After a long quarter of school, my roommate and classmate Brian and I decided to get away for spring break. Bend was our destination. We spent three days and two nights enjoying the scenery and forgetting about homework. Our first night out we went to hear some live music and I ran into Jeff Browning. Jeff is an amazing trail runner who has run 23 races of 100-mile distance and has won 14 of them! He is a professional athlete and lives up to the title. I like reading about the top athletes and their blogs, so I already knew what he looked like. He was easy to spot at the bar because of his unique style. I had to say hello and am glad that I did. Jeff studied nutrition quite a bit in college. Once I told him that I am studying nutrition now we delved into the topic very quickly. Jeff recently switched to a high fat diet. His carbohydrate intake is only 15% of his total caloric intake and his is fat intake is a whopping 70%. I have been a skeptic of a high fat (ketogenic) diet forever; it just doesn't seem right and goes against so much of what I have learned. Many of my teachers are naturopathic physicians that have years of clinical experience. However, hearing a great athlete that I admire talk about the drastic changes that he felt once he changed his diet to high fat made me curious. I will read the two books that he recommended with an open mind and see what happens. But...before I entertain this new idea I would like to list a few reasons why I don't think a ketogenic diet is good for everyone. I know that I said I would keep opinions to myself in my blogs but come on, opinions spice things up.
1.Digestion. Fat requires bile, a gel like substance that helps fat breakdown. Bile works like a detergent by mixing a nonpolar substance (fats) with a polar substance (water) so that fat can move through the digestive tract and be metabolized. Not everyone produces ample amounts of bile to break down excessive fat. Those who have a gallbladder infection or gallstone have this problem and a high fat diet could potentially exacerbate the issue. My dad, someone with a fully functioning gallbladder, was supplementing ox bile with his food on a high fat diet because he was having digestive problems. Many fat sources also lack sufficient fiber which can lead to fewer bowel movements and potential disease.
2. Evidence. The best runners and athletes in the world eat a high carbohydrate diet. I do understand that there probably aren't that many athletes that feel the need to switch to a high fat diet. Perhaps the ratio of those who attempt the high fat diet and those who have success is high. Supposedly ketones (fats that are converted to a form similar to that of carbohydrates) burn easier and cleaner, but I'm still not convinced. Although science is always evolving and there is so much unknown, human trials produce the most compelling evidence. The evidence of a high carbohydrate diet for optimal performance is hard to deny. Whole foods prevent disease and the majority of them are high in carbohydrates. There is a lot of buzz and research about the Mediterranean diet being the healthiest. This diet is high in fat but still is derived primarily from carbohydrates.
3. Sources. Finding healthy sources of carbohydrates in the store is ridiculously easy and relatively inexpensive. Finding a large amount of healthy, inexpensive fats in the store becomes more difficult. If you want to approach a high fat diet in the healthiest manner you should be eating grass fed meats and butters. These items are neither accessible nor inexpensive for a great portion of our population. If you're vegan a high fat diet would consist of nuts, avocados, and oils. There are simply less whole foods that are high fat meaning less variety and higher consumption of animal based foods. The World Health Organization recently released undeniable research connecting processed meats and red meat to cancer. I think that animal products should be eaten in moderation because of their high concentration of saturated fats. On a high fat diet it is recommended to consume animal products in every meal.
4. Genetics. Claims that our ancestors lived primarily off of meat isn't true for everyone. Humans have been farming in different parts of the world since the Neolithic revolution 10,000 years ago. By 8000 BC meat was a rarity in most populations and the diet was primarily vegetarian. Salivary amylase, an enzyme that breaks down carbohydrates, is more frequently seen in higher numbers in cultures in which starches are the staple of the diet. These genes are evidence of a long history of humans eating grains, fruits, and vegetables. There are places in the world where the climate makes farming very difficult. The people from these areas do rely on meat as a staple food. I believe that knowing your ancestry can be very indicative of what you should be eating. Marketing one diet as a "fix all" is a fallacy. I promote a high fruit, high vegetable-based diet, but if I am working with a woman who has extremely low ferritin and iron levels, I would recommend increasing animal product intake. It is clear that there isn't a one size fits all. Michael Arnstein (another ultrarunner) could tell me about the same results that Jeff has seen by following a fruitarian diet.
Fat is really important in the diet. There are so many reasons why our body needs fat. Our cell membranes need it, the absorption of fat soluble vitamins (A,K,E, and D) is reliant on it, and it is a precursor to various hormones in the body. I am excited to see what I can learn and who knows, I might change my mind. There is a lot of research backing the idea and some aspects of high fat make sense to me already. High fat diets have been linked to lower rates of Alzheimer's and Parkinson's disease. As a nutritionist I need to do my part and educate myself more about other ideas. Even if it is an idea I disagree with, I should be educated about it enough to counter arguments. I have rejected other ideas for too long and that is something I should change. I have already been frantically studying and reading about ketogenesis and will be excited to share what I have learned in the near future.
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