Just about the time you think you have things figured out, it becomes clear - sometimes painfully so - that you don't. That's what I love about three things I love: teaching language arts, racing a bicycle, and writing health-and-fitness articles.

The reading material that excites one class leaves another cold. The training schedule once so great for your legs grates up your legs if you're coming off of an injury or a few years older.And if I had a dime for every time I read valid research that in some way contradicted prior valid research ... well, I could fill my bathtub, toilet, and kitchen sink with something other than water.You may be at a loss as to why I love such uncertainty. I'm not.I don't want a paint-by-numbers life. I want to paint like Picasso. I don't want to go to Karaoke night. I want to write my own lyrics and sing off key day or night.I strive to do what the German poet Rainer Maria Rilke suggests: "Be patient toward all that is unresolved in your heart and love the questions themselves."And the question that I love the most: Could there be a better way?If there is, I want to know. I hope you do, too. So that, my friends, is the crux of today's column.************You've experienced hunger, no doubt. And no doubt you expected that sensation to cease once you consumed a considerable number of calories.But that doesn't always occur.Yet that was the way it was taught in high school and college classes not so long ago. Ending hunger, just like maintaining a certain body weight, is achieved by following a scientific formula predicated on the notion that 3500 calories equals a pound.According to a recent review of 462 papers, however, calories consumed and appetite satiety do not equate. In fact, in 51.3 percent of the papers, the reviewers did not find a link between the two.Okay, so maybe this isn't Copernicus discrediting Ptolemy's long-held belief that the Earth is the center of the universe, but for the calorie-conscious it's close. Not only does it help legitimize a concept that I've touted for years - nutrient partitioning - but it also lends credence to the belief that the types of bacteria residing in your gut play a crucial role in weight control.In the most recent research, Danish researchers transplanted the gut bacteria from human beings into mice. Some of the gut bacteria came from people who were overweight. Some came from people of normal weight.The mice given the injections of human gut bacteria were specially bred to have no bacteria in their intestines and were fed the same diet.Those given the gut bacteria from overweight humans gained more weight than those given gut bacteria from those of normal weight.Equally as significant, the researchers determined that gut bacteria composition affected the mice's ability to convert carbohydrates and fats into energy. This finding further weakens the old notion that "a calorie is a calorie is a calorie" and supports the key feature to the nutrient-partitioning theory: that calories from the three macronutrients are handled by the body far differently.In short, that's why diet programs featuring protein-based foods work. Protein is difficult for the body to transform into energy. Calories are wasted.And wasted calories never have the chance to become unneeded calories that are stored as body fat.It's also why dieters do better avoiding many forms of fat and virtually all simple - not complex! - carbohydrates. These calories are not only transformed into energy easily, but they also become body fat rather efficiently.This is one time you don't want you body to be efficient.Unfortunately, something else has been found to be far less than efficient: the glycemic index, the rating system once thought to a great double check for determining "good" and "bad" carbohydrates. In fact, the latest study detected such inconsistencies that it may no longer be a useful tool.In an article for the Tufts University's newsletter, the lead author of the study, Nirupa Matthan, PhD, a scientist for USDA Human Nutrition Research Center on Aging at that university, says, "If someone eats the same amount of the same food three times, their blood glucose response should be the similar each time, but that was not observed in our study. A food that is low glycemic index for you one time you eat it could be high the next time, and it may have no impact on blood sugar for me."The most recent work on the glycemic index and the most recent work with gut bacteria substantiates the statement that starts this column: that just about the time you think you have health-and-fitness things figured out, it becomes clear that you don't. But don't use that as the reason to give up the quest for optimal health and fitness.Use that as a reminder that the process is ever changing because you are ever changing and strive to find what works best for you right now.