Beyond the Paleo: Is it Really the Perfect Diet?

There has been explosive interest in the last few years in eating like our ancient, pre-agricultural ancestors:  following a hunter-gatherer pattern that would have been the norm in the Paleolithic Era (the "stone age").  The idea behind this is that agriculture has only been around for about 10,000 years, which is barely a blip on the evolutionary time scale.  Therefore, our genes are still adapted mostly to eating grass-fed meat, eggs, fish, fruits, nuts, and vegetables.  Foods that were introduced with agriculture - especially grains and beans - are harder to digest, and (so the logic goes) may actually contribute to health problems.

With my studies of biology in college, I am all on board the argument of genetic adaptation.  However, I think we need to look at the Paleo Diet critically to determine if it's really the healthiest way to eat.

• Peer-reviewed, published scientific studies about the Paleo Diet (of which there are fewer than ten) have mainly focused on short-term changes in specific parameters, like body weight, blood sugar, and blood cholesterol levels.  While there is definite benefit in these areas, the research has not gone as far as to prove lower risk of chronic disease or mortality (i.e., risk of dying early).
• The complete elimination of grains contradicts many studies that show decreased risk of chronic metabolic diseases.  Last month, Chinese researchers published data on over 367,000 participants, showing decreased all-cause mortality (that is, dying for any reason) with high consumption of fiber-rich whole grains.
• The argument that our genes have not had time to adapt to an agricultural diet ignores some biological nuances.  Sometimes genetic mutations can confer an advantage, and spread quickly -- the best example of this is the ability to produce the lactase enzyme into adulthood, which appeared just a few thousand years ago.  This allowed some populations to survive better than their neighbors, by taking advantage of dairy as a source of nutrition.  Another wrinkle is the relatively new field of epigenetics, which has found that though our genetic code may not change much, certain genes may be "turned on" or "turned off" (biochemically) in response to environmental pressures.  This can happen within a single generation, and the changes can even be passed on to offspring.

The Paleo Diet can serve some important functions.  As a structured system, it is a good way to break our addiction to sugar and refined carbohydrates, which is one of the leading causes of chronic disease.  By eliminating many common foods, the Paleo Diet can also serve as a tool to help identify foods that may be causing inflammatory reactions in the body.  For the long term, however, I still recommend the Mediterranean Diet (including - gasp! - whole grains), which has a mountain of evidence on improved health outcomes and longer lifespan.

Are You Sitting Down? Think Again...

Imagine two co-workers:  one slim, the type who can seem to eat anything without gaining a pound -- and therefore does not feel the need to exercise; the other one overweight, but who works out regularly.  In spite of your latter colleague's efforts, he has found it very difficult to lose weight.  Which one is at greater risk for health problems down the road?

The answer is not so clear-cut, since both obesity and physical inactivity have been linked to chronic diseases:  cardiovascular disease, diabetes, osteoarthritis, etc.  If you were forced to choose, though, it appears more and more that keeping physically active is the more important variable for decreasing health risks.

• Australian researchers (1) recently found that being sedentary accounts for about half the risk for cardiovascular disease in middle-age women -- more than obesity, high blood pressure, or even smoking.
• Recent studies in BMJ (the British Medical Journal) found that for older adults, light daily physical activity decreased the disability associated with knee arthritis (2), and poor physical fitness nearly quadrupled the risk for all-cause mortality (death by any cause) (3).
• While many studies have focused on light-to-moderate exercise, a new study in the Journal of the American College of Cardiology looked at something a bit higher impact -- namely running -- and found that running, even as little as 5-10 minutes per day, decreased cardiovascular and all-cause mortality risk by 30-50%. (4)
• Author Nilofer Merchant has compiled the research, and calls sitting the "new smoking" -- the big public health scourge that needs to be addressed in the 21st century.

What can you do today to incorporate more physical activity?

• Park a little further from your destination
• Walk the dog a little further each morning
• Jog in place during each commercial break on TV

Our bodies are designed for exercise throughout life -- so keep it moving!

1. Br J Sports Med. Published online May 8, 2014.
2. Relation of physical activity time to incident disability in community dwelling adults with or at risk of knee arthritis: prospective cohort study.  BMJ 2014;348:g2472
3. Physical capability in mid-life and survival over 13 years of follow-up: British birth cohort study.  BMJ 2014;348:g2219
4. Leisure-Time Running Reduces All-Cause and Cardiovascular Mortality Risk.  J Am Coll Cardiol. 2014;64(5):472-481. doi:10.1016/j.jacc.2014.04.058

Coffee: Superfood or Death Sentence?

Earlier this year, I outlined some of the amazing health benefits associated with regular coffee consumption.  These include a decrease risk of chronic diseases such as diabetes, Alzheimer's disease, and endometrial cancer; pain reduction as among its benefits too.

Now, new research from the Mayo Clinic (1) makes us pause and reflect on how much is too much of a good thing.  I often hammer that old adage, "all things in moderation;" in this case, moderation appears to be 4 cups of coffee per day.  More than that raises the risk of death for people under age 55.

Researchers looked at data from the Aerobics Center Longitudinal Study, which examined dietary habits and health data from over 43,000 participants over the course of 31 years.  For folks under the age of 55 who drank more than 28 cups of coffee per week, all-cause mortality risk increased by over 50% for men, and more than doubled for women.  The direct cause of this association is unknown, but seems to be unrelated to coffees cardiovascular effects.

One of the important points to keep in mind is that a "cup" in this study is defined as 8 fluid ounces; the cutoff point therefore seems to be about 32 ounces per day.  The "cup" markers on your coffee pot are 6 ounces each, so the limit would be about five of those cups.  If you prefer to get your coffee on the go, this would translate into only two "grandes."

This study leaves a lot of questions, such as the association of caffeine on health (the study didn't differentiate between regular and decaf coffee), the actual biological mechanisms of coffee (it has hundreds of phytochemicals besides caffeine), and the confounding factor of smoking with coffee consumption.  In the meantime...  Come on, people, four cups per day should be plenty for anyone.  In fact, beyond the first one or two cups of the day, why not explore the benefits of other healthful beverages such as green tea?

1.  Liu J, Sui X, Lavie CJ, et al. Association of coffee consumption with all-cause and cardiovascular disease mortality.Mayo Clin Proc 2013; DOI:10.1016/j.mayocp.2013.06.020.