Strategies for Success in Weight Management By: James J. Messina, Ph.D.
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Transcript of Strategies for Success in Weight Management By: James J. Messina, Ph.D.
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