Hello Dsquared- you have to do 3 things to lose weight post-op: get your full allotment of protein, drink plenty of water and get some nutrition from real food. Watching calories is not what my doctor ordered. 600 calories can lead to malnutrition and slow your metabolism. Calories is a factor when looking at your height, weight and activity level. You might not feel like eating, but depending on the diet your nutritionist gave you, you should be. Check in with your doctor if your eating problems continue.