Best Weight Loss Systems

Please answer if you are good with Biology. A weight loss question?

I'm a nursing student and the following info I'm going to provide, I've learned it in my Nutrition class. It's been a while so my terminology isn't perfect. But you'll understand what I'm talking about. Take a girl, for example. Her body needs carbs (glucose) for energy. Okay. She gets that from food. When she stops eating, the glucose stored in muscle will be used up for energy then. When that's done, the stored glucose in the form of fat in her body will be used (in other words, the fat would be used up for energy). My question is, why is that a bad thing? Isn't that the way weight loss is supposed to work? I understand that once that stored fat is used up as well, the body will start breaking down muscle for energy. Why do people say that when you severly restrict your calories or stop eating altogether, after water weight loss, the first thing to go is muscle? Please understand that I am not anorexic. this is something I've been curious about for a while. Thank you for the great answers, everybody. And Carlos, there was nothing "retarded" about the question I asked. YOU don't even seem to UNDERSTAND what I asked.

Public Comments

1. Muscle is the first to go if you don't exercise as well. Basically the body stores fat easily but has to go to quite a lot of effort to break it down. When you diet or restrict your calorie intake in some way the first thing you break down for energy is stored carbs like starch. Then the body has to turn to another energy source. This *should* be fat... but it takes a while... this is why, about 1-2 weeks in to a diet so many people feel awful - they have run out of starch but the body has yet to start releasing energy from fat so they feel really hungry, weak and even faint. This is the point at which a lot of people give up! The body will break down muscle instead because muscle is primarily protein - also quite difficult to convert to energy but slightly easier than fat. The way to stop this is to exercise so that the body "realises" that the muscles are needed and fat is converted to energy instead. This is why all sensible diet plans recommend that you exercise as well.
2. well the thing is that the burning of fat is ketosis, which isnt a very healhty stage to keep your body in for a prolonged period of time. I don't know about th muscle part though.
3. you would lose muscle if you're not getting enough protein in your diet and if there's no exercise, then muscle isn't being used like it should be. That's why it's advised you exercise and weight train, so that your muscle is continuely used and actually weight training helps you to burn more calories.
4. Well its bad because you want to keep your muscles. Come on dont be retarded. Lets say some one is working out, they have built alot of muscle and its not defined cuz they are allitle bit fat. So in order to loose that fat they go on a diet, they will first have to loose all thier muslce, then they will start to loose fat. That is not fair cuz this person has worked really hard to get strong and build muscle. I think fat should go first that way people can stay stron and loose fat.
5. First of all when you stop eating to lose weight, your metabolism slows down so as to compensate for the lack of nutrients, thus glucose as well as fats and proteins will not be used up real quick and so you wont actually lose weight ( maybe 1kg or 2kg ). Cells are continuosly respiring in the body, they need glucose to do this, and so a conclusion can be made that the body needs a continuous supply of glucose ( This comes in Breakfast, Lunch, Dinner ), if you do not provide this, then these cells won't work efficiently. Fats are Stored Energy, they are needed when you exercise, 1 unit of fat provides 2X the amount of energy when compared to 1 unit of glucose. So fat is important during exercise and other physical activites, it is not meant to fuel you for the day. After Glucose and Fats have been depleted, the body will start to break down proteins for energy, thus they will go for the places where proteins are found in huge numbers, the muscles!. Thats why they say muscles are the first to go.
6. well, the body cant use ALL of the fat stored, becoz fat is used for maintaining healthy cells, in addition to other bodily functions... a category of fat is lipids which are imp for the various bodily functions.... and maintaining its level is imp, for there is a mechanism by the which the body realises that using any more fat will be dangerous (this comes from the survival instinct embedded in human genes)... therefore, it goes for the muscle and takes protein from the muscle to be used as energy source...
7. first of all, when you severally cut down on calories or stop eating entirely, your body goes into"starvation mode". meaning it saves fat and goes directly to using muscle. it'll save the fat as long as it can because there is more energy in the fat cells. then even if you loose twenty pounds when you start to eat again (even really healthy) your body is still in starvation mode and turns all the food you eat directly into fat. so you gain weight twice as fast as you did before. also you're not as strong since you've used muscle energy to live. just cut back slowly and with moderation so you don't go into starvation mode and you'll use up the fat. also there's always got to be exercise.
8. I'm a student of Molecular Biology and Biochemistry... and I can answer your question like this: When there is glucose restriction, lipid metabolism will take over to meet the energy demands. Lipid breakdown will produce Ketone bodies. Lipid metabolism will NOT result in production of glucose. The glyoxylate cycle doesn't operate in humans, and consequently, excess fats CANNOT be converted to carbohydrates. Ketone bodies can, however, serve as a source of ATP, and therefore function appropriately as energy sources for many tissues. BUT, certain tissues are absolutely dependent on glucose metabolism for energy (e.g, Red blood cells, kidney cells, brain cells etc...). Brain cells can shift their metabolic balance towards ketone body metabolism, but it usually requires about 72 hours for the brain to start using Ketone bodies. So, to produce Glucose, the body has available sources of protein in the muscle. These will breakdown to produce amino acids, some of which will be glucogenic... and lead to the production of glucose (by gluconeogenesis), that can be used by the RBCs, kidney, brain etc... This explains why... "the first thing to go after water weight loss is muscle".