Catherine Shanahan, MD
Nov 21st, 2011
A lot of folks keen on losing weight have been convinced that a diet low in fat and protein and high in carbohydrates is the way to go. Seems intuitive, doesn’t it?: Don’t eat fat and you won’t get fat. That’s why, odds are, this year someone at your Thanksgiving table will be giving thanks without giving your perfectly browned holiday turkey a second look. Instead they’ll be opting to load their plate with their favorite high-carb “health foods”—sweet potatoes, stuffing, and cranberry sauce.
Grain-fed turkeys gain weight faster but have significantly smaller brain size than their omnivorous wild cousins of the same breed.
If you’re a regular reader of my blogs, you already know what I think of high-carb diets as a means for losing weight: I’m not a fan. But today, I’d like to skip the weight loss discussion and, instead, focus on some of the unintended health consequences of cutting healthy fats and proteins from your diet.
It’s Thanksgiving, so let me bring your attention to a study that came out a few years ago that focused on turkeys. According to the study, turkeys fattened up on an all-grain diet were found to have brains that had failed to grow normally: The all-grain turkey brains weighed in at slightly over two-thirds the weight of the brains of turkeys in the wild—turkeys with full access to the bugs, worms, and small lizards typical of a turkey’s natural omnivorous diet. That’s right, I said “omnivorous diet.” If you were fortunate enough to catch the recently aired PBS documentary “My Life as a Turkey,” you know that wild turkeys are complex and highly social creatures who hunt and poke, in addition to seeds and grasses and tiny sprouts, for all manner of creepy crawly things—caterpillars, worms, and shiny green grasshoppers, to name a few.
To a family in their Volvo driving by an open field filled with wild turkeys, the birds appear as a head-bobbing coterie of gentle grazers sunbathing and promenading through windswept grass. To a grasshopper clinging to the end of one of those grassy stalks, however, those same birds represent a fast approaching phalanx of razor-beaked predators. Grasshoppers know, intuitively, what we often forget: Turkeys are, after all, meat eaters, and they are voracious.
Which brings us back to the turkey study: An unnatural, all-grain diet winds up gobbling up nearly a third of a turkey’s total brain mass. So given that turkeys are omnivores, might these omnivores have something to teach us about the health of other omnivores, like humans, placed on an unnatural low-protein, low-fat diet?
Could we be putting our own brain health at risk by adhering to a low-fat, high-carbohydrate diet?
After decades of clinical experience, I would have to answer yes. Like our omnivorous feathered friends, our brains need the requisite nutrition to grow, develop, and function properly. Therefore, people may be placing their health at some peril when they choose to deprive their bodies of the full spectrum of natural proteins and fats. It’s no wonder, then that as a result of cutting fats and cholesterol (15% of your brain’s weight comes from cholesterol) many people find themselves dealing with memory deficits, or metal fog or depression. (Results may vary depending on your unique metabolic patterns.)
What should we take from from all this? First, a Thanksgiving turkey raised humanely—in a natural, open-air environment with free access to forage—is a lovely thing. But it ain’t cheap; that’s why the price sticker on a free-range turkey can make your jaw drop. If you discover such a free-range turkey, properly prepared, on your table, it’s definitely something worth giving thanks for, first to the bird, then to the farmer, and then to whomever and whatever else you feel deserves your thanks. It is, at once, a sacrifice and a blessing.
A traditionally-cooked, lovingly prepared Thanksgiving dinner (with a good glass of wine) is one of the most soulful and healthful things we do all year. Should we embrace it, or feel guilty about it?
As far as this doctor is concerned, that’s a no-brainer.
Happy Thanksgiving, everybody!