**1.2 Carbohydrate**

Unlike amino acids, fatty acids, and many micronutrients, dietary carbohydrate is not required for survival. Although some cells, such as red blood cells, white blood cells, and some parts of the kidney, require glucose, the body can produce enough glucose to meet those needs. Despite the widespread belief that the brain can only run on glucose, the brain can run on both glucose and ketones [11]. When we do not eat a lot of carbs, our bodies have three options for getting energy:


Carbohydrate-restricted diets usually include some carbohydrates, but even if we eat no carbohydrates, our bodies will provide us with all the glucose and energy we require as long as we eat enough fat and protein. As a result, a well-planned, carbohydrate-restricted diet will provide all the nutrients needed.

#### **1.3 What is the difference between a glycemic index and a glycemic load?**

The ability of dietary carbohydrates to raise blood glucose levels varies greatly [13]. However, the carbohydrate density of each food is also a factor [14]. The glycemic index (GI) and glycemic load (GL) are terms used to describe these concepts.

When 50 grams of carbohydrate in watermelon are compared to 50 grams of carbohydrate in bananas, the carbohydrate in watermelon metabolizes quickly, resulting in a higher blood glucose response. As you can see, this indicates that its GI is higher. On the other hand, a banana has a much higher carbohydrate density than a watermelon. When similar serving sizes (120 grams of watermelon vs. 120 grams of banana) are compared, the serving of watermelon has a lower impact on blood sugar and thus has a lower GL.

The glycemic index response to food varies from person to person. The glycemic index of any given food can be influenced by the glycemic index of other foods eaten simultaneously [15]. The glycemic index is a good general guide, but the essential information is understanding how people react to specific foods (**Figure 1**).

#### **1.4 Different carbohydrate restriction levels**

Any dietary intervention that uses less than 130 grams of dietary carbohydrate per day is referred to as therapeutic carbohydrate restriction. The Dietary Reference Intake for the United States recommends this as the "minimum" level [11]. There are, however, various levels of carbohydrate restriction. The following definitions are used for better understanding:

• Ketogenic diets that are very low in carbohydrate — or keto diets — recommend no more than 20 grams of net dietary carbohydrate per day. The principles outlined in Dr. Atkins' New Diet Revolution are usually followed [17]. Other studies and protocols, such as those conducted by Virta Health, which you may have heard of, limit total dietary carbohydrates to 30 grams per day [18]. These two approaches will end up being very similar in practice. Almost everyone will experience a metabolic shift into nutritional ketosis due to both. The majority of patients find these diets to be incredibly filling. We advise patients to eat until they are satisfied rather than restricting or counting calories.

*Treating Type 2 Diabetes with Therapeutic Carbohydrate Restriction DOI: http://dx.doi.org/10.5772/intechopen.107184*


#### **Figure 1.**

*An infographic to show how the glycemic index helps inform dietary choices [16].*

