Would fasting for 3 days start the body healing itself and weight loss ?

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A three day fast does not do anything to help the body initiate healing, and starving the body for three days does not increase the chances of a successful weight loss program. To achieve true weight loss requires long-term change in dietary habits. Contact your primary care doctor to discuss this, perhaps with a referral to a nutritionist. Weight loss can be great for you! Congratulations.