Comment by keefe

Going from 4K-5K calories per day to 900 is an extreme swing. These type of diets are shown not to work. There is also some evidence they convince your body it is living in feast/famine time which triggers a fat accumulation response. I do not believe that it is healthy to remove carbohydrates from your body. The body is a complex machine indeed, but we have a pretty good understanding of how it works regarding nutrition. Most structures run on glucose, muscles are made of protein, fiber helps digestion and micronutrients are used all over the place. The bottom line is that fat is used for storing extra glucose. The function of protein in nutrition is very interesting. If you don't get enough, then your body will cannibalize muscles to get it. Proteins can be broken down to provide glucose, but it's inefficient and generates toxins. Carbohydrates break down to glucose much better. I would suggest you try a conventional approach : Checkout nutritiondata.com or one of the numerous calculators and for your weight and height calculate your daily needs. Pay particular attention to the grams of fiber needed and setup a plan that leads to 1-2lbs of fat loss per week - a deficit of only 500-1000 calories per day. Changing habits faster than that is generally not practical, it certainly never was for me. Make sure you are getting enough protein without overwhelming calories, supplementing with a protein shake if necessary. Try that out for half a year or a year with daily measurements and diet recalculation every 10 lbs lost. Never, ever deviate from the selected diet (you accomplish this by leaving wiggle room in your estimates), weigh yourself daily and keep careful records. I really don't think carb free living is either sustainable or healthy.