Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New data validate the low-glycemic diet


A carefully controlled animal study provides clear evidence that a low-glycemic-index (low-GI) diet – one whose carbohydrates are low in sugar or release sugar slowly – can lead to weight loss, reduced body fat, and reduction in risk factors for diabetes and cardiovascular disease.

"The study findings should give impetus to large-scale trials of low-GI diets in humans," says senior author David Ludwig, MD, PhD, director of the Optimal Weight for Life (OWL) obesity program at Children’s Hospital Boston. His group’s findings appear in the August 28th issue of The Lancet.

Many studies, including small studies in humans, have suggested that low-GI diets are beneficial, but due to study design, the observed benefits could have come from other aspects of the subjects’ diets, such as fiber or overall caloric intake. For this reason, no major health agency or professional association references glycemic index in their dietary guidelines, Ludwig says.

In the current study, rats were fed tightly controlled diets with identical nutrients, except for the type of starch. Both diets were 69 percent carbohydrates, but 11 rats were randomly assigned to a high-GI starch and 10 to a low-GI starch. Food portions were controlled to maintain the same average body weight in the two groups.

At follow-up, the high-GI group had 71 percent more body fat and 8 percent less lean body mass than the low-GI group, despite very similar body weights. The fat in the high-GI group was concentrated in the trunk area, conferring "the apple shape as opposed to the pear shape," Ludwig says. (Having an apple shape is a known risk factor for cardiovascular disease in humans.)

The high-GI group also had significantly greater increases in blood glucose and insulin levels on an oral glucose tolerance test, and far more abnormalities in the pancreatic islet cells that make insulin, all changes that occur in diabetes. Finally, the high-GI group had blood triglyceride levels nearly three times that of the low-GI group, a risk factor for cardiovascular disease.

In a further experiment, rats were randomly assigned to one of the two diets, and, at week 7, were crossed over to the alternate diet for another 3 weeks. Rats that switched from a low to high GI diet showed greater increases in blood glucose and insulin than rats that were switched from high to low GI. Finally, 24 mice were randomly assigned to the low- or hi-GI diet. At week 9, the high-GI group had 93 percent more body fat than mice on the low-GI diet.

"What the study shows is that glycemic index is an independent factor that can have dramatic effects on the major chronic diseases plaguing developed nations – obesity, diabetes, and heart disease," says Ludwig. "This is the first study with hard endpoints that can definitively identify glycemic index as the active dietary factor."

Unlike the popular Atkins diet, which seeks to minimize carbohydrate intake, the low-GI diet makes distinctions among carbs. It avoids high glycemic-index foods, such as white bread, refined breakfast cereals, and concentrated sugars, which are rapidly digested and raise blood glucose and insulin to high levels. Instead, it emphasizes carbohydrates that release sugar more slowly, including whole grains, most fruits, vegetables, nuts, and legumes.

"The Atkins diet tries to get rid of all carbohydrates, which we think is excessively restrictive," says Ludwig. "You don’t have to go to this extreme if you pay attention to the glycemic index and choose low-GI carbs."

Bess Andrews | EurekAlert!
Further information:

More articles from Materials Sciences:

nachricht From ancient fossils to future cars
21.10.2016 | University of California - Riverside

nachricht Study explains strength gap between graphene, carbon fiber
20.10.2016 | Rice University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>