What is high glycemic (high sugar) food?

High Glycemic Foods: Definition and Health Implications

High glycemic foods are carbohydrate-rich foods that are rapidly digested and absorbed, causing a quick and significant rise in blood glucose levels. 1 These foods typically have a high glycemic index (GI) and glycemic load (GL), which measure the speed and magnitude of blood glucose elevation after consumption.

Characteristics of High Glycemic Foods

• High glycemic foods are typically highly refined, processed grain products with added sugars and low fiber content, as well as some starchy vegetables 1
• These foods produce brisk rises in blood glucose and insulin levels when consumed 1
• The conventional classification of simple (sugar) vs. complex (starch) carbohydrates has little physiologic relevance, as saccharide chain length has minimal influence on digestion rate or metabolic effects 1

Common Examples of High Glycemic Foods

• Refined grains: white bread, white rice, most breakfast cereals, crackers 1
• Starchy foods: russet or white potatoes 1
• Pure table sugar and added sugars 1
• Sugar-sweetened beverages (SSBs) 1
• Highly processed grain products with added sugars 1
• Boiled rice, white bread, pastry, honey, and sugar 2

Physiological Impact of High Glycemic Foods

• When starch enters the mouth without the natural protection of fiber or whole grain structure, oral amylase quickly begins breaking it down into glucose, a process completed rapidly in the small intestine 1
• This rapid digestion leads to quick glucose absorption and sharp increases in blood glucose and insulin levels 1
• Foods with a high glycemic index release glucose quickly, showing a rapid rise in blood glucose 1
• The glycemic response to food is influenced by the carbohydrate content, physical state (processed or whole, liquid or solid), and fiber content 1

Health Implications of High Glycemic Foods

• Rapid digestion of high glycemic foods may induce multiple adverse effects, including:

  • Stimulating reward/craving areas in the brain 1
  • Activating hepatic de novo lipogenesis (fat creation in the liver) 1
  • Increasing uric acid production 1
  • Promoting visceral adiposity (belly fat) 1
  • Potentially reducing total energy expenditure 1

• Poor quality carbohydrates like refined grains, certain potatoes, SSBs, and sweets are associated with:

  • Long-term weight gain 1
  • Increased risk of type 2 diabetes 1, 3
  • Higher cardiovascular disease risk 1, 3
  • Potential increased risk of endometrial cancer 1

• High sugar consumption, especially fructose, may promote glycation processes that can damage the glycocalyx (protective lining of blood vessels) 4

Contrasting with Low Glycemic Foods

• Low glycemic foods release glucose into the blood more slowly, with a lower overall peak in blood glucose over time 1
• Examples of low glycemic foods include:
  • Oats, barley, bulgur 1
  • Beans, lentils, legumes 1
  • Pasta 1
  • Pumpernickel (coarse rye) bread 1
  • Apples, oranges 1
  • Milk, yogurt 1
  • Foods high in fiber, fructose, lactose, or fat tend to lower glycemic response 1

Practical Considerations

• When choosing grain products, look for those with a ratio of total carbohydrate to dietary fiber of <10:1 as a practical guide to identify more healthful options 5
• Consider moderate carbohydrate intake (44-46% of total calories) as potentially more sustainable and safer long-term than very restrictive approaches 5
• Water should be emphasized as the primary beverage, with sweetened beverages (even those with non-nutritive sweeteners) reduced overall 5
• Replacing high-glycemic index carbohydrates with low-glycemic index forms may improve glycemic control in diabetic patients 3

Important Distinctions

• The glycemic load (GL) captures both the quality and quantity of carbohydrates consumed, giving a truer picture of how blood glucose is elevated in relation to specific food items 1
• While total carbohydrate consumption has little relation to cardiometabolic health, the quality of carbohydrate-rich foods is strongly linked to health risks 1
• Whole grains that are intact (e.g., quinoa) or partially intact (e.g., steel-cut oats) have lower glycemic responses than finely milled whole-grain products 1

Understanding high glycemic foods and their health implications can help guide dietary choices to support better blood glucose control and reduce risk of chronic diseases.