IF 5:2 and TDEE

kimberly_smith718
kimberly_smith718 Posts: 16
in Food and Nutrition
I am learning more about the 5:2 IF technique. If I want to lose weight (30 pounds), do I eat at my TDEE on my non-fast days, or at 80% of TDEE? I read in order to lose weight, you should deduct 20% from your TDEE. I was wondering if I have to do the deduction if I'm already doing 5:2. Also, what if I choose to do 16:8? Do the same requirements apply?

Replies

  • PatchEFog
    PatchEFog Posts: 152 Member
    Hi :) I don't do 5:2, but I have done JUDDD (Johnson's Up Day Down Day), which is similar (though they use two different calculations to obtain their BMR value: 5:2 uses Mifflin St-Jeor and JUDDD uses Harris Benedict), though can be 2 or three fasting days a week and has different percentages you can eat on those fasting days. Some people just can't fast like that and function, at least initially or have blood sugar issues that preclude them from doing a full zero calorie fast, even for a day.
    It would seem from the 5:2 website that you're going to get your caloric reduction from your 2 fasting days (where you eat a quarter of your normal calories) while you eat your normal calories on your 5 feeding/non-fasting days.
    The site I read is here: http://thefastdiet.co.uk/how-to-do-the-diet/
  • yarwell
    yarwell Posts: 10,477 Member
    5:2 is based on eating at maintenance for 5 days and 500 calories or so for 2 days.

    The deficit comes entirely from the 2 days.

    Average Deficit = TDEE - (5 * TDEE + 1000)/7 = TDEE * 2/7 - 143

    TDEE = 2000, deficit = 428 cals/day


    16:8 is just eating what you plan to eat within an 8 hour window, you eat the same cals each day and thereofre that has to have the deficit built in.
  • shabaity
    shabaity Posts: 792 Member
    16/8 works fairly well if your blood sugar can't sustain a 5/2 fast like mine. You still have to watch what you eat and eat in the deficit but its easier to eat in a deficit when you're only eating in a small window of time. In my case, it also had the added bonus of being a mood stabilizer as a bunch of little meals just leaves me being hungry and cranky.
  • angela233Z
    angela233Z Posts: 312 Member
    Kimberly

    are you planning to combine 5:2 and 16:8 or trying to decide between the two?

    I am doing 5:2, I eat 500 calories 2 days a week and TDEE ( or slightly over) the other 5 days a week. This averages out to about 20% lower than TDEE for the week and is working for me to lose weight.

    good luck

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