Yes as HJ said there are various apps for such things, but being the PH that I am I like to do it all myself n my spreadsheet brain. lol I like to know how to be my own app for those moments when I'm not digital.
So first of all I get my callipers out and pinch and inch or whatever and get a good estimate of the LBM (lean body mass) or the cells you would like to feed rather than just feeding all the jiggly bits you may not want.
So it looks like this as an example. 8 days Post fast I am 51.5kg and Im about 18% Body fat (BF) so 51.5 x .18=9.27BF take that away from me and Im left with 42.23kg LBM... If you are larger than you'd like to be just go by the weights/LBM your goal is....
Then we work out TEE (Total Energy Expenditure)
Then we need to feed that LBM, so we give it BMR (basal metabolic rate)- which is the calories it needs to survive if it were in a coma. The formulation I use is this as I find it to be the most accurate:
Katch-McArdle:Considered the most accurate for those who are relatively lean. Use if you have a good estimate of your bodyfat %.
BMR = 370 + (21.6 x LBM)Where LBM = [total weight (kg) x (100 - bodyfat %)]/100
so for me that is 370 +(21.6x42.23) =1282.16 BMR survival calories. (one wanting to loose massive weight need only eat their BMR)
We need to add in al of our whole lives activities, our exercise, training, walking, driving or anything that expends calories 24/7. So to do this we multiply by an activity variable depending on our lifestyle as follows:
1.2 = Sedentary (Desk job, and Little Formal Exercise)
1.3-1.4 = Lightly Active (Light daily activity AND light exercise 1-3 days a week)
1.5-1.6 = Moderately Active (Moderately daily Activity & Moderate exercise 3-5 days a week)
1.7-1.8 = Very Active (Physically demanding lifestyle & Hard exercise 6-7 days a week)
1.9-2.2 = Extremely Active (Athlete in ENDURANCE training or VERY HARD physical job
So for our worked example I would say post fast I'm pretty gentle with my workouts, so I will times my BMR by 1.2 which gives me 1,538.6 calories.
But wait theres more....
Then we need the TEF or the thermal effect of feeding or the calories we need to digest and mobilise our nutrients. This is irrespective of how many times/meals we break the total amount of food up into...
So for a mixed diet its around ~15%, for high protein its more like 25% but for us FAT lovers its as low as 5%, but I'm a bit generous and give about an 8% because I know my digestion works me pretty hard.
So multiply the 1,538.6 by .08 and we get 123.1so we add that and get 1661.7 calories per day... but what do we eat?
so we want to eat fat, carbs and protein. you can eat between 0.8-1.5g of protien per kg of LBM depending on your muscular demand - i go with 1g per LBM kg so thats around 42g protein... we multiply that by 4 to establish its caloric value which gives us 168calories of protein and 168/1661.7= 10.1% of total daily food intake for protein.
now carbs - i do not like to eat more than 60g per day max... again to establish caloric value we multiply the 60 by 4 and we get 240 calories per day of carbs. 240/1661.7= 14.5% of total daily food intake for carbs. This is the upper limit but I usually play it safe and have around 45g carbs which is only 10.8% for carbs daily but you give a little bit more for the just in cases!
NOW THE REST IS FAT so we say 1661.7 minus our protein cals 168, and minus our 180-240 carb cals and we get 1313.7 calories for just FAT.... we now DIVIDE by 9 as each g of fat is worth 9 calories and we get 146g of fat to consume each day.
I only track cals, carbs and fat and then at the end of the day I see if I managed to eat enough protein... The main thing is to get the carbs under... If i go over my cals but its only because of fat and not carbs then I don't really even care. but I just make sure the carbs are well below my limit.
I use an app called calorie king to check all my food macros as it lists all the au brands but I mainly eat unpacketed foods....
I do check my ketones on my ketosticks but they just expired and show me as level 4 out of 6 so I think they are had it now.
This seems like lots but i actually love it. I can still usually eat a small portion of fruit a day, and I just eat fat and its lovely.