July 21, 2007
Low Glycemic Index Diets Better For Weight Loss

A Cochrane Review meta-analysis of high and low glycemic index diets found that weight loss is greater and easier on low glycemic index diets.

Put aside the white bread and pick up an apple. A diet of foods less likely to spike blood sugar levels helps dieters lose more weight, according to a new systematic review from Australia.

“Losing weight is very difficult and many people are unable to sustain a weight-loss diet. The low glycemic index diet is satisfying and has proven benefits,” said review co-author Elizabeth Elliott, Ph.D., professor at the University of Sydney, The Children’s Hospital at Westmead.

It is disappointing that they could find only 6 suitable trials with a total of 202 adults.

Researchers evaluated randomized controlled trials that compared weight loss in people eating foods low on the glycemic index to weight loss in people on higher GI diets or other types of weight loss plans.

Six trials, involving 202 adults from Australia, France, South Africa, Denmark and the United States were included in the review. The diets lasted from five weeks to six months.

While the average low glycemic index dieter lost 2.2 pounds more the weight loss was even greater for obese dieters.

The review found that dieters focused on eating low GI foods dropped significantly more weight — about 2.2 pounds more — than participants on other diets. Low GI dieters also experienced greater decreases in body fat measurements and body mass index.

None of the studies reported adverse effects associated with consuming a low glycemic index diet.

“Compared to other diets, the low GI diet is more satisfying — people are less inclined to feel hungry. One advantage of this type of diet is that it is more likely to be maintained than other strict diets on which people feel hungry,” Elliott said.

Low glycemic diets appear to be effective even in obese people who need to lose considerable amounts of weight, the authors said.

In the two studies that evaluated only obese participants, low GI dieters lost about 9.2 pounds, compared with about 2.2 pounds shed by other dieters.

These results are not surprising. The higher blood sugar spikes after a meal the more insulin that pancreatic cells will release into the blood to bring it down. The insulin will make the blood sugar go down and all the food will get absorbed pretty quickly. Then you'll feel the need for more food.

High blood sugar spikes cause bad blood lipid profiles. So again it is not surprising that the lower glycemic index diets yield better blood cholesterol levels.

In the three studies that measured cardiovascular risk factors, people eating low GI foods experienced greater improvements in total blood cholesterol and low-density lipoprotein (LDL) — sometimes called “bad” cholesterol. High levels of total cholesterol and LDL cholesterol increase the risks for heart disease.

A professor at John Hopkins' public health school notes the paucity of good research on the weight effects of low glycemic index diets.

After reviewing the findings, Lawrence Cheskin, M.D. said, “There’s surprisingly little in the way of studies to draw any hard and fast conclusions.” Cheskin is director of the Johns Hopkins Weight Management Center and associate professor at Johns Hopkins Bloomberg School of Public Health in Baltimore. He was not involved with the review.

Most vegetables are very low glycemic index foods. But most people do not want to eat large quantities of vegetables every day.

Low glycemic index diets can be effective for weight management, Cheskin said, but the success of low glycemic diets lies with an individual’s willingness to comply with its nutritional principles.

“There aren’t many people who need to lose weight who are willing to eat lots of vegetables and whole grains. If they did, they wouldn’t have a weight problem in the first place,” Cheskin said.

A lot of people want to know what constitutes the ideal diet. The problem is that they've heard many times about the benefits of vegetables and filtered out that information as basically an unacceptable answer. They don't want to hear that the ideal diet involves eating 5 or 10 servings of vegetables each day. There aren't a few super high nutrient yummy foods that can substitute for low glycemic index vegetables. You have to eat more veggies.

Share |      Randall Parker, 2007 July 21 08:20 AM  Brain Appetite


Comments
Bob Badour said at July 21, 2007 8:49 AM:
The insulin will make the blood sugar go down and all the food will get absorbed pretty quickly.

Insulin is actually worse than you make it sound. Insulin stimulates fat cells to convert glucose into fat for storage and inhibits fat cells from releasing fats for fuel. After the insulin stimulated fat cells do their work, the brain has no fuel to run on. And what the brain wants, the brain gets. In this case, more fuel in the form of food.

M Younger said at July 23, 2007 1:51 PM:

"A lot of people want to know what constitutes the ideal diet. The problem is that they've heard many times about the benefits of vegetables and filtered out that information as basically an unacceptable answer. They don't want to hear that the ideal diet involves eating 5 or 10 servings of vegetables each day. There aren't a few super high nutrient yummy foods that can substitute for low glycemic index vegetables. You have to eat more veggies."

Right on - well put. The simplest and most straightforward solutions to fitness and a healthy diet are for the most part ignored by the general public. Advice such as "eat more broccoli" also gets the least promotion for the simple reason that there is far less potential for profit by peddling an unglamorous (and relatively inexpensive) regime of fruits, vegetables and regular exercise. Instead we have a never-ending supply of gadgets, books, DVDs, etc which have obviously had no effect on stopping the expansion of Americans' waistlines. It's almost comical to watch the masses (pun definitely intended) as they desperately try to keep up with an ever-changing set of easy answers for their weight problems that have been foisted upon them by charlatans, when the simple answer has always been right in front of them, both easy to comprehend, and best of all, FREE.

To your point, I think given that overweight adults who have spent decades forming poor eating habits and ignoring the obvious answers will be extremely reluctant to change their patterns on their own, our nation should concentrate on at least these three approaches to apply some external pressure on these peoples' habits:

1. make fruits and vegetables (not in the form of candy or drowning in cheese) far more readily available in peoples' daily lives, perhaps through subsidies or some other regulatory influence.
2. educate young children in school about healthy eating, as their parents, for the most part, haven't a clue what a healthy diet constitutes.
3. remove as much as possible the junk food your children (e.g., removing vending machines from schools and improving school lunches).

These are just some suggestions. If we don't do SOMETHING on a macro level to stem the tide of obesity, the USA (and seemingly much of the developed world) will eat itself into economic ruin as productivity declines and healthcare costs soar. Bon appetit!

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