Many people diet by avoiding fattening foods that taste good, but ultimately return to their regular eating habits. In research that sheds light on the perils of yo-yo dieting and repeated bouts of sugar bingeing, researchers from The Scripps Research Institute (TSRI) have shown in animal models that this type of diet cycling can activate the brain's stress system and generate overeating, anxiety and withdrawallike symptoms.
In the study, rats were divided into two groups. The first group was fed alternating cycles of five days of regular chow and two days of sweet chow. The second group ate only regular chow. The amount of food consumed was not restricted for either group.
The two groups showed different patterns of behavior with the diet-cycled rodents fed regular chow putting less effort into obtaining the previously acceptable food. Thus, they ate less and were more likely to avoid anxiety-provoking situations. When returned to a diet of sweet food, their anxiety-related behaviors returned to normal, but they ate more than they needed.
This suggests that frequent dieting with frequent relapse is worse than dieting by itself. The research is reported in the journal Proceedings of the National Academy of Sciences (PNAS). http://bit.ly/12yxdI.
Mummies and heart disease
A new study finds that atherosclerosis (hardening of the arteries) was common in ancient Egyptians, challenging a belief that vascular disease is a modern affliction caused by current-day stress and sedentary lifestyles.
Michael Miyamoto, M.D., a graduate of the UCSD School of Medicine and assistant clinical professor, and a team of cardiologists and Egyptologists examined 22 mummies from the Museum of Egyptian Antiquities using a six-slice CT scanner. In the mummies with identifiable arteries, more than half displayed calcifications, and those who died after the age of 45 showed the highest degree of calcification. Vascular disease was observed in both male and female mummies.
Surprised by their results, the cardiologists sought information on the lifestyle of ancient Egypt. Dietwise, eating beef, duck and other poultry was common with salt widely used for meat preservation. Tobacco was not available in that era and without mechanical transportation, all were likely physically active during their lifetime.
Results of the study appear in the Journal of the American Medical Association. http://bit.ly/1H546u.
Web archives developed
UCSD librarians are part of a collaborative effort to build a series of Web archives on critical subjects such as the swine flu epidemic and the devastating California wildfires of 2007. The archives use a new web Archiving Service (WAS) developed by the UC's California Digital Library (CDL), which has enabled librarians to capture, curate and preserve Web sites for the benefit of researchers and the general public.
The WAS allows scholars and other users to access, search and analyze the contents of archives in ways they could not on the live web. The archives are necessary because Web sites routinely change, move or disappear with little or no notice putting important information at risk unless steps are taken to preserve it. To date, the effort has produced 21 Web archives, which include approximately 1,020 Web sites, nearly 68 million documents, and 4.2 terabytes of data.
Lynne Friedmann is a science writer based in Solana Beach.