1 October 2005

GI News Briefs

Just a Spoonful of Dressing …
One of the biggest challenges to losing weight is ignoring that gnawing feeling in your gut. Hunger. To date, more than 20 studies around the world have confirmed the remarkable fact that low GI foods, in comparison to their nutrient-matched high GI counterparts, are more filling, delay hunger pangs for longer, and/or reduce energy intake for the remainder of the day.

Now Swedish researchers report in the European Journal of Clinical Nutrition that vinegar (acetic acid) may also help dieters eat less and reduce cravings brought on by sugar spikes after meals. They found ‘a direct relationship between increased acetic acid and satiety’ according to the study’s lead author, Elin Ostman from Lund University. After an overnight fast, volunteers were given vinegar diluted in water with a portion of white bread containing 50 grams of available carbohydrates. The reference meal was bread without the vinegar. Satiety was measured on a subjective rating scale at 30, 90 and 120 minutes after the meal. The more vinegar they consumed (up to 2-3 tablespoons), the more satisfied the volunteers felt. Olstrom notes that the study could explain why some people feel a benefit of drinking a glass of vinegar and water before a meal.


—Reported in the European Journal of Clinical Nutrition (vol 59, issue 9, pp983−988)

Alternatively, try a spoonful of vinaigrette dressing (2 parts red or white vinegar to 1 part oil) with salad. It can lower the blood glucose response of a meal by up to 30 per cent according to Brand-Miller and her co-authors in The New Glucose Revolution.

Is There More to Fibre than Crunch?
A recent Danish study reported in Diabetes Care, the official journal of the American Diabetes Association, shows dietary fibre, but not the glycemic index, is important in prevention of insulin resistance.’ Using baseline data from the Danish population-based ‘Inter99 Study’, Catherine Lau and her team estimated dietary intake (total carbs, GI, GL, fibre and sucrose) from self-administered food frequency questionnaires of 5,675 non-diabetic Danish men and women aged between 30 and 60. They conclude that: ‘the present study does not support the hypothesis that habitual intake of diets with a high glycemic index and high glycemic load is associated with insulin resistance.’ They also point out that ‘intake of simple sugars in itself is not associated with an increased insulin resistance.’ However, the authors don’t give the reader any idea of the average in GI or GL in this population. It’s possible that the range is just too narrow. Their findings contrast with those of the Framingham Offspring Study reported in Diabetes Care in 2004.

—Reported in Diabetes Care, Volume 28, Number 6, June 2005

From Flab to Fab
‘When you lose weight through severely restricting your food intake, you lose some of your body’s muscle mass. Over the years this form of dieting will change your body composition to less muscle and proportionately more fat, making weight control increasingly difficult. Your body’s engine requires less and less energy to keep it ticking over. In fact it is sad but true that most people regain the weight they lost. A good diet does not require a lot of sacrifice or discipline—it’s sustainable over the long term because it’s enjoyable,’ say Brand-Miller and her co-authors in The Low GI Diet.

A reduced energy diet, the traditional treatment for obesity, has been only partially successful, write Austrian researchers in Diabetes, Obesity and Metabolism. Poor adherence long term and a significant loss of lean body mass resulting in a decrease of energy expenditure are contributing factors. Based on the growing body of evidence of the benefits of low GI carbs, the research team undertook a 24-week feasibility study to evaluate the effect on weight loss, body composition changes and dietary compliance of a low-fat diet with unrestricted low GI carbs. They found that combined with advice by a dietitian and bi-weekly one-hour group meetings, the low-fat, low-GI diet led to a significant reduction (-15%) of fat mass but only a small decrease in lean body mass (just -5%). Not only that, 109 of the 120 patients who took part stuck to the diet losing an average 8.9 kg (that’s around 370 grams a week on average). Lead author Babak Bahadori says that the diet may have benefited patients ‘by promoting satiety; and by promoting fat oxidation.’

—Reported in Diabetes, Obesity and Metabolism, 7, 2005, 290–293

Low Sat Fat + Low GI = Prevention of Heart Disease
Reduce blood sugar levels and you’ll reduce the risk of coronary heart disease say US researchers in Archives of Internal Medicine. According to lead author Elizabeth Selvin, ‘… lifestyle modifications, such as increased physical activity, weight loss and eating a healthful, low-glycaemic index diet rich in fibre, fruit and vegetables, may not only help prevent diabetes, but also reduce the risk of heart disease.’ The research team reports that elevated hemoglobin A1c—a measure of long-term blood glucose level that hovers between 4% and 6% in most people—is an independent risk factor for CHD even in those without diabetes. Their study was based on a prospective analysis of 1321 adults without diabetes and 1626 adults with diabetes from the Atherosclerosis Risk in Communities Study. Assessing the relationship between HbA1c level and CHD during 8 to 10 years of follow-up, they found that heart disease risk was almost doubled in people with HbA1c levels of 6 per cent or higher compared with people with an HbA1c level below 4.6 per cent.

—Reported in Archives of Internal Medicine, September 2005 (165, pp1910-1916).


Anonymous said...

When you mention having a glass of water with vinegar - is it white vinegar, red wine vinegar or apple cider vinegar?
I've never understood the difference between the three types.

GI Group said...

The important ingredient in vinegar whether it be white, red wine or apple cider vinegar is acetic acid. It is the acidity that lowers the GI of the meal by slowing gastric emptying.

For more information on vinegar and all the different types check it out on Wikipedia.