Protein

Protein is what muscles are made of, so if you want muscles you have to eat protein just to make up for the amount that is destroyed throughout the day. Active people need a gram per pound of bodyweight per day for reasonable growth; bodybuilders need 20 gram more for optimum growth. Those numbers are controversial but it's what I follow. Ignore the US RDA on the label: that's the minimum amount necessary to prevent malnutrition diseases, not the optimal amount for growth. I said I "follow" this but I don't usually reach it. When I did try to chomp down 200 grams a day, I was force-feeding myself. 200 grams is a 50-gram protein shake when I wake up and go to sleep (100 total), six scrambled eggs for breakfast (54, or 154 total). That leaves only 50 to cover in lunch and dinner. The body can't absorb more than 50 grams per meal, but it needs protein every few hours or the metabolism will slow down, which inhibits both growth and fat loss.

Every week or two I go to Costco because the meat is both the most economical in bulk and the best quality. Turkey has the best protein/calorie ratio (even the pre-sliced lunchmeat!) and chicken is second, but I also get fish and other meats. Salami, cheese, and 5 dozen eggs are my Costco stables. (Along with bread, organic vegetables and cereal. Milk I get at the grocery store coz I can't drink the Costco size, and most vegetables I get at the Chinatown shops where it's much cheaper and you can get the Asian stuff.)

Eggs I fry in olive oil, six at a time, with a cover so the tops get cooked. Then I eat the whites and throw away the yolks (which are fat). That's easier than trying to separate liquid white from a jello yolk.

I use pretty simple protein powder, not the branched-chain special stuff unless it happens to be in the mix. Protein powder is usually made from whey and is universally disgusting and makes you want to puke, so you usually have to accept some sugar or other flavoring to keep from gagging. I've found the best way is to use chocolate rather than vanilla, look for a low-carb version, use a blender rather than stirring, put some ice in and crush it, and throw some excess juice in if you have recently-thawed blueberries around. If those aren't available, hold your breath and chug it and imagine you're at a frat party and your buddies are daring you to chug down the keg.

I used to eat protein bars but they have so much crap in them I don't anymore. But if it's a choice between eating that and something worse, well, OK.

So what do vegans do? I don't know. I was a semi-vegetarian until I decided to compromise with the devil for the sake of protein. I do know a couple vegetarian bodybuilders. But it's much harder to get protein solely from plant sources, so a supplement is pretty essential. I've also heard (though I haven't seen it confirmed elsewhere) that soy protein contains estrogens, which may hinder your progress. I doubt it's that much and I don't worry about soy sauce, but if you eat tofu every day it may be a concern. Fasting for religious reasons can retard progress even more, but that's the tradeoff.

There are moves afoot to change the laws to confuse the customer. One such attempt is to prohibit milk from being labelled "BGH free" (bovine growth hormone). This pales in comparison to cereal that's essentially candy, but it's a way to prevent health-conscious customers from knowing which milks are healthy. Speaking of BGH, I accidentally bought a container of milk that said "BGH free" and had a green environmentalist-friendly label and pictures of happy cows so it resembled the organic brands. After I took it home I discovered it only said that the milk was BGH free. All milk is BGH free. BGH is in the cows, not in the milk; it doesn't get passed through. It's added to raise the profit margin, not for the health of the cow.

Fat

First off, dietary fat does not equal body fat. The body can just as easily convert excess carbs and protein to body fat as it can dietary fat. Whether it does, or whether it allows the excess calories to pass out of the body unabsorbed, has mostly to do with insulin, which is produced to deal with carbohydrates (especially the ones in processed food), and which is what diabetics don't have. So don't worry about olive oil, butter or mayonnaise: your body knows what to do with them. Do worry about margarine, hydrogenated fat, and trans-fatty acids.

Certain fats are essential: flax oil (sold in a bottle and must be refrigerated) and Omega-3 fatty acids (found in salmon and to a lesser extent other fish). Some supplements like pro-hormones are fat soluble, meaning meaning eating flax oil along with them increases absorption.

Olive oil (extra virgin, cold pressed) is the most beneficial of the non-essential oils for may reasons. Greeks and Italians dip bread in olive oil every day, and put oil and vinegar on salads, and cook almost everything in olive oil, and they aren't fat. Some people put a tiny bit of olive oil on their face before sleeping to keep the skin healthy and fresh (men too!); it's much cheaper than commercial cosmetics, and is in fact what many of them contain anyway.

Beware of "light" or "fat-free" products. Ignore the fat level and instead compare the total calories, protein/calories ratio, and protein/carbs ratio.

As you switch your diet from carbs to fat, the body gets used to burning fat instead of carbs for energy, which supposedly makes it easier for the body to grab some stored body fat and burn it too, rather than demanding a carb intake (the carb craving).

Nuts are an often-overlooked good food. People forget about nuts because they're "high in fat", but hey, so what, they contain a lot of protein. Plus almonds taste good. Cashews, almonds, peanuts, Brazil nuts, and walnuts are my favorites. Mix them with raisins and chocolate chips and you have your own trail mix, much cheaper and more healthful than the commercial variety.

Spices are a good way to liven up plain food without fat.

Carbohydrates

There are two types of carbohydrates: clean carbs found in raw or lightly-cooked vegetables and whole grains, and dirty carbs found in "hydrogenated" or "saturated" oils, refined sugar, high-fructose corn syrup, white bread and other highly processed foods. The processing is done not for your benefit but to give the foods a longer shelf life and thus a higher profit margin. American society also skews food prices through farm subsidies. The farm subsidies were originally intended to prevent malnutrition, but now they end up making one of the worst fillers (corn syrup) cost essentially nothing, so producers use lots of it. Why not add corn syrup for nothing if it makes your product bigger or sweeter and thus generates a higher profit? "High-fructose corn syrup" is a sneaky lie because people see "fruct" (fruit) and "corn" and think it's healthy.

The reason to eat vegetables is for the vitamins. Remember the dark green ones. You can eat as much as you want because they're so low-calorie it doesn't matter. A glycemic index has not been established for many vegetables because the subjects would have to eat an insane amount (four pounds of sprouts in one meal or something like that) to get enough calories to do the measurement.

Fruits don't have quite as good vitamins/sugar ratio but they're a lot better than processed food. Gold's Gym did this marketing stint a few years ago, "Eat three apples a day, watch the pounds melt away". While this is hype there's a grain of truth in it. Apples have lots of fiber (like most vegetables and some fruits), so they fill you up and make you less likely to eat lesser-quality food, and the fiber is good for the digestion too. Plus apples are cheap relative to many foods, and they're easy to carry wherever you go.

With juice there are two things to worry about. Unless it says "100% juice" (in the US) it may only contain 10%. Apple juice and orange juice are normally pure, some others aren't. The other problem is that liquids present easy energy immediately; they don't require the body to expend energy breaking down the fruit. So juice tastes good and is convenient sometimes, but whole fruits are better.

What else is wrong with dirty carbs and even grains? They spike the blood sugar level sharply, requiring a large release of insulin to process. Clean carbs in contrast raise the blood sugar level slowly and manageably, so they don't require as much insulin. Insulin (that stuff diabetics don't have) encourages the body to store excess calories as fat. Plus the breakdown of white bread is essentially poison so it's bad for you (I can't believe Wonder Bread is so popular), and cleaning up the mess distracts the body from more important things like providing energy and building muscle mass.

There are certain other words to watch for, at least on US food labels. "Organic" and "natural" are pretty much trustworthy: I've never seen natural bread or a natural snack that had corn syrup and other oddities instead of sugar. Words like "modified" should raise alarm bells.