3 months after sleeve gastrectomy, a patient of mine lost 65 pounds and so did her husband on whom I did not operate. My patient was on a typical post gastric sleeve diet consuming 900 calories a day with excellent appetite control. Her husband was similarly enjoying great satiety while consuming a high fat diet amounting to at least 2500 calories a day. He was following a ketogenic diet also known as keto diet. If you haven’t tried keto diet yet, you have most likely heard or read about it somewhere over the past 6 months. Keto diet that involves stopping carbohydrates and replacing them with natural fats like olive oil, avocado, grass fed meat and butter is quite a la mode these days. Excellent early weight loss results, supported by a number of studies, are one of the reasons behind its widespread acceptance.
Personally, I am not a fan of fad diets for quick weight loss purposes. I am a proponent of durable weight loss solutions like bariatric surgery. Bariatric surgery decreases appetite, reverses insulin resistance and decreases blood glucose. Interestingly, a ketogenic diet does the same. Bariatric surgery is effective and durable because it changes the interaction between ingested carbohydrates and gastro-intestinal tract. As a result of this new interaction, a number of gut hormone secretion, like GLP-1, is altered resulting in increased satiety and improved postprandial glucose metabolism. Ketogenic diet achieves the same purpose by significantly restricting carbohydrate intake, hence, bypassing a “faulty” glucose processing physiology. Let me explain.
Our modern, heavy on sugar and processed carbohydrates, diet has disrupted the delicate physiology of glucose metabolism. In the setting of a sedentary lifestyle, excessive sugar intake resulted in insulin resistance that favored fat accumulation leading to obesity. Bariatric surgery like sleeve gastrectomy, gastric bypass and duodenal switch is an effective weight loss tool because it alters hormones like GLP-1. GLP-1 plays a central role in glucose metabolism, satiety control and weight loss. Keto diet is similarly effective through a different mechanism of action. By replacing carbohydrates with fat, GLP-1 secretion is no longer needed to metabolize glucose. Indeed, a high fat diet impairs L cell secretion of GLP-1 because GLP-1 is not required in the setting of a high fat diet. Keto diet bypasses impaired GLP-1 secretion and bariatric surgery restores GLP-1 secretion. Both approaches result in significant and durable weight loss. Weight loss is durable with a keto diet because unlike a low-calorie diet, ketosis is associated with a high level of satiety. The brain is receiving plenty of energy in the form of ketones and does not induce an energy conservation mode. On the contrary, keto diet promotes breakdown of excess stored fat.
To summarize, in a state of insulin resistance, replacing glucose with fat to become the primary source of energy seems to be a good solution for weight loss. Ketosis like bariatric surgery achieves a state of low insulin, low glucose blood levels and increased satiety. In future blogs. I will go in more details about how to start keto diet, how to maintain weight loss on keto diet and I will share with you my personal experience with ketogenic diet.