Question about calories/exercise

I keep asking but not sure getting right answer.  Lets say you eat 1000 cal a day but you burn 500 in exercise are you to low in cals.  Im not losing weight and I wonder if this is starvation mode ???

First let me say I'm not a dietician.  But I can tell you my opinion based on research and personal experience.   Our bodies need a base amount of energy each to do it's thing - pump your heart, give your brain energy to think, liver and kidneys going, etc.  This is your base metabolic rate or your resting metabolic rate, commonly referred to as BMR or RMR.  If you're trying to maintain your weight, you need to eat enough calories to meet your BMR plus enough calories for whatever activity you do that day.   When you're trying to lose weight, you need to create a calorie deficit, meaning you burn more calories over the course of a day than you take in (on average).  If, however, you create too much of a calorie deficit, you're body may slow down your metabolism because it's not sure it will get enough energy to keep itself going long term.  This is what's often referred to as "starvation mode."   Most dieticians/nutritionists suggest a daily calorie deficit between 500-1000 calories to lose 1-2 pounds per week.  They also generally suggest that you do not go below 1200 calories per day.  If you're most than 1 year post-op, it's my opinion that these general numbers are a good measure for WLS folks as well.   So what do you do with that information?  First, use an online calculator to estimate your BMR.  This will give you a baseline for how much energy your body needs every day.  Keep in mind that this is just an estimate; your actual metabolic rate will vary based on how much you exercise, how much muscle you have, etc.  But's it a good yardstick.  Here's a link to an online calculator that I use: http://health.drgily.com/basal-metabolic-rate-calculator.php You may also want to read the page at wikipedia that discusses BMR (I found it interesting)... http://en.wikipedia.org/wiki/Metabolic_rate Then take your BMR, add the calories you are burning through exercise, and subtract between 500-1000 calories per day and that should give you a general number to aim for if you want to lose 1-2 pounds per week.   If you're eating 1000 calories a day and burning 500 through exercise and not losing, my educated guess is that your body needs more calories.  If you don't want to go through the process of calculating your BMR, etc., just try adding 100-200 calories per day to your routine and see what happens.  I'd bet you'll start losing again.... Good luck on your continuing journey -  Kellie

OMG, if you're burning 500 calories in your work-outs you will surely need more than 1000 calories a day. Most of us burn at least 1200 calories a day just existing. I am maintaining pretty well with lots of exercise and about 1700-1800 calories in an average day. The days I don't exercise as much, I don't get as hungry and don't need as many calories. If I'm a little more intense, I feel the need to eat more. Your body will probably tell you what it needs. 

Thank you both so much for your replys and I will check out the site you suggested. Thank you