Hi Aby, Re. your body fat percentage question.
I have done this exam to find out my body fat about 5 times. I either do it with my nutrologist or with a personal trainer to find out. Please note that this is not regarding BMI (which stands for body mass)...you can find out if your body mass is within the correct range online by entering your height and weight. But for body fat percentage and a detailed report on body composition you need other info, thus the reason I go check it with a professional.
The correct range of body fat percentage varies from person-to-person based on a number of factors. Such as age, body structure, overall health, fitness level, diet and activity performed, etc. Many professionals will consider the body fat percentage a more important number than the body mass index. That's because of the details an exam with body fat percentage can provide about the patient.
For example, I was at 13% of body fat after doing 40days of clean-portion controlled eating (I decreased sugar consumption A LOT during this period)...when I went for my exam I was at 57kg...but here is the BIGGEST DIFFERENCE...when I did this same exam back in the day, I weighed at 58kg - just 1kg above - I was working out regularly and eating normally (no extremes - healthy and unhealthy food mixed and no portion control) and my body fat percentage was 22%.
Now, 22% is considered healthy for a female my age, height, and weight, but the percentage was WAY higher compared to now, likely due to changes I made in my diet.
I don't think there is an specific time to do the exam, I know the professional can do it manually, but I did it in a machine...using the machine I had my clothes on, had it done in the afternoon (after breakfast/lunch) and it still gives you an accurate measure. Specially because it's not 1 meal that will make the difference, if you are eating healthy it will show, and if you are eating unhealthy it will show too...this is about overall fat inside of you, not WEIGHT!
The exam detects all body composition, including places where fat is most likely to storage and what areas need work. When I lose weight, it shows right away on my upper body (waist up), so my doctor asked me to lift weights in order to get more mass in there bc I am too skinny in this area and need better support........whereas on my problem areas (thighs and glutes) there still has a higher concentration of water/fat retention. Overall, I don't want to decrease my body percentage anymore because your body needs a minimum of 8-11% for an emergency...but going from healthy to athlete range made me very happy since I did put a lot of work both on fitness and on improving my diet. I also regularly have a fitness activity that requires me on a lower range (running, doing 5-10k and marathons)...depending on what fitness activity you target, you may need a higher percentage to store on energy.
Check in your area where you can get that exam/report done...it's painless and it gives you a good idea on what you are working with. Online doesn't offer a detailed report as a professional, specially because it doesn't take into consideration overall health and body composition. But here is a rough prospect of what it's said about appropriate fat percentage.
Acceptable Body Fat Percentage
Description Female
Essential Fat 10-12%
Athletes 14-20%
Fitness 21-24%
Acceptable 25-30%
Obese 31%+
and here is another link about it:
http://www.humankinetics.com/excerpts/excerpts/normal-ranges-of-body-weight-and-body-fat