I'm trying to get my head around something...

I know I need to take in 2000 calories a day to lose weight. To split the macro nutrients in thirds I would eat 166 grams of both protein and carbs per day and 74 grams of fat per day, right?

Well, the calories are equal, but there are more of them in a gram of fat (9) than in protein (4) or carbs (4). So, if we do the math, you'd be getting 1994 in equal parts.

not to mention alcohol is 7cals per gram, and insoluble fiber technically has no calories per gram

so...my math is wrong?

Slide rule math in the age of digital calculators!
The math is FINE!

Calories are always "equal"

They can be nothing else... a calorie is simply a unit of measurement.

Nutrient, now those vary. And that's where you're getting hung up.

Your best bet would be to determine a caloric intake based on your goals. Create a deficit for fat loss or a surplus for weight gain.

From there fill in what foods will comprise those calories starting with protein. A good idea would be to eat 1 gram of protein per pound. If you're carrying a lot of fat, use 1 gram of protein per pound of goal weight instead.

There are 4 calories in each gram of protein, so do the math to figure out how many calories you have left to fill.

Next I'd focus on fats. Fats should come primarily from the good stuff (monos and polys). Something like 25-30% of your total calories can come from fat as a foundation. There are 9 calories in each gram of fat.

Since you're just getting the hang of this, the rest of your calories can go to carbs. There are 4 calories in each gram of carb. This may need to be tweaked depending on your goals, response, etc.

To sum it up, suppose you weight 200 lbs and your goal is to lose some weight.

Your caloric goal might be something like 2000 calories.

Protein:

200 grams = 800 calories

Fat:

30% of 2000 = 600 calories = 70ish grams of fat

Carbs:

You still have 600 calories to work with (2000 - 800 - 600 = 600). That said, start with 150 grams of carbs and see how that pans out.

Nope, math is fine. Just saying a calorie has 1 calorie. It's the macronutrients that aren't equal.

Strout and DEF: word. A calorie is simply a unit of measurement, just like a kilogram or a liter. However the different macros contain different amounts of calories, and the body also treats the different macros differently, so how many of the calories in the macros your body will store or use as chemical energy (ATP) differs.

Awesome! Thanks a lot guys, I think I get it now. Soon I'll post my diet to get some suggestions.