The "MyPlate" was unveiled as the successor to the "Food Pyramid" and I was awaiting the usual fall-out of people saying what's wrong with it, but almost universally it was acclaimed as vastly superior in terms of design (which it is). It's meant to convey basic information in a very easily understandable way... and it works, for the most part:
If people take from this that half of their food should be fruits and vegetables, then maybe it's a good thing. The problem is that it is very easy to turn this plate into a nightmare of bad choices. One could say one's covered all the bases by a hot dog, white bread, pickle relish, Cheez-Whiz and a Fruit Roll-Up - but we all know without being told that that would be unhealthy.
The one person I heard that spoke against it was a physician who said that most of his patients (like him) were lactose-intolerant and diabetic, so he'd remove the dairy, increase the protein and vegetables and decrease the grains and fruit. Without saying as much, he was advocating a Paleo/Zone diet, which really is a good choice for lactose-intolerant diabetics.
I've written a fair bit about paleo and vegan diets here, because they've both become common among distance runners, though almost contradictory in their recommendations. They aren't weight-loss diets, but rather philosophical stances and it's the near-religious fervor of their adherents that bother me. A healthy paleo diet is a healthy diet. A healthy vegan diet is a healthy diet. The point I've tried to make is that, just because you follow some regimen, doesn't mean you're eating a healthy diet. I've known a vegan who lived on Pepsi and Fritos. I've known an obese follower of paleo who kept getting fatter (he saw it as an excuse to eat barbecue three times a day). I've also known world-class athletes who've followed one or the other plans.
Whenever one points out a problem with one of these regimens, there's usually a barrage of nasty "You just don't get it, you @#$% idiot! I have the facts from a reliable source" (which is usually some guy with a blog and an agenda). For example, followers of the paleo diet disagree about a lot of foods: tomatoes, yams, olives, alfalfa sprouts, bamboo shoots, beets. When you ask a vegan how they get vitamin B-12, you often get "it's over-rated; I've known people who ate vegan for years without thinking about B-12 and they're fine" or "take a certified vegan B-12 supplement. End of story." The scary thing is that there are vegans who glom onto anything that supports their cause; there was one report that detected B-12 in carrots and potatoes and ever since, there have been people who claim that if one eats those, one's okay, when in fact the test showed that the food was contaminated with fecal matter (which happens when you grow root vegetables in manure). Truly vegan natural sources of B-12 are all problematic - I have yet to find conclusive proof that wheat grass has any (and I've searched thousands of scientific documents); spirulina has some, but it also has a lot of related compounds that might interfere with absorption; chlorella is a good source, but has to be mechanically ground in a very precise way that's not regulated; nutritional yeast often has it because it's grown in a medium that contains it, but the original source comes into question; supplement pills work but suggest the whole plan is unnatural. Similarly, when you ask adherents of paleo diets how they get adequate amounts of some nutrients, they generally respond that all the scientific data is wrong and one doesn't really need as much as is generally recommended.
If you eat a diet that contains all the vitamins and minerals one needs in adequate amounts, has sufficient amounts of the essential amino acids and has some omega-3 and omega-6 fatty acids, how one gets them isn't terribly important, though natural sources contain a myriad of compounds that artificial ones do not (such as antioxidants). Nutrition is neutral at best; anything you can swallow that will make you a faster runner is a banned substance. If you get all the nutrients you need from natural sources, you'll be eating a healthy diet and then all that one needs to consider is balancing calories ingested with calories expended.
One of the more interesting regimens I've seen is attempting to eat only locally- and organically-grown food. Here in Minnesota, that will probably lead to a goiter, as there is zero iodine in the soil (the native tribes here must've eaten the thyroids of animals and a lot of eggs from migrating birds, to avoid deficiency). Just because you think your way of eating is ethical doesn't mean it's healthy.
Still, if you go to a multi-day race, you will see entrants who have fishing tackle boxes filled with pills and potions, coded for times of the day and for various conditions, such as swelled fingers or nausea. I once saw a friend of mine at the start of a 100 mile race swallow more than 100 pills: maltodextrin, branched-chain amino acids, glutamine, tyrosine, medium-chain triglycerides and fish oil capsules, a multivitamin, calcium, dozens of herbal supplements, caffeine, prescribed medications and over-the-counter pain killers. I asked him how he could tolerate that and he said all the pills made him constipated, so he added fiber supplements and they upset his stomach, so he took ginger capsules. Once you get on the pill bandwagon, it often snowballs like that.
The only advice I feel comfortable giving:
Eat real food. Eat when you're hungry and stop before you feel full. Try to make good choices 5 out of 6 (or 6 out of 7) times. Prepare your own meals and share them with others. If you're gaining weight, move more and try to eat smaller portions.