Ever wonder why the science of nutrition is so fraught with controversy? Studying nutrition is difficult for a myriad of reasons, but one main reason is the fact that humans eat a very wide variety of foods which makes it extremely difficult to decipher which particular nutrients contribute to health and/or development of disease. We can't lock a group of people into a room for a year and demand that they only eat apples (though it might be an improvement for some).
Most whole foods contain many different nutrients and some may be more beneficial than others. It can be very challenging to measure the effect of just one nutrient much less a specific food or food group. Despite all the research there is still a lot we don't know about how specific nutrients combine to work and what cofactors are necessary for absorption and full expression of a nutrients' benefits. Add to this the fact that positive and detrimental effects from specific foods and nutrients can take many years to show up, and you begin to see just how complicated it really is.
So what can we believe? When we look at how human diets have adapted in very divergent environments we realize that there is not one right answer here. For years Eskimos consumed a very different diet than Native America Indians, yet both experienced periods of good health and low disease. While good genes certainly help, it is estimated that lifestyle accounts for 70-80% of life expectancy. Places like Okinawa, Japan and Ikaria, Greece are good places to look for guidance.
In Ikaria, a traditional Mediterranean diet is followed with low consumption of meat, dairy and sugar, and high consumption of organic (home grown) vegetables, greens, beans, herbs and olive oil. They consume some diary in the form of goat’s milk which is much easier to digest than cow’s milk. Stress is low and mid-day siestas are commonplace. One third of the population can expect to live to 90 (they are 10x more likely to live into their 90s and 100s). Dementia is virtually unheard of and rates of cancer and heart disease are much lower than other populations.
Okinawans are a fascinating study of the effect of diet and lifestyle on longevity. The oldest generation grew up on a diet high in fish, seafood, vegetables, seaweed, whole grains and soy products with little red meat and almost no dairy. They live an active lifestyle and once boasted the world’s best longevity rates (which is now held by Ikaria). It all began to change after the introduction of American style fast food in the 1970s. Since then, younger generations have become more sedentary and consume a diet much closer to a typical American diet. As a result, they suffer from high rates of obesity (about 50% of men over 40), diabetes and heart disease. Longevity rates are plummeting and the older generation who retain the traditional diet and lifestyle are outliving their children and even their grandchildren.
What can we learn from observing these two societies? Basically that if you want to live a long, healthy life you greatly increase your chances when you live an active lifestyle and stick to a whole food diet high in vegetables and low in red meat and dairy. I do believe that moderation is the way to go. If you love red meat eat it in moderation. but be sure to purchase the best quality meats you can afford. The effect of red meat on heart disease is still unclear, but many experts continue to advise moderation. No one supports the benefits of a diet high in processed foods and sugar – this is definitely not an area where there is any controversy (unless you ask companies like Coca-Cola and Nestle). The best advice for longevity is to cut down on processed foods and sugar, increase consumption of vegetables, live an active lifestyle and find ways to reduce stress.