Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New data validate the low-glycemic diet

27.08.2004


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:
http://www.harvard.edu
http://www.childrenshospital.org

More articles from Materials Sciences:

nachricht Beyond conventional solution-process for 2-D heterostructure
22.06.2018 | Science China Press

nachricht Graphene assembled film shows higher thermal conductivity than graphite film
22.06.2018 | Chalmers University of Technology

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>