Michelle keeps threatening me that she is going to make this her own personal blog since I very rarely write anything. I guess I had better step up and say something.
One of my big pet peeves is pseudoscience, particularly when it involves health and fitness issues. I saw a short video yesterday entitled "Why Diet Soda Makes You Fat." As a drinker of diet soda and as a 40 year old man that has trouble losing weight even though I put in about 10 hours of hard cardio and resistance training a week, I was interested. Unfortunately, it was a load of dung. The guy in the video started talking about how most of the food we eat these days (including diet sodas) are highly acidic and this "acidification" of our body makes us leach minerals such as calcium, magnesium, and iodine. Iodine is extremely important to our metabolism because it is used by our thyroid gland to make the hormones T4 and T3 which, among other things, help to increase our metabolism and therefore burn more calories. What he over looks is that it is nearly impossible to acidify our body. If our blood pH decreases below 7.35 (normal physiological pH ranges from 7.35 to 7.45) we would be seriously sick. The other thing he over looks is that no matter what the pH of the food we intake, it all gets acidified in the stomach during the process of digestion (stomach acid pH is about 2). As food is released in small amounts into the small intestines, the pH is increased to physiological levels. There is also no evidence in the peer-reviewed, published biomedical literature that supports this body acidification and leaching hypothesis.
Now, I am not suggesting that we should all feel good about chugging vast amount of soda, diet or otherwise. Soda, particularly Mt. Dew and colas, have negative effects on our teeth. One of the traps I fall into is believing that because I am drinking a diet soda, I can eat more. Also, artificial sweeteners (and excessive sugar) are thought to perhaps be able to "train" our brains to crave sweeter foods. If we give into these cravings and eat that extra piece of cake, we increase our blood insulin levels. While good for glucose uptake, insulin inhibits fat metabolism (this is the basis of the Atkins diet).
In short, it is important to limit the over consumption of any one food - particularly those with limited nutritional value. We need to focus on eating nutrient rich rather than just calories rich foods.
On another subject, I am competing in my first Olympic distance triathlon this Saturday. It is a 1500 meter swim, a 40K (25 miles) bike ride, and a 10K run. I am not a very strong runner and am nervous about having to run 6.1 miles after everything else. This is also a very hilly course both for the bike (we climb nearly 14oo feet over all) and the run (700' overall). My goal is to finish in 2 hours and 50 minutes or less.