Glycemic Load: Overrated?

Tufts University have just completed the first phase of a study comparing low-glycemic-load and high-glycemic-load diets.

The results show no significant difference after one year of weight loss.

The research used 34 overweight men and women. Calorie intake was restricted by 30%.

The Low GL diet consisted of 40% carbohydrate, 30% protein, 30% fat.
The High GL diet consisted of 60% carbohydrate, 20% protein, 20% fat.

Weight loss

Low GL groupHigh GL group
After 6 months 10% body weight9% body weight
After 12 months8% body weight8% body weight

This suggests that the Low-GL group had a greater tendency towards fat regain as time went on.

What makes this research more accurate than others is that it did not rely on self-reporting of food intake (which is usually fraught with error). The researchers were also able to determine if participants were engaging in "extra-curricular" eating.

Sources: Das, S.K. American Journal of Clinical Nutrition, April 2007; vol 85: pp 1023-1030, Tufts Press Release. See also Webmd.

More like this in Diets and Science · Apr 13, 2007

Comments

Quito on 04/13/07
From the Webmd article:

Low-carb diet advocates say people are more likely to stay on these diets because they provide more of the foods people like to eat. The study offers some support for this. During the first three months of the study, when subjects were most compliant with their diets, those in the high-glycemic-index group were less satisfied and had more desire for nondiet foods.

Yet by the end of the year, neither group ate more or less than the other. That may be because the researchers made an effort to ensure that the high-glycemic-index foods were as tasty and attractive as the low-glycemic-index foods.

"However, we did detect a greater tendency for weight and body-fat regain among low-glycemic-diet participants," Das said in a news release. "This finding suggests that reduced caloric intake may be harder to sustain on low-glycemic diets over time."

Perhaps these are indeed linked: going low-carb is easier intitially but also more likely to lead to calorie creep afterwards because of the smaller lifestyle change.Reply
Heather on 04/13/07

Thanks for the post

Reply
Passion for Health on 04/13/07

The study confirms the idea that it's calorie restriction that's the most important factor in weight loss. But the glycemic index isn't just about weight loss. High GI foods contribute to blood sugar disorders such as diabetes and insulin resistance.

The fact that the low GI folks felt more satisfied is almost certainly due to more steady blood sugar levels and probably better nutrition.

When you consider that almost all natural whole foods are medium or low GI, it all fits. The top of the GI chart are processed carbohydrates. Not stuff you want in your body anyway.
Cheers
Mike.

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Jim on 04/13/07
Passion for Health said:
But the glycemic index isn't just about weight loss[...]
In many ways the title of this post should read "Overrated for Fat Loss". GI was created as a tool for diabetics. In the last 2 years it's become a tool for weight loss: that is overrated.

Recently I read about research showing how the glycemic response changed depending on the fitness level of the person consuming the carbohydrate. Unfortunately I lost the link so cannot reproduce the source.

Endurance athletes would process carbohydrates far slower than a sedentary person. The implication of this is that the GI changed depending on the person!

Reply
Passion for Health on 04/13/07

Hi Jim, my feel is this...

If your diet is poor i.e. a typical western diet, insulin response becomes very trigger happy. As well as needing to react to spikes in blood sugar, the body's cells become "insulin resistant" and more insulin is needed to get the cells to take up the sugar.

Like you say overall health and fitness would play a big part too.. everything affects everything else no?

It takes a little while for the body to adjust to lower glycemic foods and for the pancreas to calm down.

The fact is that for millions of years, our genetics evolved in line with natural foods which are all low glycemic compared to the highly processed foods of today. When you consider that the majority of peoples carb intake is from these high GI foods, it's no wonder we have weight and health issues.

The high GI foods are a double wammy because they also tend to be low in nutrients per calorie.

Since calories per day is the limiting factor, folks eating processed foods are undernourished.

When dieting, obviously, we need to restrict calories which makes the business of making sure you get the most nutrients per calorie very important. Dieters should be especially vigilant to make sure they get loads of fruits and veggies in the diet.

Sorry to rant :) Don't know what came over me!
What say you?

Cheers
~Mike.

Reply
Lose Weight With Me on 04/13/07

I agree with Passion for Health. By watching the glycemic load of the foods I was eating I lost weight, yes, but I also went from border line diabetic to normal.

Brian

Reply
Passion for Health on 04/14/07

Nice work Brian... I like your blog too. Crazy list of goals WOW think big eh?? Let me know how you get on with those!! :)
Cheers
Mike.

Reply
Mar on 04/14/07

I don't care what one study does or does not say...it's all rather intuitive, I believe. Who here hasn't gone into a "sugar coma" after eating a few powdered sugar donuts (or whatever)? Eating a bowl of salad or beans doesn't ever make you feel bad. And who doesn't know that "the more sugar you eat, the more you want"?

I don't think life is worth living if you can't have a chocolate chip pecan cookie or sundae once in a while...but all these doritos and chips and crackers and pretzels and crap...constantly...everywhere we go... has certainly been the bane of my existence.

I do the elliptical 60 minutes a day, 5-6 days per week, and eat 15-1800 calories a day, yet have not lost one pound since mid January. I've never starved myself and my metabolism is not ruined, so this plateau really has me irked. I've been increasing my veggies lately, but starting Monday, I'm going to be a sugar nazi for a while, just to see if it makes a difference. (I'll post if it does.)

Reply
Lose Weight With Me on 04/14/07
Passion for Health said:
Nice work Brian... I like your blog too. Crazy list of goals WOW think big eh?? Let me know how you get on with those!! :) Cheers Mike.[...]

Hey, Mike, thanks for the kind words. I enjoy your blog as well.

As far as the goals...after quiting a 3-pack-a-day cigarette habit and losing nearly 70 pounds, I have come to believe that I can achieve any thing worthwhile that I set my mind on. So I don't want to sound cocky, but I plan to hit every one of those goals :-)

Brian

Reply
Passion for Health on 04/15/07

I believe in you Brian! GO GO GO :)

My Goal: Chill

Will I ever make it? Feels like such an uphill struggle :)
~Mike

Reply
Jarrett on 04/15/07

Don't you get tired of reading all of this crap? Calories in, calories out. That's all that's involved in weight loss. You can eat nothing but chocolate cake with fudge icing and lose weight as long as you expel more calories than you intake.

That might not be so healthy. No protein, pure sugar and fat. Whatever. It's not all about weight.

Whatever happened to just preparing your own meals from healthy, fresh foods, having a balanced diet, avoiding junk, and eating reasonable portions? Oh, that's right: real life.

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Quito on 04/15/07
Lose Weight With Me wrote:

As far as the goals...after quiting a 3-pack-a-day cigarette habit and losing nearly 70 pounds, I have come to believe that I can achieve any thing worthwhile that I set my mind on. So I don't want to sound cocky, but I plan to hit every one of those goals :-)

I just figured out that there were links here to people's personal pages. Brian, you're a force... I'm amazed, congratulations!

Your blog got me thinking about how the message is really changing the way one lives, which is hard by itself and made harder by the environment. This holds for overweight smokers and underweight teenagers. Reading your blog, though, I suspect you didn't just change your life; you reinvented yourself. How did you accommodate all of this with your family, your job, and your friends?

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Alex on 04/16/07

Since the study shows that there is no significant difference between low-glycemic-load and high-glycemic-load diet, we should be more concerned with the common factors of weight loss.

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jc on 04/16/07

Wow. Something like this seems pretty obvious. I'm glad they keep studying it though.

High / Low GI means nothing for weight loss. Calories are the defining factor. But most people can tell you that if you eat a bunch of refined carbs, you're blood sugar will crash a few hours later and feel starving again. At least thats what happens with me. This is not conducive to healthy weight loss (i don't think) as it encourages you to eat more calories.

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Sally on 04/16/07

The study clearly suggests that it makes no significant difference. So, we might as well stick with our own way of weight loss.
It's probably better if we just consult a doctor before considering this kind of diet.

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Lose Weight With Me on 04/17/07

Wow, Quito...thanks for your warm words. And you're right, it is more like reinventing myself. I am a completely different person than I was a year and a half ago.

As far as how I've accommodated it with friends, family, job, etc...I invented them to join me on the journey. I let them know that I'd love to have them along with me, but was OK if they didn't want to...as long as they didn't try to hold me back.

:-)

Thanks again

Brian

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jej on 04/18/07

don't you people know who they get these participants anyway?!? the pay isn't so great and i doubt any of these people stuck to their diets

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rhoda on 05/04/07

I am now trying to build muscle and lose fat, and lose net weight too. As dieting goes, I'm an innocent, but learning more all the time. It's confusing, isn't it? Well, going lower-GI has initially made me feel better. I have fewer mood swings and more skin comfort. I hope it lasts. But I wonder whether it's related to my trouble sleeping. i haven't been doing it long enough to tell. I just know sugar has been my source of energy for so many years that learning to live with less and get most of it from fresh fruits is exciting. If it doesn't help me lose weight, well, it can't hurt. And it makes me feel so much more stable in so many ways that I think it's worth it. Not only that, raising y protein level is good for my nerves. maybe I'm unusual, but these benefits are apparent to me.

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Michelle Sim on 11/05/07

In order to lose weight, how much GL do we need to take per day?

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Kailash on 11/06/07
Michelle Sim said:
In order to lose weight, how much GL do we need to take per day?

GL refers to "glycemic load". Foods can be high or low in GL, that is, the amount of insulin released when they are eaten.

Insulin is the hormone that directs the building of your body. So if you want to lose, you'll need to keep your insulin low, by eating a low GL diet.

Reply
Michelle Sim on 11/06/07

Thank you for your replied.
what I really wanted to know is with a low GL diet, the range must be not more than 10 right, then that is considered low?

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Steven on 12/12/07

GI has everything to do with weight loss.....high glycemic carbohydrates cause blood sugars to rise very rapidly, therefore causing the pancreas to release insulin very rapidly. In some people the body overcompensates and releases too much. The insulin will store these carbohydrates/sugars very quickly. The good side is you get a quick burst of energy; the bad side is most of what is eaten will be stored as fat. Since the blood sugars rose very rapidly, the insulin will try to bring the blood sugars within normal ranges very rapidly, causing the sugars to be pushed by the insulin into every cell, including fat cells. On the other hand, if you eat low-to-moderate glycemic carbohydrates, blood sugars rise more slowly; therefore so does insulin. When this happens more of what you ate is pushed into your body's cells to be used for energy, and whatever is left over will be stored in fat cells......so I would worry about GI if your trying to lose weight....

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Steven on 12/12/07

Part 2 most importantly: Insulin activates lipoprotein lipase. This enzyme acts as a roadblock for the removal of triglycerides (fat) out of the fat cells. Insulin also inhibits another enzyme called hormone sensitive lipase. This enzyme is responsible for the breaking down of stored fats, on your waist so to speak. During exercise if insulin levels are high, your body will use more energy from carbohydrates/sugars than from fat. Now you can see why most people see very little or no results in weight reduction, even though they exercise. The key is to control your insulin and blood sugars levels....

Reply

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