People most often use the glycemic index to choose carbohydrate-containing
foods that will only minimally raise their blood sugar levels, with the intent
of preventing health problems associated with either high blood sugar or the
body’s reaction to rising blood sugar. These health problems may include
weight gain, diabetes, the insulin resistance
syndrome, hypoglycemia, and heart disease. Foods with a glycemic index of 55 and below are considered
ideal for those trying to consume low-glycemic-index foods.
Athletes may choose high-glycemic-index foods after intense exercise, in
order to rapidly replenish depleted carbohydrate stores.
What Do the Advocates Say?
The underlying premise for advocating eating low-glycemic-index foods is that
high-glycemic-index foods cause a rapid elevation in blood sugar that the body
attempts to balance by producing a large amount of insulin. Advocates claim
that human physiology is not designed to tolerate these rapid and prolonged
elevations in blood sugar and insulin caused by the prevalence of modern, high-glycemic-index
foods in the diet. As human civilization has evolved, primitive stone-age diets that
featured naturally occurring, low-carbohydrate foods have been replaced, first
by unprocessed but higher-carbohydrate agricultural foods such as whole grains
and legumes, and more recently by highly processed, low-fiber flours and other
starchy foods, plus an increasing amount of sweets. This trend towards higher-glycemic-index
foods in the diet is therefore deemed unnatural and hazardous to the healthy functioning
of the body.
Research suggests that repeated overproduction of insulin could lead to
insulin resistance, in which cells that normally respond to insulin become
less sensitive to its effects. Excessive high-glycemic-index foods, high insulin levels,
and insulin resistance have been associated with many health concerns,
including obesity, type 2
diabetes, heart disease, and some cancers. Changing
to a low-glycemic-index diet has been shown in most studies to reduce insulin
resistance, help control appetite, improve weight loss results, enhance blood
sugar control in diabetics, lower blood levels of total and LDL
("bad") cholesterol, and raise blood levels of HDL
What Do the Critics Say?
Critics say that the way the glycemic index is measured (one food at a time in
quantities that contain a standard amount of carbohydrate) does not resemble
the way people usually eat (many items are eaten together in varying portion
sizes, often mixing high-carbohydrate with low-carbohydrate foods). They also
criticize the complexity of the glycemic index concept and the fact that eating
large amounts of some low-glycemic-index foods, such as ice
cream, would be unhealthful due to the detrimental effects of other components of these foods,
such as animal fats. In the case of type 2 diabetes, critics point out that
the glycemic index only measures the short-term effects of foods on blood
sugar, whereas studies measuring longer-term effects of high-glycemic-index
foods in people with diabetes have found inconsistent results.
In answer to these criticisms, advocates point to the many studies linking
diets containing high-glycemic-index foods to common and serious health
problems. They insist that the diet can be made more healthful by integrating
the glycemic index with other health concepts, such as lowering animal fat
consumption, to achieve the best results.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2015.