Glycemic Index

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Glycemic Index Glycemic LoadGoing for the 3
Increases Increase in Health, Increase in
Happiness Increase in Energy

• Strategies for Success in Weight Management
• By James J. Messina, Ph.D.

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Gylcemic Index GI

• A GI value tells you only how rapidly a
  particular carbohydrate turns into sugar
• Not all carbohydrates act the same
• Some are quickly broken down in the intestine,
  causing the blood sugar level to rise rapidly
• Such carbohydrates have a high glycemic index
  (GI).

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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 foods effect
  on blood sugar
• Calculating GL allows researchers to better
  relate carbohydrate intake to its health effects

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How to Calculate GL

• GL is amount of carbohydrate in serving of food
  multiplied by that foods 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).

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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

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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 doesnt have much
  carbohydrate, so its impact on blood sugar is
  much less than that of a serving of potato

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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

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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

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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

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How to use the GL in your food plans

• Knowing a foods 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

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How to use the GL in your food plans

• Substitute
• whole grain bread for white bread
• wild rice for white rice
• beans or lentils for potatoes
• Recognize that fruits non-starchy vegetables as
  well as whole grains beans, are rich in
  nutrients contain fiber, which slows digestion
  moderates blood sugar levels

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Online References on GI GL

• http//www.ajcn.org/cgi/content/abstract/71/6/1455
  
• http//archinte.ama-assn.org/issues/v161n4/abs/ioi
  00112.html
• http//www.glycemicindex.com/
• http//www.mendosa.com/gi.htm