What is the best way to eat? This can be different for each person depending on if you want to gain, lose, or maintain bodyweight. It also depends on the level of activity that you have on a daily basis, and your body fat percentage.

Bodyfat Percentage
The average female has approximately 30% bodyfat. The average male has approximately 20% bodyfat. An accurate measurment of your own bodyfat percentage can be obtained by having a skinfold caliper test, bioelectrical impedance test, or better yet a body bouyancy test performed. For the purposes of the following example, we'll use some "average" values.

Example: 130 lb female (moderately active)

130 x .30 = 39 lbs (fat weight)
130 - 39 = 91 lbs (lean body mass)

Activity Factor
Your activity factor is a value from 0.5 to 1.0 that is approximate for your level of daily activity. A sedentary person (couch potatoe) would have an activity level of 0.5. A moderately active person (someone who excercises 3 times per week for about 1 hour) would have an activity factor of 0.8. A very active person (competitive athlete, someone who trains daily) would have an activity level of 1.0. So, try to make a guess as to where you would fall within that spectrum. This activity factor will eventually help you get an idea how much of each of the Macro-Nutrients (fat, protein, carbs) you'll need. Now we can apply the value we obtained earlier...

91 lbs (lean body mass)
91 x 0.8 = 72 grams of protein

To figure out our carbohydrate and fat intake, we need to put our macronutrients into blocks:
1 block of protein equals 7 grams. (72 grams divided by 7 equals 10.2 blocks)
1 block of carbs equals 9 grams. (10.2 blocks multiplied by 9 equals 92 grams)
1 block of fat equals 1.5 grams. (10.2 blocks multiplied by 1.5 equals 15.3 grams)

So, to summarize: 72g Protein, 92g Carbs, and 15.3g Fat. Carbohydrate and fat intake may need to be adjusted for each individual.