GI Values Update

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What’s Cooking? And How?
Critics like to complain about the fact that the GI of a food can change with the way you cook it or prepare the food and the overall GI of a meal can vary depending on what you serve. But if they gave this a bit of thought, they would see that this is a plus (in more ways than one) and not a minus. It actually increases the number of foods we can eat and recipes we can enjoy that will keep our blood and insulin levels on an even keel. Not only that, food is more nutritious and delicious cooked and prepared the ‘low GI’ way (you haven’t boiled away all the goodness) or served with healthful ingredients that will help lower the overall GI of a meal (a jacket potato topped with baked beans, corn or chickpeas).

Let’s start with the ever-popular potato. As we said in last month’s GI News, boiled, mashed, steamed or fried, just about everybody loves potatoes. Unfortunately, a low GI variety of potato is hard to come by and it’s going to take a while for every variety of potato to be tested! The good news for potato lovers is that a potato salad made the day before, tossed with a vinaigrette dressing and kept in the fridge will have a much lower GI than potatoes served steaming hot from the pot. There are a couple of simple reasons for this. The cold storage increases the potatoes’ resistant starch content by more than a third and the acid in the vinaigrette whether you make it with lemon juice, lime juice or vinegar will slow stomach emptying. ‘That’s good news about eating acidic potato salad for us genetic potato lovers (i.e., Germans),’ said one of our regular readers. ‘One of our national dishes is (what is called in English) German Potato Salad. It’s made ahead of time with vinegar, carrots, garlic and bacon bits, and is available in many standard U.S. supermarkets.’ Another great ingredient to toss into a potato salad are crispy green beans just cooked al dente. But don’t go overboard, keep the portion size moderate!

photo: Scott Dickinson

What about pasta? Pasta in any shape or form has a relative low GI (30 to 60) but it needs to be cooked al dente (‘firm to the bite’). And this is the best way to eat pasta—it’s not meant to be soft. It should be slightly firm and offer some resistance when you are chewing it. Overcooking boosts the GI. Although most manufacturers specify a cooking time on the packet, don’t take their word for it. Start testing about 2–3 minutes before the indicated cooking time is up. But watch that glucose load. While al dente pasta is a low GI choice, eating too much will have a marked effect on your blood glucose. But a cup of al dente pasta combined with plenty of mixed vegetables and herbs can turn into three cups of a pasta-based meal and fits easily into any adult’s daily diet.


To lower the GI of a meal or recipe, simply add vinegar or lemon or lime juice to dressings, marinades or sauces. The effect appears to be related to the acidity, because other organic acids (such as lactic acid and propionic acid) also have a blood-glucose-lowering effect, but the degree of reduction varies with the type of acid. Essentially, the acidity in food puts the brake on stomach emptying, slowing the delivery of food to the small intestine. Digestion of the carbohydrate in the food is therefore slowed and the final result is that blood-glucose levels are significantly lower. And as we reported last month, Swedish researchers have found that vinegar may also help dieters eat less and reduce cravings brought on by sugar spikes after meals. The more vinegar consumed (up to 2–3 tablespoons before a meal), the more satisfied people felt.