Surgeons and nutritionists recommending their patients to follow a low-carb diet can in many times lead to confusion. The most common question is always, “How many grams of carbs should I eat?” The simple answer is 100 to 130 grams per day. The follow-up question we get most of the time is then, “But I thought I was supposed to follow a low-carb diet. This seems like a lot!” To which our answer is: That amount would actually classify as a low-carb diet. Here is the reasoning:

Non-bariatric patients, those who have not undergone weight loss surgery, are recommended to eat around 300 grams of carbohydrates per day as part of a healthy 2,000-calorie diet. Because the size of the stomach of gastric sleeve patients has been reduced to a very small one, it is very challenging to eat enough food to hit that 2,000-calorie mark. Therefore, what is sacrificed in a gastric sleeve diet is in fact carbs.  Reducing that number to 100 to 130 grams per day already makes your diet a low-carb diet. Even though your stomach has shrunk significantly, your body still needs the same nutrients than a non-bariatric patient’s body. For example, you still need the same amount of vitamins and minerals, even though your sources might be slightly different (that is why it is recommended to take supplements; you can check out our supplement guide here). Eating too little carbs or avoiding them completely (which is almost impossible to do) will result in serious negative side effects that can affect your main body functions and metabolism. 

Following a Keto diet for example, which involves eating about 30 grams of carbs per day, argues that by cutting carbs you will force your body into Ketosis (1). What is Ketosis? It is a state where your body starts using your fat reserves as energy instead of carbs, mostly due to a low consumption of carbs and calories in general. Your body actually goes into Ketosis, during the initial stages of your recovery simply because your stomach is healing and you physically cannot consume enough calories.

However, if patients do not increase their calorie consumption to sustainable levels and add carbs back into their diets, they are almost guaranteed to experience negative side effects. These include:

  • Chronic fatigue

  • Irregular bowel movements (constipation)

  • Mood swings or being “hangry” (a natural response from your body for the lack of carbs)

  • Bad breath

  • Increased risk of cardiovascular disease from the likely overconsumption of saturated fat found in certain animal-based foods (meats and dairy)(2).

Cutting carbs to ultra low levels, like those advocated by a Keto or Atkins diet, can in fact result in dramatic weight loss. However, the weight loss is usually unsustainable (1,2). The reason is that by cutting carbs, you are actually depleting glycogen reserves in your liver, which are attached to a lot of water. As you deplete these, you lose the accompanying water and therefore a lot of weight. However, this is mostly water weight. As soon as you reintroduce carbs back into your diet your body will restore its glycogen reserves along with the water that goes with it, therefore causing you to regain weight. The initial weight loss is what actually makes patients think that carbs are bad, since by cutting them they saw some progress. But in reality, it is just an illusion that is bound to hit reality as soon as they reintroduce carbs back into their diet. The cycle is inevitable, therefore making ultra low-carb diets unsustainable.

We hope this article helped clear up some confusion around carbs and that you enjoyed reading it. Remember, as a premium member you can always contact our nutritionists with any additional questions.

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  1. DeNoon DJ. Low Carb Diets Work, but Safety Still an Issue. WebMD Website. Published September 2, 2004. Accessed July 30, 2018

  2. Calvo T. The Truth About Low Carb Diets for Weight Loss. Consumer Reports. Published January 17, 2018. Accessed August 2, 2018.