Here we have meat, eggs and nuts.
Egg yolks are full of vitamins and minerals, egg whites have some protein. Since I was about 12, I've been aware of a trend (and I've been increasingly aware of it as an adult) in which people will have 1 egg + 6 egg whites in a meal. They throw away the yolks, usually, because the yolks contain fat and cholesterol, and not as much protein as the whites. When you consider that egg yolks contain the kind of fat and cholesterol you want in your body, and that they're almost like swallowing a mutli-vitamin capsule (perhaps even better, if we're to assume that vitamins work best in their natural state), you'll probably recognise this habit of ditching the yolks as madness...or at least the product of misinformation. Most of us would benefit from having an egg or two each day, and so long as it fits your macros/daily calories, I can't think of any reason for a healthy person to put a limit on how many eggs they should eat.
Meat includes the muscle mass of all animals that walk on land, fly in the sky and swim in the sea. Every time someone distinguishes between "meat" and "fish" or "poultry," I get an itch in the back of my brain that really wants to tell them that fish and poultry are meat. Anyway, meat is pretty much the best natural source of protein. The redder the meat, usually the more iron is in it, or so I've been lead to believe. Women need a boat load of iron, because every month they relieve themselves of a boat load of iron. Apparently long distance runners need a boat load of iron, too. So, if you're a female cardio bunny, you should probably be eating steak 24/7, give or take (not an actual prescription).
Om nom nom.
If you're reading this blog, then you probably have an interest in fitness, in particular strength, since that's where most of my attention has been spent so far. That being the case, it's worth knowing about macro-nutrient needs.
Sedentary people don't need much of any macro-nutrients. They aren't using their bodies, so they don't need a lot of carbohydrates for energy. They aren't putting wear and tear on their muscles, either, so they don't need a lot of protein. Sedentary people can often get away with consuming only 1g protein per kilogram of bodyweight. However, if you do train, and you train hard, you'll generally be wise to consume twice that much protein. That's 2g/kg/day. Sounds like meat's gonna be on the menu, in that case. 2-3 total serves of solid protein per day? Not a chance. Let's bump that up to the same standard we hold vegetables to: 3-5 servings, and possibly more. There also appear to be benefits to consuming 1g fat/kg/day. That's a bit more than "use sparingly," and a bit less than "pile it on in!" The rest of your macro-nutrients should probably be carbohydrates, and outside of the carbs found in fruit and vegetables, should generally be the kind that your taste buds don't recognise as sugar (although, at a chemical level, all carbohydrates are some combination of sugars). That brings us to...
Grains are, by and large, the most overrated item in the food pyramid. 6-11 servings? Seriously? Here's what grains provide: carbohydrates, more carbohydrates, satiety, and a poor source of protein. They don't provide much in the way of micro-nutrients, they just provide energy for doing stuff. Now, if you happen to have a physical job, then yeah, go ahead and eat 6-11 servings of grains a day. Are you a professional athlete? Go stuff your face with this stuff. Have as much as you need. Are you a white-collar professional who spends most of their time seated? Then put the sandwich down. Put the lasagne back in the freezer. Leave the rice alone. If you're trying to lose weight, you should probably be limiting yourself to 4 servings a day. Maintaining weight? 4-6. Gaining weight? 6+. That's right, I'm branding the prescription from the food pyramid that I was brought up on as weight gain territory for people who spend most of their time seated. And remember that I'm including sugars and high-carb vegetables in this category, too. So if you're mostly sedentary (except for when you hit the gym), trying to lose weight, and drinking a lot of coke and eating a lot of cake, guess what? You just wrote off your right to enjoy the satiation and more sustained energy release of more complex carbs. Good job.
Now, of course, these amounts need to be scaled based on the individual. Remember that grains are basically just filling in what's left of your macro-nutrients after you've had all your protein, fat, dairy, fruit and vegetables. Based on your current size and weight, your level of activity and your goals, how much carbohydrate your body needs will vary. In fact, this is probably the most variable part of a good eating plan, because it is the filler part.
I mentioned above that 1g fat/kg/day seems to work well. The fat you should be eating is generally the fat thatt's intuitively obvious where it came from. The fat on your meat is okay (but be sensible with how much of it you consume), the fat in your nuts and eggs is okay, olive oil is okay, the factory-made trans fats in more processed foods than you'd like to know about is probably not okay. There's been a lot of hating on saturated fats for as long as I've been alive, and an equal praise of unsaturated fats for a long time, too. The information I'm working with now seems to suggest that unsaturated (especially polyunsaturated) fats aren't all they've been cracked up to be, and saturated fats aren't as bad as they've been made out. Most sources I've dealt with regard factory-made trans fats to be poison.
The end bit
All in all, these are my thoughts. There is some study and experience behind this, but if you look you will find nutritionists, dieticians, personal trainers, and plenty of authors telling you otherwise. Take it or leave it. I feel that this covers the way most of us should be eating, but it's up to you to agree or disagree with me, and then to act on that sentiment.