Volume 6, Number 1: Spring Equinox, 2004

The Evolution of Our Diet - BC Diabetes Foundation

Dr. Eric G. Norman PhD

Staff Member with the Division of Endocrinology University of British Columbia, Vancouver, B.C.

The food business is a strange blend of commerce, fads, media hype, multinationals, advertising, book publishing, research articles, supplements.. the list goes on. While I admit that some of these people have the best interests of your health at heart, many if not most, are in it for the buck. You could be buying a pair of shoes or a new suit for all they care as long as they get your consumer dollar. The nice thing about a pair of shoes that don’t fit or a suit that just doesn’t cut it is that you know pretty quickly. Either the blisters on your feet tell you or a kind friend lets you know the suit you thought was a deal would look better hanging on that skinny guy in the cornfield. Food intake is different. What tastes and feels so good going down can have gradual deleterious effects on your body that go unnoticed for years until something breaks down. Worse yet are the ever changing and conflicting messages we are bombarded with regarding what is “healthy” for us.

Who do you believe? In answer to that I would say believe yourself. Read everything with an open mind. Consider the source, the evidence, seek out the references if possible and ask yourself, “Does this make sense?” The latter question is one I try to ask myself all the time with respect to the deluge of nutritional advice we see or hear almost every day.

Diet Evolution

When we use the term diet in this article we are referring to general food intake and not reduced or restricted food intake as in dieting. There have been many articles recently that make reference to anthropological diets with the assumption that since our ancient ancestors never experienced disease they must have had a far healthier diet than the one we now consume. This could be true and we’ll discuss this later but certainly they had a more active lifestyle and probably had a better balanced caloric budget than we do. Their level of activity in obtaining food was balanced by the food calories obtained and as such they stayed fit and healthy. At times when excess calories were available they most likely gained some weight but that would be in anticipation of hard times when food was scarce and they would have to rely on their body’s reserves. For most people in developed countries the annual cycles of food scarcity never happen. There are endless calories, which when combined with poor judgement or weak wills lead to rates of obesity unheard of in human history.

There is an interesting aside here in terms of the prevalence of type 2 diabetes. It is hypothesized that in the past individuals with a genetic predisposition to rapid fat storage would have had an evolutionary advantage when confronted with a period of food shortage. This makes sense given that many of our ancestors certainly would have had to confront periods of near starvation and rapidly storing fat calories when food was abundant would be a survival advantage during difficult times. That genetic advantage turns out to be a disadvantage in our society since food is rarely scarce. In those individuals with a predisposition to rapid fat storage and available endless calories there is excess and un-required fat storage, progression to increased insulin resistance and eventually type 2 diabetes. It is important to note here that this genetic predisposition represents a potential for fat storage but typically type 2 diabetes will only present itself when there is excessive caloric intake in the absence of balanced energy-burning activities.

Efforts to generalize a single anthropological diet really make no sense since the geographical location often dictated the diet. ‘Eat locally, think globally’ was probably their slogan out of necessity rather than environmental concerns. In fact there would have been Paleolithic diets composed entirely of plants, others entirely of animals and a range of combinations, largely dictated by what was available. This simple fact emphasizes one thing: Humans are phenomenally adaptable in their ability to meet caloric and nutritional needs with any variety of foods.

Some of you who have read this newsletter for a while may recall the article I wrote regarding the findings of the heart protection study where cholesterol lowering medications were used in a large study population and demonstrated a significant reduction in heart attacks and strokes (Vol.3 No.4). One of the key messages behind this study was that lowering the LDL (the low density lipoprotein, ‘bad cholesterol’) with the medication Zocor (a statin) could help to reduce hospitalization and surgeries and ultimately save the health care system significant amounts of money. Keep in mind that this pharmaceutical intervention (Zocor 40 mg once per day) would come with it’s own hefty price tag if applied to the 10-15% of the population at risk. In addition, the Zocor intervention did nothing for nutritional wellness.

There was an interesting study that appeared not long after that which was done in a smaller group of people and showed that an ‘ape diet’ was just as effective as a statin (in this case Lovastatin) at lowering the bad cholesterol. This was a Canadian study headed by Dr. David Jenkins at the University of Toronto and published in the prestigious Journal of the American Medical Association. This study randomized 46 men and women to one of three groups: a. A low-fat diet, b. A low-fat diet plus 20 mg lovastatin (Mevacor) and c. An ape diet. The latter consisted of an easy to prepare menu including such foods as oat bran bread and cereal, soy drinks, fruit and soy deli slices. They list a typical dinner as consisting of tofu bake with eggplant, onions and sweet peppers, pearl barley and vegetables. This really is a diet rich in nuts, fibrous grains and vegetable proteins. This was intended to be like an anthropological diet. It was unfortunate that this work didn’t get as much exposure as the results of the heart protection study since the message is quite powerful. Diet can make a difference. Many advocates of statin therapy have argued that diet could not achieve the significant reductions in LDL observed with statin use. In this study however, the ape diet reduced the LDL by almost 29% compared to the 30.9% reduction observed in the statin treatment arm. It’s all a matter of compliance, whether you’re popping a pill or consistently embracing healthy food choices. The diet also lowered the C-reactive protein, a blood protein used as a risk marker for heart disease. An interesting comment from the author with respect to dieting and being hungry. Dr. Jenkins stated “the trouble was that the dieters were too full. We had to force feed people to get them not to lose weight. So that is a problem. The diets are very filling. So for those people who don’t want to lose any weight, this diet is very filling and they may have trouble maintaining weight “. My response to this comment is that the majority of individuals with elevated cholesterol requiring some intervention are overweight and some weight loss may actually be beneficial as long it is done slowly and with adequate nutrition.

So where does this leave us? Once again it all comes back to balance, moderation and listening to the body. Which leads us to the ‘Low Carb’ craze that is everywhere you look now. The hype seems to be based largely on anecdotal evidence rather than science. Those studies that have been done suggest some short-term weight loss but after 12 months there seems to be little benefit with respect to weight loss.

I asked a dietician who specializes in diabetes her opinion on the low carb diets that so many people are embracing. Her response was:

“Would you take a medication that effects your metabolism that hasn’t been studied for longer than a year? Sadly low carb diets are being hyped as a quick painless way to lose weight or get better blood sugar control but no longer term studies exist to prove its effectiveness or its safety. What IS known to be safe, effective and healthy is including moderate amounts of high quality carbohydrate in the diet – fruits, vegetables, whole, unrefined grains and low fat dairy products. Until long term studies tell us otherwise that’s what I would stick with.”

Most dieticians will tell you that you should get 55% of your daily caloric intake from carbohydrate and the rest from fat and protein in approximate proportions of 20 to 25% making up the remainder. This is a guide and a good starting point but we are all different. Most of the low carb diets that are getting bashed tend to be extreme and the term LOW is both vague and relative. My personal feeling is that the majority of individuals could benefit from a lower relative carbohydrate intake. All I mean by this is that most people probably consume way too many carbs without realizing it since carbs can be hidden in many foods, especially the low fat foods that are so heavily marketed.

It should be mentioned that the obesity epidemic began around the early 1980’s and shows little sign of abating, based on current statistics. That rise in obesity coincided with the intense advertising campaigns by the food industry touting low fat foods which are loaded with sugar to achieve the desirable mouth texture. People consumed low fat foods with reckless abandon and here we are today in the midst of an obesity and diabetes epidemic of unprecedented magnitude. Who or what’s to blame?

There is no simple answer to that. Two things are certain though. If total caloric intake remains the same then a lower amount of one component means a higher amount of the remainder and this is true whether we’re talking low fat or low carb or low protein. The second point is that no two people are the same and a diet that works well for one may not work well for another. Although the fundamentals of human nutrition are generally universal we all have slight differences in metabolism and more importantly in our activity levels. Therefore, energy and nutritional needs will differ and how we respond to certain foods will vary. So what is the bottom line. It’s different for everyone. I would take a good look at your own diet and try to estimate the proportion of carbs, fat and protein. Try to identify the nutritious and less so elements. Be particularly careful with the hidden carbs so you get an accurate estimate. If the carb content is in the 55% range than you might think your diet is spot on. But is it? What if the majority of your carbs are nutritionally empty…or worse yet are found in processed junk food loaded with nasty preservatives, damaged fats and artificial sweeteners. And what if none of your fats are from whole foods or are all deep-fried in origin. Not so pretty. If this was the case you might fare better with a diet of 40-45% carbs but with whole grains, fruits and vegetables as the core of your carb sources. The putative risk of a lower percentage of carbs would certaiinly be outweighed by the benefits of better quality carbs. Carbs full of nutrients and fiber. Quality over quantity.

The human diet has evolved over millions of years but much of what we find on our plate has only appeared in the last 60 years or less. A mere blip in time but even in that short time we have seen many changes in our foods and our health. Yet over the millions of years humans have been shown to be adaptable to all types of foods ranging from mostly meat diets to vegetarian diets and all things in between. Perhaps we are not evolving quickly enough to keep up with our strange changing diet. If the current state of human health is any indicator of the quality of our diet I would certainly suggest that we are losing ground when it comes to nutrition and wellness despite the wealth of research and information available. Not to mention a wonderful selection of foods.

Eric Norman is a research scientist investigating blood vessel function in postmenopausal women and also works on a type 2 diabetes clinical trial.

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