I am on day 7 of fast …I want to do a 30 day but I read couple of bloggers saying there was barely any wt loss from day 21 to day 30. Kindly pour in your experience and help me decide…
I don’t have any studies to back me up, but I’d assume the weight loss would reduce as your body adapts, your metabolism would drop and would body would begin to burn less and less fat, however, it would still be relative to the amount of energy your body needs, thus, increased energy output would result in higher levels of weight loss. Also, the initial periods of weight loss, is from water loss in the muscles and so can give unrealistic weight loss that returns once fasting is ended.
I’m sure it makes a difference - that’s a 9 day delta. Your body needs energy just to sustain itself and if there’s no food coming in, that energy is going to continue to come from somewhere. And most of the science tells us that the vast majority will come from fat stores (unless there are none left.) during an extended fast.
For most people, fasting for one day is going to produce about half a pound of weight loss, based on a 2000 kcal TDEE (will be more or less for some people but just a rough average).
I’m sure metabolic adaptation could happen over the long haul to make the body more efficient at burning calories, lowering that \~2000 calorie number, but still, energy has to come from somewhere, especially if you’re still moving, breathing, pumping blood, walking, maintaining homeostasis for 9 extra days. I can’t fathom why a 30 day fast wouldn’t burn more fat than a 21 day fast just based on simple thermodynamics.
edit: any time I weight loss, I usually mean fat loss