However, the observation that normalization of glucose in type 2 diabetes occurred within days after bariatric surgery, before substantial weight loss (15), led to the widespread belief that surgery itself brought about specific changes mediated through incretin hormone secretion (16,17). This reasoning overlooked the major change that follows bariatric surgery: an acute, profound decrease in calorie intake. Typically, those undergoing bariatric surgery have a mean body weight of ∼150 kg (15) and would therefore require a daily calorie intake of ∼13.4 MJ/day (3,200 kcal/day) for weight maintenance (18). This intake decreases precipitously at the time of surgery. The sudden reversal of traffic into fat stores brings about a profound change in intracellular concentration of fat metabolites. It is known that under hypocaloric conditions, fat is mobilized first from the liver and other ectopic sites rather than from visceral or subcutaneous fat stores (19). This process has been studied in detail during more moderate calorie restriction in type 2 diabetes over 8 weeks (20). Fasting plasma glucose was shown to be improved because of an 81% decrease in liver fat content and normalization of hepatic insulin sensitivity with no change in the insulin resistance of muscle.
A healthy balance of carbohydrates, proteins, and fats in your diet will help keep your blood glucose on target. How much of each will depend on many factors, including your weight and your personal preferences. Watching your carbohydrates -- knowing how much you need and how many you are eating -- is key to blood sugar control. If you are overweight, either a low-carbohydrate, low-fat/low calorie, or Mediterranean diet may help you get your weight to goal. No more than 7% of your diet should come from saturated fat, and you should try to avoid trans fats altogether.
High blood sugar (hyperglycemia). Your blood sugar level can rise for many reasons, including eating too much, being sick or not taking enough glucose-lowering medication. Check your blood sugar level often, and watch for signs and symptoms of high blood sugar — frequent urination, increased thirst, dry mouth, blurred vision, fatigue and nausea. If you have hyperglycemia, you'll need to adjust your meal plan, medications or both.