I’ve tried to stay away from diet talk because there are so many different views on food choices depending on what individuals consider are important to them. Deciding what to eat used to be so much easier, and for many people in the world it still is – whatever you can find to survive. Now we have grocery stores on every corner, foods from all over the world at our fingertips, and media bombarding us with diet ideas. Your food choices are now dependent on whether you value cost, ethics, sustainability, convenience, weight loss, improved health, or whatever the commercials tell you is tasty. It's also not surprising that it's quite difficult to eat according to these values as they often don't align. For example, eating cheaply doesn't always mean eating ethically or conveniently (Malhi et al, 2009 - http://www.tandfonline.com/doi/abs/10.1080/19320240903346448). You are not longer a simple omnivore like out ancestors, but you have a choice to be labelled as vegetarian, vegan, pescatarian, raw-food eater, or "carniovre", with the list increasing almost daily. It's no wonder so many of us are confused about food.
I’m pretty bored talking about weight-loss diets, but what is interesting are the number of diets claiming to improve health and performance. I took a number of Applied and Sports Nutrition courses while I was completing my Kinesiology Degree and the information I learnt was pretty simple for athletes. The spark notes version is that depending on what your energy demands are you will tweak a certain Carb-Protein-Fat ratio, and maintain proper hydration and electrolytes. My brother is an Infanteer in the Canadian Forces and has an intense workout schedule as part of his job. He is surrounded by some incredible athletes who are capable of amazing physical feats and is obviously influenced by their successes. Over his time in the Forces he has tried a number of diets that his peers use and attribute to their almost in-human physical abilities. One of the diets he tried was the Palaeolithic Diet. This diet basically says that we should be eating the same foods as cavemen did - no processed foods, and lots of meat, fruits and vegetables. It is based on an assumption that cavemen had to be in excellent shape to survive, and were able to hunt for days without food. At first glance this does seem like a great idea and I agree that processed foods are a major cause of our obesity epidemic in North America. But, if you actually try the diet out without proper preparation you will soon realize that without processed foods it is extremely difficult to get any grains (breads, cereals, rice, etc) and therefore you enter into a very low carbohydrate situation and potentially become deficient in some B Vitamins. Your body and brain have been programmed to use carbohydrates as its first source of energy. The Paleo Diet states that over time your body with adapt to use protein and fat as its primary sources, which is true, but typically not ideal for the average person. My brother experienced this first hand as he went through carb withdrawals within the first three days, and began dreaming about loafs of bread, and feeling extremely low-energy and unwell. All it took was some fresh homemade granola bars to bring him back to a balanced diet.
I believe that the Palaeolithic Diet, like any other elimination diets, such as, vegetarianism, if done correctly and with proper education and preparation can be beneficial to health. There are a lot of scientific articles out there showing the health benefits to eating less meat, dairy, processed foods, etc, but you must learn how to get all the nutrients you need from other sources rather than just cut certain foods out of your current diet. A person could go crazy trying to stay on top of the current dietary trends, so it’s important to be critical of the information out there and to make up your mind based on personal experiences. FYI, coffee is back in the “healthy” column, soy was demoted to the “unhealthy” column, and my personal fave, drinking a glass of any kind of alcohol daily has now been shown to increase longevity. You be the judge.
The new fascination for my brother is the Blood Type Diet. I can believe that the Paleo Diet had some validity to it (never mind that most cavemen didn’t live past 30 and were probably in a state of perpetual starvation and disease), but I laughed when I heard about this Blood Type Diet. I had to investigate and what I found was naturopathic Dr. D’Adamo proposing that the different blood types (A, B, AB, O) somehow came about at different times in history as our ancestors developed new ways to hunt and gather foods, and by extension your blood type influences your personality and your stress levels (huh?). He recommends that different blood types should have different diets, different types of exercise, and different ways to deal with stress. Now, seeing as how blood type is really just determined by whether you have certain protein markers on your red blood cells (and this hasn’t changed much through our time as homo-sapiens), I have a hard time believing anything this guy says, although I have heard that there is a correlation between blood types and certain illnesses. The only real evidence he had on his website supporting this diet was that about 75% of participants “improved in a variety of health conditions”. If you read through the different diets you will quickly see that they are all very similar and are basically just promoting good eating practices, such as, eating smaller meals throughout the day, limiting sugar intake, increasing vegetable intake, and choose exercise instead of emotional eating. Of course this will improve the “health” (whatever that means) of participants coming from who-knows-what eating practices they had originally.
I went one step further trying to find any scientific, peer-reviewed journal articles that support this Blood Type Diet. To my complete non-surprise, I could only find 1 article on a study comparing blood type to health and this is what it says:
“The ABO blood group phenotype has been related to risk of myocardial infarction and type 2 diabetes mellitus, but there is no evidence that ABO blood group influences diet prescription for effective weight loss.”
“These data do not support the contention of a popular diet book that individuals with the A blood group phenotype should adhere to low-protein, vegetarian diets for health and weight management.”
I’m sold. Take the time to educate yourself on nutrition from a recognized organization like Health Canada or a Registered Dietician before you blindly jump into special diet being promoted to the public. If you want to read the article, the abstract can be found at:
http://www.citeulike.org/user/naturecure/article/924975
The FASEB Journal. 2006.
ABO blood group and diet prescription for weight loss
Johnston, et al. Nutrition, Arizona State University, 85212
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