To get the most out of this column, you'll need to picture some things too small to see in a number too large to comprehend.

But that will allow you to entertain an emerging theory as to why the percentage of overweight and obese people in the U.S. has skyrocketed in the last quarter century.These things you can't see with the naked eye are called microbes, and the number of them in your stomach right now totals well into the trillions. If processing a number with 12 zeros produces a pain akin to an ice-cream headache, focus on a much smaller yet equally fascinating one: microbes make up around 4 pounds of your body weight.Some of that weight comes from bacteria, and there are at least 1,000 different species inside you. These bacteria have more than 3 million genes, and here's where something akin to an ice-cream headache might begin again. Experts estimate that two-thirds of your gut microbiome - the phrase used when all of the microbes function together as a sort of community - are unique to you because the bacteria's genes are affected by where you live, what you touch, your present health, degree of stress, age, gender, and choice of foods.This unique community inside you could very well determine the success or failure if you diet, at least according to the latest research published last month in Cell Reports.Researchers used magnetic resonance spectroscopy on urine samples from about 50 genetically similar lab mice to assess what was going on in their guts. In other words, they viewed the molecules in the samples to establish how the microbe community in each was functioning. They then switched the mice from standard mice food to a high-fat diet.The mice gained weight, as expected.What was not expected were the varying amounts of gained weight. After all, only genetically similar mice were used, and the calorie intake and activity levels for all remained constant, so why did statistically significant differences in the amount of weight gained occur?Yet the differences didn't end there.As Catharine Paddock, Ph.D., reported in an article for Medical News Today, a harbinger of type 2 diabetes, glucose intolerance, increased in some mice but not others. The same held true for an increase in anxiety or a decrease in activity. Many of the differences did make sense, however - if you knew how to interpret the magnetic resonance spectroscopy of the urine samples taken before the high-fat diet began.The unique composition of gut microbes in the supposedly similar mice caused them to process the same high-fat diet differently. The co-senior author of the study, professor Jeremy K. Nicholson from Imperial College London, told Medical News Today that the study shows the "power" of the tens of trillions of microbes in your stomach "to influence" your health; furthermore, it suggests that the end result of your diet is affected "not only by your genes, but also the genes of your gut microbes."This research and Nicholson's views are important to this column because they corroborate concepts stressed for years, and especially in recent weeks.The first, initially dubbed The Snowflake Theory of Dieting, was a layman's attempt to explain how two people with seemingly similar body shapes following the same exercise and diet plans would lose significantly different amounts of weight. I knew nothing about gut bacteria in the 1980s, but I did know that even the bodies of identical twins had some physiological differences.With that in mind, I ventured that - just like the structure of snowflakes - no two human digestive systems broke down food into energy in exactly the same way. As a result, a large cross section of dieters should - repeat, should - have a varying results after following the same diet.The second concept this column constantly touts logically follows the first: that personal experimentation is needed for optimal health. For instance, my experimentation has demonstrated that one of the supposedly sacrosanct rules for maintaining optimal body weight, limiting calories consumed in the evening, does not apply to me.On a typical "easy" day when I limit my workout to an hour, nearly two-thirds of my calories are consumed after 5:30. Even on a Saturday or Sunday when I ride bike for as long as four and a half hours, more than 60 percent of my calories are consumed after 5:30.I commit an even bigger breach of dietary protocol by eating twice - sometimes even a third time - after going to bed. While I fully expected this habit to result in an increase in body fat once I hit my mid-50s, fortunately it hasn't.Unfortunately, hitting my mid-50s has created a greater loss of muscle mass than I expected. Known as sarcopenia, this natural wasting away of muscle as you age is inevitable, but can be mitigated through diet and weight training, so guess what I need to do?Heed my own advice and begin to experiment once again.