For whatever it’s worth, I am 74 years old, male, fairly fit with a full-time, active job that requires standing and walking (no sitting) during shifts. I find the following method for determining macros much easier to understand and utilize. It’s based on Bikman’s protein recommendation of approx 1.5 gr protein per KG of total body weight.
Total protein per day: 90 grams or 360 calories. This is 1.38 grams per kilogram of total body weight (144 lbs - 65.3 kg).
Total carbs per day: sub-17 grams or 70 calories max (I generally eat less, but use this number for calculating macros)
I need to eat 2800 calories per day to maintain weight (based on experience/testing):
2800 total calories - (360 calories protein + 70 calories carbs) = 2370 calories from fat
2370 / 9 = 263.3 grams of fat per day min.
THUS:
2.93 grams of fat per gram of protein
6.58 calories of fat per calorie of protein
OR in %:
85% Fat : 13% Protein : 3% carbs
The fat is a min value and the carbs a max value. I use the ratios 2.93:6.58::fat:protein in my daily meal spreadsheet to determine food portion amounts.
Hope this helps.