Glycemic Index & Glycemic LoadGoing for the 3 Increases: Increase in Health, Increase in

Happiness & Increase in Energy

Strategies for Success in Weight ManagementBy: James J. Messina, Ph.D.

Gylcemic Index – GI

A GI value tells you only how rapidly a particular carbohydrate turns into sugar

Not all carbohydrates act the sameSome are quickly broken down in the

intestine, causing the blood sugar level to rise rapidly

Such carbohydrates have a high glycemic index (GI).

Gylcemic Load - GL

Tells you how much of that carbohydrate is in a serving of a particular food

You need to know both the GI Gylcemic Index and the GL Gylcemic Load understand a food’s effect on blood sugar

Calculating GL allows researchers to better relate carbohydrate intake to its health effects

How to Calculate GL

GL is amount of carbohydrate in serving of food multiplied by that food’s GI

Glycemic load of a food is calculated by multiplying glycemic index times the carbohydrate content of food divided by 50g. (GI x CHO content of food / 50 g)

A 12 cup serving of carrots (which has 8 grams of carbohydrate) has a glycemic load of about 10 (8 * 131%, or 1.31 = 10.48).

Comparison of GL and GI

GI of a baked potato is 121% (assuming white bread is the standard reference food)

This has earned the potato, which is largely carbohydrate, a place on the “avoid” list in publications and on Web sites promoting the GI approach to food choices

Comparison of GL and GI

GI of carrots is high: 131%. But this unfavorable GI rating is based on the blood-sugar effect of eating 50 grams of carbohydrate from carrots — the amount contained in 1 ½ pounds — which few people would consume in one sitting

A serving of carrots doesn’t have much carbohydrate, so its impact on blood sugar is much less than that of a serving of potato

Comparison of GL and GI

Avoiding carrots because of their GI ranking would be a big mistake, particularly given all the vitamins and minerals they contain and the low GL of each serving

The GI of potatoes, on the other hand, is not a misleading measure because potatoes are carbohydrate-dense. Their GL is also fairly high

Research tells us to lower GL in diet

In American Journal of Clinical Nutrition (March 2001), Nurses’ Health Study researchers used blood samples & food-frequency questionnaire

Used GL measures to assess the impact of carbohydrate consumption on 280 postmenopausal women

Research tells us to lower GL in diet

High-GL diets (and, by extension, high GI foods and greater total carbohydrate intake), correlated with lower HDL concentrations and higher triglyceride levels, a marker for heart disease

Strongest association was in overweight women, i.e., those whose body mass index (BMI) was over 25. Increased risk started, on average, at a daily GL of 161

How to use the GL in your food plans

Knowing a food’s GL can help you make comparisons that can improve the quality of your carbohydrate choices

Good idea to replace processed and refined-grain carbohydrates, such as those found in many snacks and desserts, with fruits & non-starchy vegetables

How to use the GL in your food plans

Substitute:whole grain bread for white breadwild rice for white ricebeans or lentils for potatoesRecognize that fruits & non-starchy

vegetables as well as whole grains & beans, are rich in nutrients & contain fiber, which slows digestion & moderates blood sugar levels

Online References on GI & GL

http://www.ajcn.org/cgi/content/abstract/71/6/1455

http://archinte.ama-assn.org/issues/v161n4/abs/ioi00112.html

http://www.glycemicindex.com/ http://www.mendosa.com/gi.htm