text: Yo-yo dieting is very, very bad for you.  Like it was said above, it will slow down your metabolism.  When you starve yourself, your body begins to break down what energy stores it has to say alive.  Most people think that it is just eating up the stored fat they have and that is why they are losing weight.  THAT IS NOT TRUE!  \n\nThese trendy diets are all cleverly schemed ways to reduce your calorie intake and what usually happens is that you get so sick of their food that you quit eating all together.  This is NOT good.  \n\nWhen you starve yourself, your body breaks down the amino acids in your muscle and converts them into the compounds its needs to use glucose as energy.  So, you begin to loose weight and you think the diet is working.  But the diet is actually killing you.  Have you ever found that when you lose that weight your are urinating a lot?  That is because your body is getting rid of the Nitrogen that is found in the muscle's amino acids it is breaking down.  So your weight is going down, but you aren't losing any fat or getting much smaller.  Also, muscle tissue is what drives your metabolism, so if you lose your muscle tissue you are also losing your metabolism.  Remember, muscle weighs more than fat.\n\nThe only way to lose weight and not kill yourself is to cut your calories and increase your exercise.  Do something you like to do.  Run, walk, ride a bike, etc.  Eat healthy.  \n\nHow to figure out how many calories you need to eat a day:\n\n1- Take your weight and divide it by (2.2).  This will give you your weight in kg.  Then if you are a girl times it by 22 (guys multiply by 24).  This is how many calories your body needs to stay alive (breathing, your heart rate, etc).  Now I am guessing that you are a pretty sedentary person.  So multiply that number by 1.3.  This will give you how many calories you need to stay alive and move around every day.  Now take that number and multiply it by 7.  This will tell you how many calories you need in a week.  Now you can figure out how many calories you need to cut back to lose weight.  \n\n2- You should not lose more than 2 lbs per week.  If you are losing more than 2 lbs per week, you are probably losing muscle tissue and therefore actually slowing down your metabolism, not helping it.  \n\nYou need to eat 3500 calories less than you need to lose 1 lb of fat.  So take your total calories needed every week and subtract 3500 from it (7000 if you want to lose 2 lbs). Now divide that number by 7.  This will give you how many calories you should eat per day.  Now, you should NEVER EAT LESS THAN 1200 CALORIES PER DAY! This is just not healthy. \n\nTips to stay on your diet:\n\nEat a variety of foods, just watch your calories.  This way you do not get sick of the diet.  Plan your meals with a variety of LOW-CALORIE food.\n\nMake a shopping list, don't shop on an empty diet.\n\nAvoid alcohol.  Alcohol is high in calories and low in nutrition.\n\nOnly weigh yourself once a week, in the morning.  This way you are not freaking out the next morning when you haven't lost 5 lbs.\n\nKeep a daily record of what, where and how much you eat.\n\nAvoid midnight snacking like the plague.  You will still be alive in the morning.\n\nEat slowly.  It takes your body 20 minutes to realize it is full. One way to do this is to put down your fork in between bites.\n\nOnly eat in one room of the house.  That way your body is not conditioned to eat in the living room, bedroom, etc.  You will only get hungry when you go into the kitchen. \n\nPut your dinner on smaller plates so it will look like more food, and when you finish put your plate away so you are not tempted for seconds.  \n\nEat regularly, in the same place (nowhere else), and smaller meals.  This is so your body uses all the energy you put into and doesn't store any as fat.\n\nGood Luck!