-type diet.  Many other diets utilize parts of the Atkins approach–Paleo and GAPS among them.