Tag Archives: diseases of civilization

Book Review: Good Calories, Bad Calories

Here’s my  review of good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease, by Gary Taubes, 2007.  I give it five stars on Amazon.com’s five-star system (“I love it”).

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This brilliant book deserves much wider currency among physicians, dietitians, nutritionists, and obesity researchers.  The epidemic of overweight and obesity over the last 30 years should make us question the reigning theories of obesity treatment and prevention.  Taubes questioned those theories and pursued answers wherever the evidence led.  He shares in GCBC his eye-opening, even radical, well-reasoned findings. 

Ultimately, this tome is an indictment of the reigning scientific community and public nutrition policy-makers of the last four decades.  That explains why, twoyears after publication, this serious, scholarly work has not been reviewed by the New England Journal of Medicine, the Journal of the American Medical Association, the American Journal of Clinical Nutrition , and the Journal of the American Dietetic Association (as of August, 2009).

In Part 1, Taubes examines the scientific evidence for what he calls the fat-cholesterol hypothesis.  More commonly known as the diet-heart hypothesis, it’s the idea that dietary fat (especially saturated fat) and cholesterol clog heart arteries, causing heart attacks.  Taubes finds the evidence unconvincing.  He’s probably right.

Part 2, The Carbohydrate Hypothesis, revives and older theory from the mid-twentieth cenury that is elsewhere called the Cleave-Yudkin carbohydrate theory of dental and chronic systemic disease.  In the carbohydrate theory,  high intake of sugary foods, starches, and refined carbhohyrates leads first to dental disease (cavities, gum inflammation, periodontal disease) then, later, to obesity and type 2 diabetes, coronary heart disease, perhaps even cancer and Alzheimer’s Disease.  These are, collectively, the “diseases of civilization.”

Part 3 tackles obesity and weight regulation.  Taubes writes that “…fattening and obesity are caused by an imbalance—a dysequilibirium—in the hormonal regulation of adipose [fat] tissue and fat metabolism.”  Think of the transformation of a skinny 10-year-old girl into a voluptuous young woman.  It’s not over-eating that leads to curvaceous fat deposits, growth of mammary tissue, and increase in height; it’s hormonal changes beyond her control. 

The primary hormonal regulator of fat storage is insulin, per Taubes.  Elevated insulin levels lead to storage of food energy as fat.  Carbohydrates stimulate insulin secretion and make us fat. 

Although it’s a brilliant book, by no means do I agree with all Taubes’ conclusions.  For instance, if carbohydrates cause heart disease, why is glycemic index only very weakly associated with coronary heart disease in men?  It’s way too early to blame cancer and Alzheimers on carbohydrates.  Primitive cultures may not exhibit many of the diseases of civilization because their members die too young.  Taubes is clearly an advocate of low-carb eating.  Why didn’t he directly address the evidence that fruits, vegetables, and whole grains in the right amounts are healthy?

I have to give Taubes credit for thinking “outside the box.”  His search for answers included reviews of esoteric literature and interviews with scientists in the fields of genetics, athropology, public policy, physiologic psychology, and paleontology, to name a few.

Towards the end of the book, Taubes describes a Mediterranean-style or “prudent” diet that is popular these days.  After five years of research for his book, he says that whether a very low-carb meat diet is healthier than a prudent diet “… is still anybody’s guess.”  It’s hard for me to put aside numerous observational studies associating health benefits with legumes, fruits, vegetables, and wholegrains.  So my “guess” is that the Mediterranean-style diet is healthier.  Perhaps the answer is different for each individual.  Heck, maybe the answer is low-carb Mediterranean.  Both Taubes and I are prepared to accept either result when we have proof-positive data.    

Taubes doesn’t base his opinions on late-breaking scientific results.  Instead, his research findings mostly span from 1930 to 1980, especially 1940-1960.  Once the fat-cholesterol (diet-heart) hypothesis took root around 1960 and blossomed in the 1970s, these data were ignored by the entrenched academics and policy-makers of the day. 

To be fair, I’ve got to mention this is not light reading.  A majority of people never read another book after they graduate high school.  Of those who do, many (like me) will have to look up the definition of “tautology,” “solecism,” etc. 

I was taught in medical school years ago that “a calorie is a calorie is a calorie.”  Meaning: if you want to lose excess weight, it doesn’t matter if you cut calories from fat, protein, or carbohydrates.  I really wonder about that now.

Steve Parker, M.D 

Additional Reading

Bray, George A.  Viewpoint: Good Calories, Bad Calories by Gary TaubesObesity Reviews, 9 (2008): 251-263.

Taubes, Gary.  Letter to Editor: Response to Dr. George Bray’s review of Good Calories, Bad CaloriesObesity Reviews, 10 (2008): 96-98.

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Filed under Book Reviews, Carbohydrate, Causes of Diabetes, coronary heart disease, Overweight and Obesity

What About the Paleo Diet?

Paleo diets have been increasingly popular over the last few years.  The idea is that, for optimal health, we should be eating the things that we are evolutionarily adapted to eat.  Those foods pre-date the onset of large-scale agriculture 10-12,000 years ago.  So grains and modern fruits and vegetables play little or no role in someone who has “gone paleo.”

My recollection from college courses years ago is that average lifespan in paleolithic times was perhaps 25-30 years, or less.  If you’re going to die at 25, it may not matter if you eat a lot of  wooly mammath, berries, insects, cholesterol, saturated fats, Doritos, Ding Dongs, or Cheetos.  The diseases of civilization we worry about today—coronary heart disease, high blood pressure, cancer, dementia, type 2 diabetes, etc.—don’t usually appear until after age 30.  Paleolithic Man worried more about starvation.

Jenny Ruhl, at her Diabetes Update blog, recently put much more critical thought than I into the concept of paleo diets.  Recommended reading.    

Steve Parker, M.D. 

Extra credit

For purposes of discussion, let’s assume that human evolution actually occurred over millions, or at least hundreds of thousands, of years.  In other words, assume that God didn’t make Adam and Eve in human form in one day.

The theory of evolution proposes that genes that allow an animal to live and reproduce more vigorously in a particular environment will be passed on to the animal’s offspringNature will select those genes to spread through the animal population over time, assuming the environment doesn’t change.  The offspring with those genes will be able to compete with other animals more successfully for food, shelter, and mates.  Factors that promote the persistence and inheritance of specific genes are called “selection pressure.”

Here’s an example of selection pressure.  Remember when you were in grade school on the playground, some people could naturally run faster than others?  Were you one of the fast ones?  If you’ve never seen it for yourself, take my word for it: Some people are naturally gifted with athletic genes.

Let’s say you and I are outside collecting berries and nuts in paleolithic times.  A saber-toothed tiger spots us and charges, hungry for a meal.  You don’t have to outrun the tiger: you just have to outrun me.  I’m slower than you, and get eaten.   I can no longer pass on my slow-running genes to the next generation.  You live another day and pass on your fast-running genes to your children. 

Viola!  Natural selection, via selection pressure, has promoted your genes over mine.

[The tiger also passes on her genes since she was fast and smart enough to catch me, preventing starvation of her and her offspring.] 

[I’m 99% sure I wrote the preceeding few paragraphs originally about a year ago.  My notes, however, hint that they may have been written by Dr. J., a regular contributor at CalorieLab.  Dr. J., let me know if I’ve plagiarized you and I’ll give you full credit and delete my writing.]

The paleo diet rationale seems to be based on an evolutionary argument: Certain foods were available to us during 99% of our evolution, so our bodies are adapted to work optimally with them.  For example, humans/humanoids/higher primates who were not suited to the available food did not survive and reproduce, so their genes were not passed on to us.

For most of human existence, maximum lifespan was probably 25-30 years, on average. If that’s as long as you’re going to live, it may not matter much what you eat. Eat paleo, vegetarian, McDonald’s, Atkins, or Mediterranean. Most diet-related conditions except overweight and under-nutrition are not going to be an issue before age 30. 

[The modern paleos argue that infant and childhood mortality were extremely high in paleolithic times.  If you survived childhood, you could easily live to be 50+.]

But now we live to be 80, long enough for diet-related diseases to appear. We have cancer, heart attacks, and strokes that paleo man never saw because he died of trauma or infection or starvation. We even see the expression of genes that were not subjected to survival or selection pressure: Alzheimers disease, Huntingtons chorea, some breast cancers, etc.  People with genes for these diseases reproduce before the genes do their damage.

In other words, we carry genes that don’t matter if you die at age 30. If you live longer, they express themselves, and I believe we can modify their expression through diet and lifestyle. And not necessarily the paleo diet.

I’m still thinking it through.

For the other side of the argument, visit Mark’s Daily Apple, At Darwin’s Table, or read Dr. Loren Cordain’s The Paleo Diet.

-Steve

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