Sunday, August 28, 2011

on gary taubes, author of "why we get fat"

normally i take a more conservative stance on dieting for wt loss. that is, while i know it's important to lose wt for the two-thirds of americans who are overwt or obese, i am sensitive to the wt loss mantra that pervades our society and has been over-used in the minds of some afflicted with body image issues and eating disorders. confusing? well, it is for me too. that is, i am sensitive to the needs and issues of those with ED (eating disorders) but i'm also sensitive to the needs and issues of those with excess wt....and pissed off, if you've read some of my previous blogs. pissed off because excess wt is in many cases avoidable or at least manageable and when i see the millions of unconcerned parents of little kids, and other adults or near adults, who seem not to be taking any actions to avoid wt gain, i know the drain on our medical systems and dollars that seem so selfishly being left open. that said, i keep reading.....

when a formerly obese but currently lean client - a surgeon - came in to consult about his exercise program, he informed me of gary taubes, author of "why we get fat" which was s sequel to "good calories, bad calories". both are catchy titles and both pitch the low carb diet. however, different from other books of this type, he goes thru the world history, literally, of how excess fat consumption may NOT be the source of excess fat DEPOSITION let alone metabolic consequences of obesity. historically speaking, there is a substantial body of accepted evidence from all kinds of trials and meta-analyses that demonstrates that hi insulin resultant from hi carb diets is the source of both obesity and heart disease/diabetes/metabolic syndrome...and maybe many cancers. his review of literature is comprehensive tho he does avoid alternative explanations for some of the supportive studies he uses when debunking the diet- or exercise-only methods of wt loss. more on that later. additionally, his review of biochemistry that anyone can almost make sense of - i write this pen in cheek because, while he does soften it up and masticate it for the common reader, never delude yourself to think you can understand the complexities of our hormonal and metabolic systems by his or anyone else's descriptions - is also compelling. let me summarize and synopsize this for you: simple carbs - anything refined, starchy, white - elevate insulin which causes all kinds of bad things in your body if you persistently run high in your blood stream. his diet advice, however, is more sane sounding than one might otherwise expect from this warning.

now, to his exercise critique, something about which i do know and am sensitive.

taubes contends that studies show exercise is not an effective way to lose wt. he uses two types of studies: clinical, where control groups and supervision/guidance are offered, and epidemiological, where you survey people in large numbers. of the first, often times wt loss, on AVERAGE, does not occur from either cardio or strength training. taken on the face of it, this would make it appear that exercise is only useful for health, not wt loss; and while this is clearly true, don't discount its ability to help with the latter. in fact, many lose wt by exercising for the following reasons: calorie use while exercising, calorie use to restore homeostasis (post exercise oxygen consumption, or what is referred to in the fitness lit as EPOC, exercise post oxygen consumption which to me puts the cart before the horse but never mind....), and body composition changes, esp from resistance training. now, can you lose as much as you might wish via exercise, and is it easy? NO, but it's not ineffective. and it does confer great health benefits even beyond those that are medical - such as increased vigor, function, and emotional stability. taubes acknowledges as much but does not equate these benefits to the ones he touts when he reviews the studies that support his preferred diet, low carbs. so, in one study where subjects lost almost 10# after 6 mos, which is not that impressive really, one could find exercise routines that do the same. but he argues that exercise actually stimulates eating, and he's wrong here, from two angles. first, exercise actually increases leptin sensitivity such that the hormonal signaling that shuts off appetite if fat cells are satisfied does not need the enormity of output necessary to effect eating restraint. much as with increased insulin sensitivity, another benefit of exercise, if the body is better adapted to using hormones, the decreased hormone output not only conserves organic function (think pancreas when you think of insulin) but it also reduces negative effects of too much hormonal output overall (think hyperinsulinemia). furthermore, tho the exercise is hard to induce and maintain in many subjects, it does not stimulate so much as modulate hunger; minimally, it's another hour of the day you DON'T EAT. in fact, studies have shown that athletes, in hard training, lose wt often because they UNDEREAT. granted, the overwt/obese may compensate, and taubes does point that out, but with new studies recommending shorter bursts of higher intensities, i would think this type of compensatory eating - and even compensatory sedentariness, which taubes does not address - would be diminished, too.

now, as for large pop studies, self-reported exercise (over estimated) and diet (underestimated), esp if recalled over large tracts of time - like how many days/wk did you exercise at X% over the past year? - are inherently of nominal value. they may show why some succeed in accomplishing a study's goal - whether of wt loss or blood cholesterol reduction - but do not allow us to categorically state why some fail. we'd have to accuse them of lying, to the researchers and to themselves. no one wants to do that, right? taubes does not really address it when he accuses studies of exercise or low fat diets of failing.

that all said, let me pat him on the back for writing what i believe has not been writ large enough by authors promoting any sort of diet of the sort he promotes: he goes thru the various negatives of the higher protein/fat diets and explains them in ways that make the reader not pause but consider with some forethought the reality of taking on this kind of LIFESTYLE change. i emphasize lifestyle seriously because this is NOT a two week diet - if you have diabetes or have been overwt/obese for a long period of time, it may take months if not years to reverse your metabolism...and still some may not succeed to the degree to which they or their doc may like. and finally he presents the medico-legal problem inherent in his recommendation to docs: it's still outside the mainstream of government-supported recommendations so docs may be reluctant to put folks on this kind of diet. my advice: give patients the book, highlight certain features, and let the patient decide; then refer to a dietitian for specifics. and taubes i think could live with this, too.

so, my recommendation to readers who are interested in wt loss either from a personal or professional perspective: read this book, why we get fat, esp the last two chapters. if you want more of the history and science behind it, read the first 172 pages and/or read his other book, "good calories, bad calories", and decide for yourself.

my one caveat, and my daughter personifies this, is that vegetarians or vegans, or people like myself who don't eat red meat/pork, will have a harder time adapting to this kind of meal plan. hi pro/hi fat diets need to be creatively prepared to avoid mundanity; if you only know so many ways to prepare fish and chicken, good luck. otherwise, learn to cook better or learn to eat meat.

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Dr.Irv