According to the World Health Organization (WHO), 63 percent of the deaths that occurred in 2008 were attributed to non-communicable chronic diseases such as cardiovascular disease, certain cancers, Type 2 diabetes and obesity — for which poor diets are contributing factors. Yet people that live in societies that eat healthy, plant-based diets rarely fall victim to these ailments. Continue reading
Even though the study participants ate whatever they wanted on their non-fasting days, they lost an average of 5.6 kilograms (about 12 pounds) after eight weeks,
What’s more, their total and “bad” LDL cholesterol levels dropped, and their blood pressure fell.
“People lost anywhere from about 7 pounds to about 30 pounds and that was in a very short amount of time,” Varady said. And, she added, the program was pretty easy for the study participants to follow.
People typically try to lose weight by cutting their calorie intake every day, Varady and her team note in the American Journal of Clinical Nutrition. A much rarer approach, they add, is to have people alternate “feed days” with “fast days.” Studies in normal and overweight people have shown that this strategy can indeed help people lose weight and improve their cholesterol levels.
To test alternate-day fasting in obese adults, Varady and her colleagues had 12 obese women and 4 obese men begin by eating normally for a two-week control period. Then, for eight weeks, they ate just 25 percent of the calories they needed to maintain their weight, between noon and 2 p.m., every other day.
For the first four weeks, the researchers provided study participants with their fasting day meal, while for the next four, study participants met with a dietitian every week and prepared the meal themselves.
Study participants lost about 0.7 kilograms (1.5 pounds) every week. At the end of the eight-week diet, their total cholesterol had dropped by 21 percent, on average, while their LDL cholesterol had dropped 25 percent. Moreover, their systolic blood pressure (the upper number in a blood pressure reading) had fallen by an average of five points.
While Varady and her team had thought people might overeat on their non-fasting day in order to compensate, this turned out not to be true; people typically ate between 100 percent or 125 percent of their calorie needs on their all-you-can eat days.
“I think it’s probably because their stomachs kind of shrunk,” she said.
The next step, the researcher said, will be to figure out if people can maintain the on-off approach for a longer period of time, to continue to lose weight or to maintain a healthy weight.
Anyone who wants to give the diet a try, she added, should meet with their doctor or a dietitian first.
SOURCE: American Journal of Clinical Nutrition, November 2009.
How Some People Maintain Weight Loss, Others Don’t
The researchers showed that when individuals who had kept the weight off for several years were shown pictures of food, they were more likely to engage the areas of the brain associated with behavioral control and visual attention, as compared to obese and normal weight participants.
The findings of the study suggest that successful weight loss maintainers may learn to respond differently to food cues.
“Our findings shed some light on the biological factors that may contribute to weight loss maintenance. They also provide an intriguing complement to previous behavioral studies that suggest people who have maintained a long-term weight loss monitor their food intake closely and exhibit restraint in their food choices,” said lead author
Long-term weight loss maintenance continues to be a major problem in obesity treatment.
Participants in behavioral weight loss programs lose an average of 8 to 10 percent of their weight during the first six months of treatment, and will maintain approximately two-thirds of their weight loss after one year.
However, despite intensive efforts, weight regain appears to continue for the next several years, with most patients returning to their baseline weight after five years.
The researchers used functional magnetic resource imaging (fMRI) to study the brain activity of three groups- 18 individuals of normal weight, 16 obese individuals (defined as a body mass index of at least 30), and 17 participants who have lost at least 30 lbs and have successfully maintained that weight loss for a minimum of three years.
When the participants were shown pictures of food items after a four-hour fast, it was found that those in the successful weight loss maintenance group responded differently to these pictures compared to the other groups.
Specifically, researchers observed strong signals in the left superior frontal region and right middle temporal region of the brain – a pattern consistent with greater inhibitory control in response to food images and greater visual attention to food cues.
“It is possible that these brain responses may lead to preventive or corrective behaviors – particularly greater regulation of eating – that promote long-term weight control. However, future research is needed to determine whether these responses are inherent within an individual or if they can be changed,” said McCaffery.
The study has been published in the American Journal of Clinical Nutrition.