I don't think the food groups "make" anyone believe anything. I use them, and understand the advantages (convenience) and the limitations (many foods don't fit neatly into one category, and some fit into several).
The problem isn't using food groups, it's not providing enough information for people to understand how to use the food groups as a tool.
Again (because I say this so often) it's a problem of oversimplification for convenience. We (as a culture) don't want to teach or learn a lot about nutrition. If you're not going to learn about the individual properties of a million single foods, "grouping" them is convenient and even helpful, but if you don't know the strengths and weaknesses of the grouping system, you can't use it appropriately.
The problem is we don't just simplify, we oversimplify to the point that much of the usefulness of the simplification is lost. And when you oversimplify, superstition also creeps in, because we tend to "fill in the blanks" with guesses and assumptions. People can easily confuse suggestions and guidelines with requirements and mandates.
I love exchange plan diets, because they're easy and provide built-in balance. I don't have to do the relatively simple (no trigonometry or calculus involved), but tedious math of looking at each in food's nutrients individually (I know there are online tools to do the math for me, but until I have an ipad or similar computer to take with me everywhere, I prefer using an easy sistem I can use anywhere).
I know that there's overlap and gaps within the exchanges, but the system is a useful way for me to program in variety and balance without doing more work (math, blegh).
I tend to go on food jags, so organizing foods into groups (exchanges use veggie, fruit, fat, protein, starch, and dairy) is convenient and useful.
When WW was an exchange plan, any food that contained at least 20% RDA of calcium could satisfy your dairy requirement (and if it contained more than 90 calories, you had to figure out which other food group exchanges were also satisfied). I wasn't a fan of milk, so I went out of my way looking for for those foods.
Not many people would think to count sardines as dairy, but I do (of course you have to eat the bones for it to count towards dairy). Because sardines also contain protein and fat, I have use the nutrition label to determine how many of each (dairy, protien, fat), so some math is unavoidable.
I also don't like that the FDA guidelines assume (and for the most part always have) that everyone needs the same nutrition - everyone's plate should look the same.
They don't specify the size of the plate, or how many meals ot have, so there's room for caloric differences, but that's it. No acknowledgement that some folks may need more protein, or less, more carbohydrates or less, more fat or less...
The one-size-fits-all approach is still assumed, and I don't think there is a one-size-fits-all approach, even when it comes to macronutrient percentages.
But as a science, nutrition lags behind the other sciences. Mostly (I beleive) because there's little profit in it. You can't turn it into a drug, and people generally don't want to pay for it (most people don't seek the help of a dietitian because insurance doesn't generally cover it).
Most doctors don't even get any training in nutrition or diet therapy. How can we say with a straight face "consult your doctor before beginning any program of diet or exercise," when doctors don't get any training on the subject. You might as well say "consult your mechanic."
Last edited by kaplods; 06-06-2011 at 04:40 PM.