Great question! This is one area that I have been doing a lot of reading on, as it was my main focus while I started to focus on my health/fitness.
There is a book worth reading, called "Burn the Fat, Feed the Muscle" by Tom Venuto. In the book he discusses caloric intake, and how to determine your needs.
I hope your alright with math... and forgive me if I over explain the topic, I would rather it be a little too simple than the opposite. This is what I use:
First, I had to find out what my body burns in a "at rest" state, called your BMI Basal Metabolic Rate
).
For men the formula is as follows:
BMR = 66 +
(13.7 * wt. in KG
) +
(5 * ht. in CM
) -
(6.8 * Age
)
For women the formula is:
BMR = 655 +
(9.6 X wt in kg
) +
(1.8 X ht in cm
) -
(4.7 X age in years
)
Again, this is just what your burn in daily functions. To find out a good estimate of what you burn based on activity, I had to find my TDEE orTotal Daily Energy Expenditure. This is your daily intake to maintain where you are at.
TDEE = activity level X BMI = calories/day
To find your activity level, choose from the list below:
Sedentary = BMR X 1.2
(little or no exercise, desk job
)
Lightly active = BMR X 1.375
(light exercise/sports 1-3 days/wk
)
Mod. active = BMR X 1.55
(moderate exercise/sports 3-5 days/wk
)
Very active = BMR X 1.725
(hard exercise/sports 6-7 days/wk
)
Extr. Active = BMR X 1.9
(hard daily exercise/sports & physical job or
2 X day training, marathon, football camp,contest, etc.
)
So if your BMI is 2000, and your very active, your equation would look like this:
TDEE = 1.725*2000 = 3450 calories/day.
I would suggest spreading that out equally over 5-6 meals a day. You could also taper it with the largest intake in the morning, and weaning off throughout the day.
Keep in mind, I am not a doctor, or professional. This is information I have found through research, and may not apply to everyone. This method isn't going to be perfect, but I have found it to give me a pretty good assumption. And yes, this is my disclaimer. lol.
I hope this helps!