The perception is sometimes that health benefits require drastic changes to nutritional intake, and this can create a psychological barrier for those wishing to adhere to a higher quality diet. However, a number of studies have shown important health benefits from very simple and easy to implement, dietary changes. The glycaemic index (GI) of foods is increasingly being reported to play a role in the development of disorders of blood sugar, and reducing the GI of meals has been shown to cause beneficial changes to fasting blood sugar concentrations. Research published in the Journal of the American College of Nutrition in 20081 showed that incorporating one low GI meal per day, as breakfast, was successful at reducing the fasting blood glucose concentrations of the overweight or obese subjects. Importantly, these favourable changes occurred after just 21 days of consuming the low GI breakfast.
Using a randomised cross-over design study, the subjects received either a high or low GI breakfast for 21 days. The low GI breakfast comprised of 1/3 of a cup of bran cereal, 100mL skimmed milk, 1 slice of oat bran and honey, 1 tablespoon of reduced fat margarine, 2 dried apricots and ½ spoon of honey. The high GI breakfast comprised of 1 cup of corn flakes, 100mL low fat milk, 1 slice of whole meal bread, 1 tablespoon of margarine and 3-4 slices of banana. Both breakfasts provided similar energy, protein, fat and carbohydrate yields, but the low GI breakfast provided 9.92 g of fibre, compared to 3.18g for the high GI breakfast. The high and low GI breakfasts had values of 79 and 35, respectively, and this was reflected in the glycaemic loads which were 2960 (high GI) and 1455 (low GI).
The total daily intake of calories was not different between the low GI group and the high GI group. The satiety induced by the low GI breakfast was slightly higher than the high GI breakfast (7% versus 12%, respectively). This may be due to the additional fibre in the low GI diet, something that has been shown in previous studies investigating the satiety effect of fibre. However, not all studies show satiety effects from fibre and the effects are controversial, at least in the short-term. Longer term studies suggest that fibre is beneficial at inducing higher satiety values. Although beneficial effects of the low glycaemic breakfast were seen on fasting blood glucose, no significant changes occurred to blood lipids (high density lipoprotein, low density lipoprotein or triglycerides), insulin or body composition throughout the study period, suggesting that the study may have been of too short a duration.
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