Glycemic Index and Glycemic Load

What is the effect on subsequent meals when the prior meal is low GL?

A low-GI meal leads to a lower glycemic response to subsequent meals as well.

What is the outcome of implementing a low GL diet on abdominal obesity, cholesterol, and glycemic control?

A study showed that implementation of a low-GL diet was associated with substantial, sustained improvements in abdominal obesity, cholesterol concentration, and glycemic control.

Compare the GI and GL of the following foods Bagel (white), Baguette (white), Rye-kernel (whole-grain pumpernickel), Wonder enriched white bread, Healthy choice Hearty 7-grain bread, pancakes, Lentils, raw strawberry, strawberry jam.

Bagel = 72/25 (GI/GL); Baguette = 95/15; Rye-kernel = 46/5; Wonder bread = 73/10; Healthy choice hearty 7-grain bread = 55/8; Pancakes = 67/39; Lentils = 22/4; Raw strawberry = 40/1; strawberry jam = 51/10

What is glycemic load (GL) and how it is different than GI?

GL accounts not only for how rapidly a food's carbohydrates are converted to glucose, but also the relative amounts of carbohydrate the food contains in an average serving.

What is the formula for calculating GL?

GL x number of grams of carbohydrates in a serving of the food / 100

What is the effect of high GL diets related to energy and fatigue?

High-GL foods can often lead to rapid release of large amounts of insulin, which can ultimately cause blood glucose levels to fall below fasting levels a few hours after eating. This rebound hypoglycemia can be characterized by fatigue.

Summarize the current understanding about the relationship between a low GL diet and inflammation.

Hyperglycemia has been found to increase the production of reactive oxygen species, which ultimately leads to inflammation. The exact mechanisms by which this occurs is unknown, but increased production of TNF-α may play a role. In contrast, diets low in GL and high in fiber may increase plasma adiponectin in diabetics, which is associated with better glycemic control and reduced inflammation in women.

What is the relationship between increases in GI and postprandial blood glucose and/or insulin levels?

In healthy individuals, stepwise increases in GI have been shown to predict stepwise elevations in postprandial blood glucose and insulin levels.

What is the association between the risk for type 2 diabetes, CVD, and certain cancers and the long term GL of a high GL diet?

Several studies have documented an independent association between long-term consumption of a high-GL diet and a higher risk for the development of type II diabetes, CVD, and certain cancers.

What are the 2 reference value foods used to compare a food of interest when referring to the glycemic index (GI), and why are they used? What value are the reference foods assigned?

They are glucose and white bread, which are assigned a value of 100 and they are used because they cause the fastest and most dramatic rise in glucose levels.

Use the offered example of the difference in GI and GL for watermelon (p.793) as an example to better appreciate how the concept affects blood glucose.

This example demonstrates that although foods with a low GI tend to have a low GL, foods with a high GI may vary as to whether they have a high or low GL. The GI of watermelon is high (72), since its carbohydrates are so rapidly converted to glucose. However, since watermelon contains relatively little carbohydrate content, it has a relatively low GL (4).

What affect does strict adherence to a Mediterranean diet have on CRP, IL-6, homocysteine, and fibrinogen levels as compared to individuals not on that diet (study of 3000 individuals in Greece)?

This study found that those who most strictly followed the Mediterranean diet had significantly lower levels of CRP, IL-6, homocysteine, and fibrinogen.

In a prospective study of 53,644 men and women, what was the effect on the risk of myocardial infarction when saturated fat was replaced with carbohydrates with a high GI? What was the effect when saturated fat was replaced by low GI carbohydrates?

When replaced with high-GI carbohydrates, the risk of MI was increased. Conversely, when replaced with low-GI carbohydrates, the risk of MI was decreased.

Is GL useful as a predictor of HDL levels in youth?

Yes, GL appears to be an important independent predictor of HDL cholesterol in youth.

What are the Practical Clinical Guidelines of the low GL diet?

• Increase consumption of fruits, vegetables, and legumes. • Consume fruits when they are underripe rather than overripe. • Consume grain products produced by traditional methods. • Avoid puffed grains and finely ground flour or grain products. • Acid in food lowers GI. • Limit intake of potatoes and concentrated sugars. • Consume high glycemic foods with fat and protein to reduce their GI. • In general, decrease consumption of "white foods" and increase that of multicolored, whole, nonprocessed foods.