Carbohydrates22'23 are the body's main energy source; 50-55 per cent of the daily caloric intake should be provided by them. It is important that people with either type 1 or type 2 diabetes consume the right amount of carbohydrates, as they are the primary energy source for the central nervous system which depends on blood glucose. Carbohydrates also have the role of 'protein sparer', preventing the use of proteins for energy purposes, allowing them to perform their real role in tissue building and as metabolic primers for fat metabolism. The amount of carbohydrates in the diet regulates the levels of the intermediate products of fat metabolism, ketones. If the amount of carbohydrates is too low or unavailable, fat is oxidized for energy purposes with an increase of ketones
Diet and diabetes: prevention and control 131 Table 7.3 Classification of major dietary carbohydrates
Class (degree of polymerization)
Monosaccharides Disaccharides Malto-oligosaccharides Other oligosaccharides
Glucose, galactose, fructose Sucrose, lactose Maltodextrins
Raffinose, stachyose, fructo-oligosaccharides Amylose, amylopectine,
Non-starch polysaccharides modified starches
Cellulose, hemicelluloses, pectins, hydrocolloids resulting in keto-acidosis, which is a common problem in patients with type 1 diabetes.
From a biochemical point of view, carbohydrates are divided into three groups: sugars, oligosaccharides and polysaccharides (Table 7.3). According to the American Diabetes Association terms such as simple sugars, complex carbohydrates and fast-acting carbohydrates should be discarded as 'they are not well defined and should be avoided'.
Traditionally simple sugars were thought to be absorbed quickly, thus rapidly increasing the level of blood sugars and so were forbidden. However, the ADA Position Statement 2002 has concluded that for people with diabetes it is the total amount of carbohydrates in meals and snacks, rather than the type, that determines the glycaemic response. Sugars, however, should be restricted in the diet, as a high intake usually increases triglyceride levels in the blood and may also contribute to the development of dental caries. Moreover, sugars are usually associated with high-calorie foods, which should be limited in order to maintain a healthy body weight. Their amount should not be more than 10 per cent of the daily total energy intake. Polysaccharides are preferred, especially those containing fibre, since the more fibre food contains, the more slowly it is digested, raising blood sugar levels at a slower rate.
A system for classifying carbohydrates, known as the glycaemic index24 (Table 7.4), measures the effect that a food has on blood sugar levels. Foods that have a high glycaemic index cause a rapid and strong rise in blood sugar levels; diets filled with these foods have been linked to an increased risk for both diabetes and heart disease. Various factors, including the degree of processing, physical form and fibre content, determine a food's glycaemic index (Table 7.5).
Foods that contain complex carbohydrates, such as potatoes, quickly raise blood sugar levels, whereas foods that contain simple carbohydrates, such as whole fruit, raise blood sugar levels more slowly. However, the glycaemic index relates to the quality and not the quantity of carbohydrates consumed. Moreover, according to the ADA, 'although low glycaemic index foods may reduce postprandial hyperglycaemia, there is not sufficient evidence of long-term
Was this article helpful?
An Open Letter To Anyone Who Wants To Lose Up To 20 Pounds In 30 Days The 'Low Carb' Way. 30-Day Low Carb Diet 'Ketosis Plan' has already helped scores of people lose their excess pounds and inches faster and easier than they ever thought possible. Why not find out what 30-Day Low Carb Diet 'Ketosis Plan' can do for you by trying it out for yourself.