The Glycemic Index and Weight Loss
When I first read about the glycemic index and weight loss in the early 1990's, it seemed to make perfect sense.
And being one of those people who have a tendency to obsess over small details, I invested a lot of time and effort in eliminating foods with a high GI from my diet.
Unfortunately, much of this effort was a complete waste of time.
It's not that there's anything wrong with following a diet that has a low
GI.
But if you make the same mistake that
a lot of people do, and focus ONLY on the glycemic index, chances are you'll
end up feeling frustrated because you're not losing any weight.
I'll explain why in a moment.
First, I want to take a closer look at a study that puts a low GI diet to the test.
Glycemic index weight loss
Researchers from the University of Minnesota wanted to find out if lowering the GI
of a diet already low in calories would have any further effect
on weight loss [1].
They compared the effects of three low-calorie diets,
each with a different glycemic load, on 29 obese adults. All of
the diets — high GI, low GI or high fat — provided
the same number of calories.
For the first 12 weeks, all food was provided to the subjects
(the feeding phase). Then, 22 subjects were told to follow
the assigned diet for an additional 24 weeks (the free-living
phase). After 12 weeks, all three groups lost weight. However, there
was no significant difference in weight loss between the groups.
Subjects on the low GI diet lost, on average, 21.8 pounds (9.9
kilograms), while those on the high GI diet lost 20.5 pounds (9.3
kilograms).
Weight changes between weeks 12 and 36 did not differ among groups. Those on the low GI diet lost an additional 4 pounds (1.8 kilograms), while those on the high GI diet lost 3.5 pounds (1.6 kilograms).
"In summary, lowering the glycemic load and glycemic index
of weight reduction diets does not provide any added benefit
to energy restriction in promoting weight loss in obese subjects," conclude
the researchers.
That's not to say that eating a diet with a low glycemic index won't help with weight loss, because it can.
But that's largely because many foods with a low glycemic index
(with the exception of high-fat foods like nuts and
avocados) also have a lower energy density.
In other words, when you eat fewer refined carbohydrates like cookies, cakes, or sweets and replace them with fruits, vegetables and protein-rich foods, you end
up eating fewer calories.
The result is that you lose weight.
In fact, if you follow the dietary guidelines outlined elsewhere on this site, you'll be eating a low GI diet without having to pay the slightest bit of attention to it.
Although its frequent appearance in newspapers and magazines
means that the GI will remain popular, it's my opinion that
it adds an unnecessary layer of complication to what is a relatively
simple process.
When it comes to losing weight, the secret to success
is still to consume fewer calories than you burn.
In fact, once the basics of your diet are in place, the source of the carbohydrate calories in your diet doesn't make a huge difference as far as weight loss is concerned.
Although the glycemic index can useful in some circumstances, it
was never meant to be used in isolation. Peanuts and avocados,
for example, have a very low glycemic index. But, they're also
high in calories. Eat too many of them, and you'll get fat.
About the Author
 My name is Christian Finn. I run a private "members only" website designed to help people burn fat, build muscle and get strong.
If you want accurate, honest and in-depth reviews on the latest "hot topics" in the world of fitness, you're confused by all the conflicting advice out there, or you just want some training routines that will give you better, faster results, click here now to learn more about how I can help you.
Related Articles
References
1. Raatz, S.K., Torkelson, C.J., Redmon, J.B., Reck, K.P., Kwong, C.A., Swanson,
J.E., Liu, C., Thomas, W., & Bantle, J.P. (2005). Reduced glycemic index
and glycemic load diets do not increase the effects of energy restriction
on weight loss and insulin sensitivity in obese men and women. Journal
of Nutrition, 135, 2387-2391
2. Sheard, N.F., Clark, N.G., Brand-Miller, J.C., Franz, M.J., Pi-Sunyer,
F.X., Mayer-Davis, E., Kulkarni, K., & Geil, P. (2004). Dietary carbohydrate
(amount and type) in the prevention and management of diabetes: a statement
by the american diabetes association. Diabetes
Care, 27, 2266-2271
3. Johnston, C.S., Day, C.S., & Swan, P,D. (2002). Postprandial thermogenesis
is increased 100% on a high-protein, low-fat diet versus a high-carbohydrate,
low-fat diet in healthy, young women. Journal
of the American College of Nutrition, 21, 55-61
|
| 
