How much weight can you lose by not eating for a week?

• This is an ineffective way to lose weight, because you will not lose much fat, and you will put on fat more quickly when you restart your regular eating habits. If you want to lose fat, stop eating carbohydrate dense, processed foods. If it's in a box, carton or packet it's often bad. Stick to lean proteins, fruits and veggies and exercise often. You simply cannot lose weight and maintain your weight loss in the long run without changing your eating habits altogether.
• When your body stops getting food it goes into a starvation mode and saves fat. The weight you will lose (not much) will be mostly water and muscle tissue. This is bad because not only will you have to start eating again, but since you now have less muscle, and therefore a slower metabolism than when you began fasting, you will gain even more fat on top of the fat that your body stored while you fasted. The only time your body will start burning noticeable amounts of fat is when it can no longer burn muscle proteins as a fuel source. However, this will only happen you're close to death.
• Rather than starve yourself, you will do far better to strictly limit or eliminate (apart from the occasional treat) refined (processed) carbohydrates. If you are unsure what refined (processed) carbohydrates are, see the related link for a list. If you couple this will frequent, cardio exercise, you should lose weight.
• I tried it. I must say I do not have an addictive personality or focus much on my body or looks. I did it in an attempt to try to understand what a friend of mine was going through. I started at 176lbs and the initial weight loss was quick, probably due to emptying my body of the waste over the first couple of days. I drank only water and tea with milk and one sugar. I did my normal work involving moderate exercise and lost 11lbs. Unexpected symptoms nearing the 7th day were: flickering vision and problems focusing my eyes, giddiness, and fatigue. Please note: Half the weight was back on within a couple of days. Losing weight fast is not a viable method for people who need to lose weight, and is definitely very dangerous to people who want to lose only a bit of weight.
• You may lose a little bit of weight by starving yourself for a week because you body will become so hungry that it will start to eat fat and muscle tissue. You will likely also feel weak, tired, irritable, and sick because you are not consuming necessary calories or vitamins. This will also make your metabolism slow down, which will hinder current and future weight loss plans. After your fasting period, you are likely to gain much of the weight you may have lost back.
• Actually, if you starve yourself for long enough your metabolism will go into "starvation mode" and slow down. This is why many recovering anorexics gain more weight back than they originally had before the eating disorder.
• If you're really going to do the drastic, scary weight loss strategy, eat a small amount every day, divided into four or five small snacks. An intake of a small portion of food every few hours throughout the day will speed up your metabolism, and you should still lose weight in a very small amount of time because of the substantial decrease in calories.
• The real reason why people gain weight after fasting (starving) is because they go straight to heavy foods that requires a lot of chemical reactions to take place at once to break it down and your stomach just isn't used to that after starving it for prolonged periods of time. When you do start to eat its best to start of with small foods like soup and smoothies. Don't eat big meals. You have to let your body get used to eating again and exercise, but not extreme amounts, is recommended to keep the weight off.
  
• From personal experience, I would not recommend not eating anything. I went from 235 - 205 in the last month by sticking to the following meal plan: I don't eat breakfast. I eat a small cup of chunk light tuna (3 oz or so) for lunch and drink plenty of water throughout the day. I hit the gym and do plenty of cardio exercise (cardio exercise the key to major weight loss because it burns lots of fat). For dinner I have perhaps a cup of soup, a small piece of chicken, or nothing. No, its not healthy at all, but not eating anything is not very smart and is incredibly difficult to do. I have not felt fatigued, nor have I had any health problems of which I am aware.
• I would like to add that I drastically cut down on calories for around 2 weeks for my birthday party. I lost a stone (14 pounds) in 2 weeks and I actually still ate, just very little. I started eating again (not quite normally, but around 1500 calories a day) and I haven't gained any of it back at all. I'm really happy with my weight now, and eat three healthy meals a day, just small amounts each meal.
• If you're going to give up food for a week, try going on the Lemonade Diet; by going on the Lemonade Diet, your body won't be starved and you'll cleans your system. You can lose up to 20 pounds if you stay on the diet for 10 days.

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