"So I should just think of bad carbs as the good-tasting ones."

My niece, who's in eighth grade, has begun attending Weight Watchers, so my brother asked me to talk to her about that and nutrition in general. A question of hers led us to last week's topic, the bad-carb/good-carb conundrum, and the quotation above was the way she assimilated my explanation.Which really is an on-target observation if you've allowed your taste buds to experience too much sugar, fat, and sodium through processed foods - and that she has. I told her if she dramatically limits her processed-food consumption for three weeks, her taste buds will readjust.Apples will taste sweeter. Steamed veggies will have more flavor. The lean hamburgers her mother broils for her will only need a bit - not a bath - of ketchup.Last week, you read that the obesity rate for U.S. adults has risen to nearly 38 percent. In medical circles, the term "obese" is usually applied to those 20 percent or more above the highest healthy weight for a person of that height.So if your doctor tells you that you're supposed to weigh between 172 and 180 pounds, yet you weigh 216 or more, you are labeled as obese.Another 30 or so percent of American adults weigh more than a healthy weight, but not by more than 20 percent. So if you weigh 192 when you're supposed to weigh between 172 and 180, your doctor designates you as overweight.Quite often, the overweight don't require specific medical care to lose weight, just a reexamination of their dietary practices.Sometimes, this weight loss can be incited by one key bit of information - like last week's explanation of "good" carbs and "bad" carbs. Since that's so, it's time to review one bit of dietary gospel that might do more damage than good: the belief that eating all foods in moderation is a suitable strategy for general health and weight control.This belief, cribbed from a quotation by Ben Franklin, has been used to argue against fad diets that feature one food, such as the grapefruit and cabbage diets. But the all-things-in-moderation advice had never been scientifically scrutinized until researchers at the University of Texas Health Science Center at Houston did so.In a media release about their findings, Marcia C. de Olivera Otto, Ph.D., first author and assistant professor in the Department of Epidemiology, Human Genetics and Environmental Science at the University of Texas, said, "'Eat everything in moderation' has always been a long-standing dietary recommendation, but without much empiric supporting evidence in populations. We wanted to characterize new metrics of diet diversity and evaluate their association with metabolic health."The researchers used long-term data from 6,814 participants in a heart-health study that required each subject to precisely list food consumption, including the number of different foods eaten in a given week and the distribution of calories of the assorted foods.The surprising discovery? Those who ate the most diverse diets gained more weight and increased their waist circumferences by 120 percent when compared to those who ate the least diverse diets. Additionally, a diverse diet did not reduce the incidence of type 2 diabetes or improve waist measurement when compared to those who did not eat a diverse diet.Moreover, the most diverse diets were measured for diet quality were found to be inferior to those that were not. The criteria used to determine quality came from the guidelines of DASH diet (designed to stop hypertension) and the Alternative Healthy Eating Index.Furthermore, the study found that those eating a more diverse diet ate fewer fruits and vegetables, yet more processed meats, desserts, and sodas than those characterized as eating a less diverse diet.While it's valuable to share any health study that contradicts conventional wisdom, it's more beneficial if I interpret the study's significance and suggest how you can implement it. In short, I have no doubt that most readers would benefit from a less-diverse diet. To explain why, consider those great anecdotal guinea pigs, professional bodybuilders.To look their best on stage, most pros diet strictly for about four months. By showtime, their body fat percentages have gone lower than current mortgage rates.They achieve this by not only consuming fewer calories - though most consume more during dieting than you'd believe - but also by limiting food choices. The reason is simple.Fewer choices mean fewer variables. Fewer variables mean greater control of your health and weight.Before you dismiss a limited diet as a too austere existence, see if you can make a list of three breakfast, lunches, and suppers that you thoroughly enjoy and also help your health.If you can, why not eat each every third day? If that doesn't create the improvements you desire, then you reduce your portions or rework your recipes.Just like the pro bodybuilders, you should see a big difference after four months or so. If at that time you're bored of eating the same meals, swap them with other healthy, enjoyable ones.Remember, fewer variables mean more control. That's why eating all things in moderation may not be as effective as first believed.