What's the rule to calculate the minimum you should be eating on a non fast day?
Have some concern as to eat enough on non fasting days, but not so much as to offset the weight loss effects of the fast.
Posted Nov 4, 2015, 3:06 AM UTC
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The easy way is to just eat normally when you're not fasting.
The more calculator-heavy method follows:
Goal bodyweight in lbs x 11 calories/day is where I would start. Nice good deficit. If you're fasting 2 days a week, you can then add these calories per day into the rest of your week.
So for example, I weigh 250 lbs and want to weigh 220.
Your weight in lbs x 11 calories/day/lb x 7 days gives the weekly intake. Then adjust your weekly intake by subtracting whatever your deficit is during your fast.
That's 2420 calories per day (220 x 11). I fast two days a week, so that's an additional 4840 calorie deficit. Divide that number by 5, the remaining (non-fasting) days per week gives you ~970. Then you can add that into your weekly calories - this gives 2420+970 or 3390 calories per non-fasting day. I still end up at a deficit week-to-week.
If you are doing a more mild fast, just adjust the numbers. So say I eat a 500 calorie dinner on each of my fasting days. Easy, you just subtract that from your middle number -- just subtract 1000 from your 4840 calorie deficit--this gives you about 770 calories a day additional, so 3190 calories.
Then make adjustments week-to-week depending on your rate of loss. Losing less than 1 lb/week? Cut 100 calories a day. Losing more than 2 lb/week? Add 100 calories a day. Losing between 1-2 lb per week? Don't touch anything, your plan is dialed-in.
Recheck the next week. Don't forget to get enough protein and lift weights. You want to protect your lean mass.
This took forever to explain, if you're confused I'll just make an excel spreadsheet.
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Thanks for that, you've given me a good starting point to play with some numbers. What I was seeking to prevent is eating too little on non fasting days.
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Basically as a general heuristic, if you are losing over 2 lbs/1 kg per week, you're going too fast (unless you are very fat to start with). The rate slows as you get leaner, but 1-2 lbs a week is optimal/sustainable for most people who aren't 25%+ bodyfat or under 12% bodyfat.
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My problem is that most weeks I am only losing .2 to .5 of a kilo so I want to make sure that I am not over or under eating during my non fasting days. Having said that I am happy with .5 of a kilo given that it's sustainable and that I seem to be building strength at the same time.
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In my world...if you eat less than 500 calories it is a fasting day. There is nothing inherently wrong with fasting for multiple days. Pay attention to your hunger, if you are hungry then eat. Of course I am assuming you are overweight and don't have an eating disorder.
I'm constantly hungry while fasting, actually seems like the closer I get to my target the hungrier I tend to feel, that and if I consume simple carbs the night before.
I was unclear on that. I meant on an EATING day eat only when you are hungry.