Of course, there are thousands of books, websites, and podcasts that would beg to differ. They're all marketing their own "unique" take on eating - be it primal, low-carb, low-fat, high-protein, or whatever. And they all promise theirs is the game changer.
The truth is, that nutritional strategy book you just bought may very well work for you. It may optimize your metabolism, increase your performance, clear up your skin, whiten your teeth, disinfect, and deodorize. Conversely, it may make you feel lousy, ending up as another tome in the "failed diet" section of you bookshelf.
It's not the diet's fault. And it's not your fault. The fact is, everyone's body is different, therefore we react differently to different stimuli. Just as our personalities have formed via an intricate dance between our DNA and our life experiences, our bodies have become unique machines thanks to these two factors as well.
The 25¢ term for this is "biochemical individuality." It was coined in the fifties by Dr. Roger Williams. Although he's better known for discovering and naming pantothenic acid (vitamin B5), biochemical individuality was Dr. Williams' passion. As he states in the first chapter of his aptly named book, Biochemical Individuality, "All geneticists are agreed that what is inherited by all organisms from their forebears is a range of capacities to respond to a range of environments. The characteristics that an organism possess are fundamentally the outcome of the interaction of heredity and environment."
When Williams wrote "practically every human being is a deviate in some respect," he wasn't referring to whether you preferred cotton or leather briefs. He was pointing out that we're all a little different, therefore our individual needs are different as well. One example of this is our physiology reactions to nutrients.
A great example of this arrives via something called apolipoprotein E (apoE). Apolipoproteins are proteins in the body essential for fat metabolism, including the delivery of fat-soluble vitamins and cholesterol. ApoE is a subclass of apolipoprotein. "Normal" apoE is referred to as apoE3, but the genes that map out apoE can produce versions in some people known as ApoE2 and apoE4, which have been associated with a number of health issues, including Alzheimer's disease and atherosclerosis.
Now here's the part that affects your diet. In 2004, Spanish researchers took a look at how varying fat and carbs influenced LDL ("bad cholesterol") particle size. It's generally believed that lower LDL levels are healthier. However, it's also believed that larger LDL particle size (as opposed to the concentration) reduces the risk of heart disease. What the researchers discovered was that subjects with "normal" ApoE3 experienced increased LDL particle size from a diet slightly higher in fats, whereas people with apoE4 experienced increased LDL particles with a more carb-centric diet. In other words, it appears that some people in the study reduced their risk of heart disease with fat, while others did so with carbohydrates ñ and the deciding factor was the expression of their genes.
That's just one, small example of how your genes can influence things. Obviously this is pretty cutting edge, complex science. Therefore, we're a few years away from looking at your gene map to determine your perfect diet. Of course, that doesn't mean you can't look for clues yourself. For example, if you prefer anthropology over biology, you can always look to your ancestors. It could very well be that the reason many Americans benefit from the monounsaturated fat-rich Mediterranean diet is that many of us come from Southern European or Middle-Eastern descent, where that types of food has been consumed for centuries.
But while it never hurts to do a little research into your ancestors, it's even more important to listen to your own body. Look back to points in your life when you were especially healthy or unhealthy and note what you were consuming. Same with your day-to-day eating. Keep a nutrition log, saving space in it to note training and race results. Odds are, you'll quickly start noting connections between diet and performance.
Also, don't be afraid to be a human Guinea pig. I'd steer clear of the more fringe diets unless you really understand what you're doing, but otherwise, try South Beach or Paleo or Mediterranean or whatever diet book Oprah is plugging this week. Just don't get lost in the dogma. If it works for you, great. If not, don't be afraid to shelve it and try something new. Eventually, you'll find your game changer, but it's up to you and not some random celebrity to figure out which one.
Denis Faye been a professional journalist for 20 years, writing for Surfer, the New York Times, the Los Angeles Times, Los Angeles Magazine, Outside, Wired, Men's Health, Men's Journal, GQ, Surfer, and Pacific Longboarder. He credits a 5-year jaunt through Australia for a 50 pound weight loss and his transformation into the fitness and sports enthusiast he is today. His sports include swimming, scuba, trekking, rock climbing, mountain biking, spelunking, and -- most importantly -- surfing. Denis writes for Beachbody, which provides effective and popular workout videos, including the Insanity Workout, a high intensity interval training program for total body conditioning.